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Hey all I'm trying to figure out an issue I have with a motor that I built. It is a mid 70s CB750k. I completely tore the cases apart and had them blasted and I painted them. I'm going to lay out everything thats in the motor and what I have done so far. Pistons: 850cc 65.5mm bore from cyclexchange (no longer available) Cam: Cyclex CX-1 cam (http://www.cyclexchange.net/camshaftpage.htm) with new valve springs. Ignition: ARD magneto which was rebuilt and verified in good working order by mainley magnetos. Fuel: Weber DCOE 40s (which I rebuilt) mounted to a Russ Collins manifold. About two years ago after I got everything put together I was able to get the bike running. At that time I did not have a throttle cable so I set the idle to its highest point and kicked it until it started. It was difficult to get it to start but it did start and run and idle. I had some things happen in my family and I didn't mess with it to much and when I got back to it it wouldn't start at all. I pulled the carbs and went back through them and I sent the mag off to Mainley to have them rebuild it. I also changed the spark plug wires since they recommended solid copper core wires. Below is the troubleshooting that I have performed so far with that motor: Rebuilt carbs again. Magneto rebuilt and verified good working order. Verified ignition timing. The magneto does not have a advance so you must set it to fire when the motor is at full advance. It also does not fire a wasted spark like the stock ignition. So I verified the firing order which is as follow (1, 2, 4, 3). Verified cam timing was correct. Verified piston ring gap was correct. Verified valve lash was correct per the cam card. At this point I was extremely frustrated and I should note that all this occurred over the space of at least a month. I have another late k motor that I bought with a bike that was stock and complete. I pulled the magneto and carbs off my motor and put it on the late k motor and it basically instantly started. At this point I put that motor in the bike so I could ride it around and shake it down. It ran basically perfect once I got the carbs dialed in. So now I have done the following: Pulled the top end off the motor that was running and verified they were stock pistons and cam. Installed the stock bore onto the bottom end that I put together. (At this point I used my MLS head gasket that was for the big bore). I put the mag on the motor and attempted to start it with starter fluid and not carbs (These motors and in fact any motor will run for a few seconds like this) and could not get anything from it. Once again verified spark (with a spark checker like this one https://www.amazon.com/Ram-Pro-Engi...XEEK0NARJK4YXH7) After realizing that I had the wrong head gasket I ordered the correct one and installed it today but still the motor will not even attempt to fire. At this point I am putting the big bore jugs and the head that was on the big bore on the late k bottom end. But if that motor runs then I have zero idea why the other motor won't even at least try to fire. I realize this is a lot but I'm seriously at a loss as to why this motor won't run. As a foot note here I also brought the motor to a shop and they pulled it apart and could not get it to run either. Valt fucked around with this message at 00:11 on Sep 21, 2020 |
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Sep 20, 2020 23:43
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Well in case anyone is interested I finally determined what was going on. I had originally set #1 to be one plug on the cap. But the shop that had it the last time moved #1 to a different plug. The only way I was able to determine this was to pull the cap off the mag and move it to where the marks line up and saw it was on a different plug. After hooking it up correctly I was FINALLY able to get it to run. Here is a picture that shows the markings on the mag. 
Valt fucked around with this message at 00:44 on Sep 26, 2020 |
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Sep 26, 2020 00:41
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The bike is not in any way related to a stock 750 other then the engine really. It is not really a thing that CA cares about so I don't really ever bring it up. This is the most recent picture of have it together before I started changing parts on the motors. I had it together and with the stock bore motor it ran really good with the mag and the webers. It was not perfect and definitely needed some fiddling but it started easily and idled fine. Since the mag is full advance at all times at some point you have to realize its not going to idle perfect. 
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Sep 26, 2020 21:22
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Coydog posted:An I4 vintage custom chopper?! The frame was custom made by a friend of mine who does fabrication. Its based off a denvers chopper. The front end is like 40 inches from the axel to the bottom triple tree I think? I made the handle bars, brake, kick stand mount, and modified the shifter lever. The rear tire is a shovelhead rear tire and sprocket. The oil tank is a panhead oil tank that was modified to fit the frame. The kick stand was actually a huge pain in the rear end since the bike is slow low to the ground and the exhaust is so close to the frame. I ended up modifying a dyna kick stand mount and that actually worked perfectly. Valt fucked around with this message at 00:57 on Sep 27, 2020 |
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Sep 27, 2020 00:51
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It's not remotely my thing but I demand to know more.
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Coydog posted:What do you mean lots of people in here have KTM's. It’s only unpainted because I need to shake it down to make sure that nothing else needs to be modified. It will eventually be painted black with a little gold flake and gold leaf filigree on the tanks and certain parts of the frame. I mean honestly once you are moving a bit it rides like any other motorcycle. Slow speed turns take some getting used to and because it’s so long and low it scrapes if you are not careful with it. I will make a longer post detailing some the fabrication I have done. As well as the engine work I have done, as it’s a LOT.
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Sep 27, 2020 21:50
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Prior to this I had a CB750 that was hard tailed in a stock frame. I wanted to build something that was more then just a stock bike with a hard tail on it. I determined that I was going to use a 750 motor again since I was very familiar with them at that point and I had not seen any nicely done 750 choppers in person. The whole bike was built around the front end, wheels, and motor. My original plan was to have a Drouin supercharger and ARD magneto. But finding a supercharger proved to be basically impossible. So I determined that I would run the webers using a Russ Collins manifold. The reason I just didn't use points and stock carburetors is that if I was going to go through this whole effort of building the bike. I didn't just want to put a boring stock motor in the thing. Here is a picture of the frame after Matt Hurtado finished it, I will note this picture was taken in July of 2012: The motor was a several different motors put together. I took it completely apart and and had everything blasted. At this time I also bought a 850cc piston kit from Cyclexchange and had the jugs bored out for the pistons. I had a local guy polish all of the covers and the mag body, and I got it all put together (Jan 2016):  After this I slowly worked on getting parts and working with Matt to have him fabricate things on the bike. It was also during this time that I started to learn how to weld and do more fabrication then what I previously had done. At some point I decided that I would pick up the bike from Matt as I felt comfortable I could finish the fabrication that it needed. After getting it back I went ahead and put the real motor in the bike (before it just had a mock up motor that was just empty cases), I was able to get oil lines setup so the motor was plumbed and ready to run at this point (May 2018):  At this point the bike did not have a throttle cable as getting a cable that would work in my setup is no easy feat. First of all the throttle levers on the webers are mostly designed to be in a car and not pull up in the way they do in my setup. Second I was told that back in the day people used CB450 cables in these setups, which would be fine if this was in a stock frame. In any case I was able to set the idle as high as it would go and kicked it a million times and got it to run for the first time ever! https://www.youtube.com/watch?v=PvQcbUSCB5Q&t=73s Not to long after this I got a call from my step father telling me that my mother had lung cancer and that it had spread to her brain. I ended up going to florida where she lived shortly after that with my sisters to help him take care of her. After months of treatment and struggling she passed in october. After that both of my Grandmothers passed, so I honestly had no interest in trying to work on the bike for about a year. One of my best friends who originally helped me figure out what I wanted the bike to be ended up helping me get back to working on it. It was at this point that we got a lot of stuff done. Two of the things that I was concerned were going to be problematic were the brake setup and the kick stand. I had originally intended to use a sportster rear wheel but changed my mind since the sportster drum is fairly small and would quickly run out of braking due to overheating. So I ended up using a shovelhead rear wheel with a disc and PM brake caliper. Obviously this frame is completely custom made and has no premade brake mounting setups. The master cylinder mounting was fairly straight forward as I just made two tabs to bolt it too, and frankly these tabs are way overkill for the master cylinder:  The harder thing to figure out was the brake arm since it needs to pivot and drive the master cylinder. What I ended up doing was buying a shouldered bolt welding that to the tab so that the tab and the post did not move. Then I welded the brake arm (which I made by bending some round stock with the my oxy/acetylene torch then welding a stock honda brake pad to it) to the bushing and welding a tab to the bottom of the bush to drive the master cylinder. I then used a spring that sits in between the tab and the brake arm as my return spring. This actually ended up working perfectly!   The kick stand was a whole nightmare to deal with. The bike is very low and the exhaust sits VERY close to the side of the frame. This is a problem since most kick stands just pivot on a tab, so there was no way to mount a tab based kick stand and have it clear the exhaust or be able to actually pull up. What I learned after looking at the Dyna. Is that the kick stand comes out at almost a 90 degree angle from the mounting. We were able to get this mocked up and found that it actually worked perfectly! The only issue is that it will not pull up positively, it will stay up but the way a dyna kick stand works is the whole mount pivots on a pin so it can change its geometry when it moves. This is actually a more compact version of panhead style kick stands. But in the way that we mounted it, the mount cannot pivot, which is actually okay as I mentioned that it stays up once you put it up. You can see how close it is in the pictures below. I cannot stress how much of a victory this was for me and my friend. This represents probably a month of work and research and buying parts.   This is getting incredibly long at this point, I'm going to take a break but I have more about the cables and handlebars. Here is a video of my first time riding it, which note I'm not wearing a helmet since I wanted to make sure nothing was going to explode. I have a fully face that I wear when I am riding further then half a block. https://www.youtube.com/watch?v=9VdQs9nOjcM
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Sep 28, 2020 00:20
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So the next installment here is about making new handlebars. After I got the bike back I decided that I wanted to change the handlebars. The previous bars were made by Matt but I kind of wanted something different after being able to sit on it and move it around a bunch. I looked around at a bunch of other bikes with long front ends and decided on something that came back a bit. But I didn't want bars that were just bent over, I wanted some kind of shape. So I borrowed a tubing bender from my friend and drilled holes in my garage floor so I could mount it. The thing that makes getting these bars made so difficult is that they are two pieces and not just one piece like say the bars on the harley. They mount through holes in the top of the girder (the mounting is acutally the same size and width as anything harley as far as I know, the dyna uses the same layout). So that means if you are going to say have three bends like I do they ALL have to be exactly the same. If you think about it these bends are not all on a 2 dimensional plane so a TON of time was spent measure and marking the bars to try and figure out where to make the bends and how far to bend them. The whole process probably took the better part of a month and several sticks of tubing from the metal shop. But after a lot of trial and error my friend and I were able to get a shape that we liked and importantly we were able to duplicate it. I ordered some new bungs for the bars and tig welded them in. We also made a little cross bar so that the bars could not twist, which because of how they mount they almost definitely would have twisted no matter how tight you got them.  I had to get these bars done so I could order cables for the bike. As I previously mentioned people that ran these dual weber setups generally ran CB450 cables since they already had a split for two carbs. But in my setup that cable doesn't work since its not long enough. During this time I was able to find a place in Australia that sold universal throttle arms, these let you clock the arm into what ever location you needed it. In the below picture you can see how the cable goes to the throttle arm. I was able to find a pivoting cable clamp to hold the ends of the throttle cable and I believe it came from a go cart or lawn mower or something like that. Since the way this works is there is no end on the throttle cable I bought a solder pot and soldered the ends of the cables so they wouldn't fray.  Since the CB450 cables were to short, I contacted Motion Pro to see if I could get a longer cable. But that was going to end up costing roughly $150 so I decided to see if I could find another cable that would possibly work based on my measurements. After a bunch of searching online I was able to find a scooter cable that was roughly the length and size that I needed. I was able to cut the ends down so it was the correct size for me and finally I had a throttle that actually moved my throttle arms! I had previously reached out to Kiyo at Kyo's Garage as he has built several 750s using weber setups but he wasn't really able to answer my questions. This just leaves the clutch cable, which if I had just used a honda clutch lever it would have been fine. But there are several problems with this, first of all my bars are 1" and the 7/8" that honda bars use. Secondly the honda clutch levers are fairly ugly. What I wanted to use was a panhead style clutch lever. Which would mount fine on the 1" bars but obviously the cable mounting is very different. First of all Panhead clutch levers have no provision for adjustment, because on a panhead you have something called a "mousetrap" which was a piece that helped you get more leverage and make the clutch pull easier. I have circled in blue here:  For this cable I was going to HAVE to order a custom cable from Motion Pro. They requested that I send them the measurements, the original honda cable and lever, and the panhead clutch lever. They were able to make me a very nice cable that has adjustments in the middle of the cable. The nice thing is if I break this cable I can always just re-order it from them and it won't cost anywhere nearly as much. I think the cable ended up costing about $150 after shipping and everything else. Anyways I think thats just about enough for this time, next time I'm going to talk about the lights and their setup on the bike. As well as touch on inspirations for the frame and the race parts on the motor.
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Sep 29, 2020 20:17
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On a little bit different note I finally got around to modifying my engine stand so I can mount 750 motors. I'm seriously tired of wresting these things around on my bench its going to be so much nicer to just wheel it around and flip it over when I need. I had actually bought a engine stand from lowbrow thinking it could be mounted to a engine stand but that ended up not being the case. https://www.lowbrowcustoms.com/prod...fhoCHCMQAvD_BwE I have an engine stand that I have had small blocks on before so its a pretty beefy deal. I saw that cyclexchange had modified a normal engine stand to mount a 750 so I basically just copied that. You can see the cycle x stand in their engine videos. https://www.youtube.com/watch?v=NUgWuSqap6I All of his stands are a little bit different but the concept is the same, essentially cut the arms so that they can be welded to the plate and hold the rear two motor mounts. a fully assembled cb750 motor only weighs about 220 pounds and this steel is like almost 1/2" so its extremely overkill but it works well. I had to rig it up big time to lay out how I needed to cut the arms and where they needed to get welded onto the plate. But with the combination of magnets and milk crates I was able to get it tacked up then welded. I have never actually had my welder turned up that high so the welds are pretty gross but its definitely beefy enough to hold a 750 motor.   I currently just have a mock up motor mounted to it (no internals). But I am definitely going to be putting motors that I work on the thing. You can see the current state of things here, there is at least 3 750 motors or more in this picture. The one on the bench is actually on that lowbrow stand. Its actually nice since 750 motors are not flat on the bottom so if you just have it sitting on the bench it will rock around and are a pain in the rear end to move around.  I have another bike that I am going to finish once I am done with the long bike. I bought it as a complete bike (in pieces) its an old hard tail frame which as best we can tell was some kind of digger frame. Its actually quite the enigma since its obviously well made and was almost assuredly done in a jig but we can't find any markings on it and it doesn't match any other Honda chopper frames. It has a really cool feature which is that the entire rear motor plate is removable and its chromed. Again this isn't something that we have seen in any other Honda chopper frame. But eventually I will need to go through the motor thats in the bike, since its a complete unknown. It turns over and has compression but that is ALL that I know about it. In the pictures it has a stock honda front end on it which is way to short for it so it looks kind of weird. Plus all of the bars and tins are just what came with it and I would definitely change a lot of that stuff.   Its likely that the frame was intended to be setup like the bike in this video. https://www.youtube.com/watch?v=Q4BHitIzw2k **Edit** I know that I am just writing a bunch of stuff about like making the handlebars and no pictures. Honestly we were just trying to get it done and not document it. But I can make an effort to try and document the little fabrication stuff that I am doing in the future. Most of the time I'm just out there by myself trying to get stuff done and I forget to take pictures until I'm done. Valt fucked around with this message at 04:22 on Oct 2, 2020 |
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Oct 2, 2020 04:15
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So as an update to my original post I FINALLY got my 850 setup running. I'm still not exactly sure what was wrong originally but I think that the spark plugs not being fully seated in the mag cap was the main cause. I did notice that it probably won't start on the starter motor at least not right now while its super fresh. I used a spark checker tool and it was just barely lighting up. But I half heartedly kicked it and it tried to start. So I unplugged the spark checker tool and gave it one good kick and it IMMEDIATELY started. I am waiting on a valve cover gasket before I really try and let it run. But this is a HUGE relief, I have been working on this big bore setup for the better part of 6 months now. I will get a video of it running tomorrow and also do a little write up on the lighting on the bike.
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Oct 18, 2020 22:04
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GnarlyCharlie4u posted:Just out of curiosity. Have you ever used any of the offerings from Cycle Exchange? http://www.cyclexchange.net/ Yah lots of stuff in the motor came from ken. The 850 kit, all of the gaskets, and the cam. They make great stuff!
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Dec 3, 2020 04:53
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So I know I mentioned I was going to do an update on the lights and I promise I will get to that. But I wanted to do a quick post on the valve cover that I am modifying for the bike. A normal CB750 valve cover has a little drive for a tach, which I am obviously not using. They make a plug for this drive since it will leak oil if you just leave it open. But I have seen examples of the covers where they removed the drive entirely from the cover. So my friend cut out a patch from another cover and tacked it onto a cover with that section cut out. Seen here with a smoothed cover for comparison:  I practiced a bit with a tig welder on some other junk covers I had to try and get an idea of how it would weld. Since welding cast aluminum is much like trying to weld a marshmallow with a propane torch. I have some practice welding stainless and regular steel with the tig but almost none with cast aluminum. I brought the cover over to my friends house who has a big miller tig. I was able to get it mostly welded together but ran into an issue chasing pinholes.   I messed with a bit more, but I finally broke down and bought a eastwood tig 200 digital machine for my garage. I have had my mig for some time and it definitely works for a lot of what I do but honestly most of the welding I do is better with the tig. A lot of it is small welding or in tubing, which is just so much easier to do with the tig.  I am still trying to figure out the best setup for welding aluminum with this machine. I went ahead and ordered pure tungsten rods since they are apparently the best for welding aluminum. I attempted to do some welding with the grey tungsten that I have and it works but its maybe not the best? I am certainly not professional so I don't really know. It seemed like the arc was not stable and I had trouble getting the weld pool to start. here is some of the welds that I attempted with the new machine. I also preheated the valve cover at 200 degrees in the oven before attempting to weld and that did seem to help.   My tungsten should be here today so I'm going to try and finish welding then start grinding and blending the valve cover this weekend. I might get to posting about the lights today as well.
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Jan 22, 2021 18:03
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Sagebrush posted:I use the blue lanthanated rods for everything, AC or DC, and they're fine. They don't melt as fast as the green pure ones and they aren't radioactive like the red ones. Yah the pure tungsten is working alright and yah that’s exactly what I’m doing just building weld and trying to make sure the puddle looks clean before getting off it. I really need to get a tig finger for this type of work as well. Since aluminum gets ripping hot almost immediately.
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Jan 23, 2021 21:58
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So I spent about 3 hours today welding, grinding, and filing on the cover. Its getting much closer to being to the point of getting final sanding and polishing. I'm obviously still trying to learn all of the ins and outs of this welder. One thing I noticed is that once I got the tungsten to ball up it would not strike an arc again. I had to sharpen it every time. I also had to go up in my amperage, I think I have it set to nearly 90 amps now. But the cleaning is set to 45% out of a max of 50%.  
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Jan 24, 2021 03:56
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Update time! So I wanted to talk about the lights for this thing. Firstly this bike will 100% never see unlit roads at night unless its some kind of emergency and if so I'm going 5 mph. I don't even ride the dyna on unlit roads at night, to many deer / hogs around here to ever even think about it. So for the headlights they are the most custom part of the lighting. I wanted to have dual headlights since the front end is so large I thought that the bike would be strange with just one small headlight. The guy who built my frame made the headlight mount which is stainless steel, and its fairly thin. The headlights such as they are, are PMC 401 lights, these are old tractor backup lights. PMC is actually still around and they make lighting for trailers and tractors. These lights often get used on custom bikes since they are very small and have an interesting lens. The lens on these lights obviously is not meant to direct light and just scatters it which is fine since I want people to be able to see me. These lights originally used a 1157 bulb like what you would find in tailights for old cars (like my 67' C10 for instance). Even the LED version of these lights are really not any good for anything more then a hint of light. So I wanted to put and LED panel of some sort in the lights but wasn't sure exactly how to go about it. After some searching I found these 4x4 marker lights that shop right down the street from me had. They fit almost perfectly inside the housing, so all I had to do was remove the stand of the 1157 bulb. I also didn't really want to have to modify the housing to mount them, so I tried hot glue at first but that clearly did not work at all since its to hard and won't bond with the metal. My friend told me about clear construction adhesive that he had used for a similar purpose in the past. So I grabbed a tube of that and was able to get then set in place. This is actually ideal since they are easily removable in case they fail and nothing was changed about the housing.  The rear taillight was much more straight forward since again I needed something small but bright. Its actually just a custom piece that I bought from after hours choppers. It is very very bright for how small it is and he was super nice to deal with.      
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Feb 7, 2021 22:41
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So another exciting thing has been that cylinder #1 is basically throwing oil out of the exhaust. I'm not really sure why this happening though I suspect its something to do with the head / valves. I did a compression test on it since I think #1 is the cylinder with the rings that I had to source outside of what came with the pistons. But honestly at this point I don't even remember. But I did a compression test and it went up past 150psi so the rings are fine. The valve guide seals that I bought for the head thats on it never seem to fit right so thats what I suspect. I tried to do a leak down test but anytime I put pressure to it, the motor just rolled over. So it could be a seal somewhere on the head as well.
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Feb 8, 2021 00:34
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GnarlyCharlie4u posted:Motor turning over on leakdown is a good sign but it's still worth it to get a wrench on the flywheel and do a proper leakdown. Unfortunately there isn't really a way to put a wrench on a CB750 crank. As you can see the mag is replacing the points setup where you could maybe put a wrench on it. But now with the mage on there, there is definitely no way to do this. I'm not really worried about the head being toast since I have a good head thats replacing it. But it would be nice to confirm that is where the oil is coming from.
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Feb 8, 2021 04:48
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Valt posted:Unfortunately there isn't really a way to put a wrench on a CB750 crank. As you can see the mag is replacing the points setup where you could maybe put a wrench on it. But now with the mage on there, there is definitely no way to do this. I'm not really worried about the head being toast since I have a good head thats replacing it. But it would be nice to confirm that is where the oil is coming from. So I went ahead and took the valve cover off to see if a valve stem seal came off or something. Sure enough the exhaust valve, valve guide seal had come off. I double checked the parts fiche on bike bandit and the valve guide seals are the same for all years and k and f models. Maybe these are not great seals or something? But they never seemed like they fit properly. I'm going to pull the spring off and reseat that seal and hopefully get it up and running again.
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Feb 9, 2021 01:18
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mewse posted:Not sure if this will help or not but this is a youtuber I watch who does a lot of work with Honda engines and he posted a video dealing with valve seals a few months ago Oh I had already replaced the valve guide seals on this head. The valve guide seals seemed to not seat in the same way other ones I have dealt with. Since I have done this several times on several different motors. The video you linked is just a guy replacing old ones which can be problematic. After I reseated the valve guide seal the motor runs clean again so that is a relief!
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Feb 10, 2021 03:15
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Well I finally ordered the rest of the stainless tubing for my exhaust. I just need to get a set of purge plugs and a different regulator for my argon tank so I can use it to purge. But hopefully I can get started on that this weekend. I also ordered a tubing polisher for my angle grinder so I can better polish the exhaust and also all of the bare metal that is going to get chromed.
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Feb 23, 2021 15:55
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GnarlyCharlie4u posted:I spent way too long trying to figure out why you could possibly need an argon tank on your bike. Yup here it is! Almost all of the ones I have seen just come with them already attached to the angle grinder but this one is supposed to bolt onto a 4" grinder. Apparently this is metric and almost all angle grinders we get are imperial. But I saw lots of people just saying they just drill and tap it for imperial fasteners. https://www.amazon.com/gp/product/B086SZZCBC/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 Also here is the dual outlet regulator I bought for my Argon tank. This lets me either run two welders off one tank or purge and use the Tig welder with the same tank. Which is super useful for me since my Argon tank is huge and I likely won't have to refill it for a long time. https://www.amazon.com/SPARC-Regulator-0-60CFH-UNF-18RH-WARRANTY/dp/B07112PFVJ Valt fucked around with this message at 19:41 on Feb 23, 2021 |
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Feb 23, 2021 18:06
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Well I finally broke down and ordered the tubing that I need to finish my exhuast. Here is what $200 of stainless tubing looks like! My plan is to have all the tubes kick up at about a 40 degree angle and then give them a slash cut. I used some tig wire to get an approximation of what I am going to do.  I also gave the exhaust a quick polish. Eventually I want to try and blend all the welds and get it to look like one smooth tube. I think I will have to end up adding weld to some areas to accomplish this. But some areas might require some real fiddling shaping.  The exhaust colors up nicely and I think this will look really cool against the black and gold flake paint its eventually going to get. 
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Mar 1, 2021 20:25
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Toe Rag posted:That looks great. Is it extremely loud? I suppose on most motorcycles the exhaust isn’t in front of you. I guess that would depend on your definition of loud. But I would say it’s on par with my dyna which just has aftermarket exhaust on it.
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Mar 2, 2021 06:11
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So I have been practicing stainless welding on some scrap tube of the same type I’m using. Found that I prefer a #8 cup with a gas lens and using pulse. The pulse helps keep me from overheating the stainless. The Miller welding settings calculator for getting a good baseline on materials I am not familiar with. https://www.millerwelds.com/resources/weld-setting-calculators/tig-welding-calculator You tell it the thickness and type of material as well as what type of weld it will be. Then it gives you some basic settings to start with and sizes for tungsten and filler rod. *edit* I also replaced all the valve guide seals since I had one that kept coming off the valve guide?!?!!? I have never seen that before but the ones I put on I have experience with on other motors. I also put in the new springs since I just had them on the other head while I wait for the head with stainless valves to come back. Thankfully I ordered that leak down tester, I was able to pressurize the cylinders and do all the work without taking the head off. Valt fucked around with this message at 20:17 on Mar 7, 2021 |
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Mar 7, 2021 20:11
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I have been practicing welding on stainless tubing. I'm getting better and using the pulse setting has helped me a lot. Since it stops me from sitting in one spot and overheating the tubing. I also back purged this test piece and that made it better as well. Once I had the tubing welded I polished it with my tubing polisher and I'm pretty pleased how it turned out. Mind that this is just a test piece for me to practice my tig welding.   I also got started on changing my seat. Originally we had put down some stand offs on the frame as I was concerned I would sit to low on the bike. This turns out to be a non issue. So I can the stands off and I also shortened the seat pan, since I want to have a more vertical sissybar. I also put on my taller sissy bar that I made and I think I am liking the taller bar more. I just need to make the mounts for the seat and then its going back to the guy who originally made it. So that he can put the foam and cover on it. We had originally used black velvet on the top, but it faded really badly in the sun. So now the top is going to have newbuck leather and the sides will just be black leather.  
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Mar 15, 2021 17:11
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Well I finished modifying my seat pan today. Its currently just tacked in place so I can verify everything before fully welding it. So instead of the seat bolting to the sissy bar there is now a bung on the top of the fender and a tab on the back of the seat pan. I also had to change the front mount on the seat pan but I'm not happy with it yet. I mounts basically like a harley davidson seat does, with the bolt in the back on just a tab that slides into a mount in the front. It should be noted that most of this won't be seen after the seat is covered.  
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Mar 21, 2021 04:41
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Valt posted:Well I finished modifying my seat pan today. Its currently just tacked in place so I can verify everything before fully welding it. So instead of the seat bolting to the sissy bar there is now a bung on the top of the fender and a tab on the back of the seat pan. I also had to change the front mount on the seat pan but I'm not happy with it yet. I mounts basically like a harley davidson seat does, with the bolt in the back on just a tab that slides into a mount in the front. I completely spaced getting pictures of the finished welds. But the welds on the back tab are nice since it was all new and clean. I honestly should have just mig welded the front tab since it was spliced into what was there before. None of this stuff is load bearing and honestly is a copy of what harley does with their seats. I'm hopefully going to get the seat back before the 11th of next month. There is a swap meet happening in fredericksburg next month that I want to ride too. https://thetexasfandango.com/ Valt fucked around with this message at 02:40 on Mar 22, 2021 |
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Mar 22, 2021 02:00
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So I tacked the lower mounts in the taller sissy bar. I also got my bungs to for the top mounts on the fender. I'm going to have to take the fender off to weld the bungs on so there is going to have to be some layout before that happens. Once thats all done I will cut the back of the fender off so its closer to the sissy bar like it was before.  I'm not sure I'm sold on the vertical plate mount. But I think in either case I'm going to have two bars that hold the light in the center of the sissy bar. So from the back it appears to be floating in space. Thats actually going to be somewhat difficult because it will need to be centered in 3d space. Its getting the same tail light thats on the other sissy bar as well. I'm also going over to a friends house this weekend with the bike so we can work on the seats foam shape. 
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Mar 26, 2021 15:54
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moxieman posted:This is my favorite thread. Please keep posting, you’re doing very cool work! Yeah my progress has been pretty slow. But I'm starting to pick up the pace a bit now since I have everything I need. I need to take the fender off so I can get the bungs welded on but that isn't a easy task since the wheel has to come off. I'm also going to change the mounting of the oil tank so that it sits flush to the underside of the frame. But again thats kind of a undertaking since I have to drain the tank and fiddle with a bunch of stuff. But over all it will be a much cleaner look with the tank flush to the underside of the frame.
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Mar 26, 2021 18:14
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helno posted:Never been much of a chopper guy but wide engines on skinny frames look so much better to me than the typical v-twins. Yeah I saw the pictures of the blue 750 in the other thread. I think you would be surprised at how totally different of a bike it is with accelerator pumps on the carbs.
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Mar 27, 2021 01:21
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Well I got a lot done today. I finally got around to getting my mounting tabs for the fender welded onto my sissy bar. I also modified a tail light mount to mount my after hours choppers light, this is the mount that I got https://www.lowbrowcustoms.com/prod...NRoCyXoQAvD_BwE. This is how I modified it so basically the light sits just above the license plate.  I also temporarily mounted a solo seat since my other seat isn't going to be finished by next weekend. A bunch of us are going to ride out to Fredricksberg for the Fandango, which is a big swap meet and some vintage racing stuff. I will get pictures of the mount but its extremely basic since its just 1/4" flat bar and I put some hose over the bolts in the back of the seat so it doesn't mess up the frame. https://thetexasfandango.com/  Here you can see everything tacked in place. I actually goofed and the light mount is a bit cockeyed, but it just has a couple of tacks in it. Everything else is now fully welded as I verified it is where it needs to be. Now I need to take the fender off so I can weld the bungs into the underside of the fender. Plus I need to run some double sided tape under the fender so the wiring can be hidden. This is essentially how Dyna's and probably a lot of cruiser type bikes run the brake light and turn signals.   In non motorcycle news, the 49' in the background spun a rod bearing. So I bought another motor for $150, but its seized though I think I can pull a rod out of it and replace the one with the spun bearing in my motor. I also found that one of the tie rods was extremely bent, so thats getting replaced. Hopefully I can get it going within the month, it also needs a gas tank since the old one literally rusted a hole in it.  
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Apr 5, 2021 03:00
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Well I attempted to ride out to the Texas Fandango today on the Honda. I ran out of gas pretty early on which was annoying. Since because the way the tank mounts there is basically 0 reserve. But worse then that first gear appears to be hurt. Sometimes when I get into first I get a awful gear grinding sound. It had only happened a couple of times in the past month but it happened a bunch today. I ended just parking it and calling triple a since I didn’t want to hurt the motor. So tomorrow I’m going to pull the motor and split the cases. I obviously have other transmissions. But my concern is that the power level and violence of it with the hard tail and different carbs is just going to break the trans again. Valt fucked around with this message at 01:52 on Apr 11, 2021 |
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Apr 11, 2021 01:48
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GnarlyCharlie4u posted:Yikes I didn't realize that would be so much of a concern. Yah I’m not really sure it’s just my hunch. But I will see if there is carnage in there today. I have certainly heard that the shift forks can bend. But that normally causes issues in all the gears. I also need to actually figure out why it’s blowing oil. I suspect it’s worn valve guides but it has new valve guide seals so I’m not sure if that would still cause that. The rings are new and it has good compression so it’s not that for sure.
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Apr 11, 2021 14:11
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Oh there was carnage.
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Apr 11, 2021 20:14
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Slavvy posted:Those ring segment looking bits are pretty alarming, they look like bearing retainers or something...? Oh sadly no, it just got way more expensive. Thankfully I have another bottom end, but the main issue here is I can't get these pistons. So I have to get a totally different set of pistons then have another set of jugs machined for them.  
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Apr 12, 2021 02:59
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GnarlyCharlie4u posted:gently caress. I actually have several sets of jugs. What I'm probably going to do is use the 78 motor it just needs to be painted and get a clutch. But now I'm going to have to get new pistons and get those jugs machined. Thankfully pulling the motor out of the bike is trivial really.   
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Apr 12, 2021 14:03
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Alright well I just ordered a set of weisco 836 pistons. So now I need to get the other motor up on the stand and get it ready to be painted. I also need to pull the covers off the dead motor and give them another round of polishing. Before I put it all back together I think I'm going to get a barnett clutch for it too since I'm pretty sure that motor has a roasted clutch. I'm also looking at a much bigger cam then what I had originally put in it (363a). Plus I still have the other head with stainless valves in it. https://www.dynoman.net/engine/cams/webcams_honda.html Valt fucked around with this message at 16:08 on Apr 14, 2021 |
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Apr 14, 2021 14:01
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Well I ordered Weisco pistons but apparently cycle x was out of those but they had the 836 JE pistons in stock which are essentially the same thing. In that they are both forged pistons and 836, however the JE pistons are a 1/4 point of compression higher. They arrived today, so hopefully I can get everything dropped off at the machine shop on monday. I'm going to put the motor on my engine stand that I made so I can get it ready to be painted. Plus I'm taking the jugs over to a friends so I can blast them and get all the old gross paint off them. Here is a picture of the new pistons in comparison to a stock piston and the 850 pistons that were in the bike. The stock piston is on the left, JE piston in the middle, and the 850 piston on the right. 
Valt fucked around with this message at 01:49 on Apr 17, 2021 |
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Apr 17, 2021 01:39
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So I put the other motor on the engine stand today to start getting it ready for paint. I took the oil pan off just to make sure nothing horrible was happening and found a pile of RTV. Because whoever messed with this motor last used a gently caress ton of RTV on the side covers for no reason at all.   Thankfully everything appears to be okay. No wonder it was leaking oil, the trans cover was basically just finger tight. But all of the threads appear to be okay thankfully. I started trying to get the liners out of the stock bore jugs and put them into my other jugs since they are already blasted and clean. In doing so I noticed something odd. The big bore jugs are bored off center, literally .5mm. I don't know if that would have caused my failure but that CANNOT be correct at all. 
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Apr 18, 2021 04:51
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Horse Clocks posted:For the unlearned, what are we looking at here? The bores are off center. I still don’t know if this would actually cause a problem. But at the very least it shows that the guy that bored them didn’t know how to set them up. There is 0 reason you bore off center like that. Literally one side of the jugs is half a millimeter thinner. Which in the realm of engines is gargantuan.
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Apr 18, 2021 19:48
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| # ¿ May 15, 2024 09:30 |
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Rev. Dr. Moses P. Lester posted:Will that really mess up things that much? I know that the spacing of crank axis and cylinder axis are finely optimized slightly apart, but I gotta say I've put together a lot of motors modified in numerous different ways and I've never seen a problem obviously attributable to that of all things. Looks to me like one of the many measurements in an engine, like piston dome shape, which you could get fairly wrong and it wouldn't affect anything other than peak horsepower by a few percent. It's not like the wrist pin and cylinder aren't going to get lubricated or anything. Nothing's going to bind on anything else. But I dunno I've never bored a cylinder myself. Yah I’m unsure as well but it just seems wrong at the very least. I’m actually headed to the machine shop right now so I will see what they say. So just got back from the machine shop. He brought up something I didn't even think about, the bores might not be straight in the vertical sense. In any case he agreed that having the bores be that much off center is not good and wouldn't have helped anything. But if they weren't straight that would cause more problems. Valt fucked around with this message at 15:21 on Apr 19, 2021 |
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Apr 19, 2021 14:38
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