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We're building a 50cc vintage race bike over here. Hoping to have it competing for 2016 but also hoping to have it rideable before this winter. Some backstory: Our shop already races a 1972 Honda CB350 in a classic bike roadracing club. Won the championship on it last year. And a 1972 BMW R75 sidecar and a 1958 Triumph Cub 200 and intermittently a 1987 Honda NT650. One of the other guys at the shop, a moped guy, recently got a top tank moped for free, and he was like, "hey man you and I should build something out of this" and I was like, "how about a race bike" and he was like, "yeah awesome." And we bought a 1965 Puch/Sears 4 speed 50 engine off a friend and took it all apart and then discovered it's loving impossible to get parts for and the crank is hosed and then we gave up. But at this point we were kind of committed to the idea of building a race bike. Then one of us remembered we knew a guy with a weird old Yamaha 50 street bike. Bought it off him. Forgot to take a "before" photo. It's one of these:  1982 Yamaha RX50. One of the ugliest bikes ever made. But it's a Yamaha with a 5 speed tranny and a clutch and a disc brake. That pretty much checks all the boxes. It'll be racing in fairly open class, basically it just has to be 50cc and it has to look like what pro 50cc bikes looked like back before 1984 or whenever they vanished. Apparently they never really made this bike to sell, they just produced a few thousand to use as promotional things for dealers to raffle off. Seems kind of pointless to me. Is someone gonna buy an XJ1100 because they got a free ugly tiny piece of poo poo? Got it running. That was a story in itself. Whoever owned the bike previously (not our friend) was some kind of weirdo. They replaced the air filter with a dryer sheet and filled the oil tank with something that didn't quite seem like oil and smelled like lavender. I tried to wash my hands with it, thinking it might be soap if it was perhaps owned by a resourceful but ignorant cleaning lady, but no it's not soap. It fouled the plugs constantly and caused all kinds of problems so one of the first things we did was disconnect the oil injector and run premix. Then we discovered the CDI was misbehaving. When it cranked up the advance above like 3000rpm, it would run something like 100 degrees BTDC instead of the 20 it was supposed to have. Replaced the CDI, it ran great. Thing is a loving blast to ride. Got it on the dyno for a baseline run, it managed around 4hp. We had a pod filter on it and didn't jet it properly for that so it's running lean and probably down on power a little. But hey, top speed 53mph (without wind resistance). Started yanking it all apart, spokes, forks, brakes, tank, seat, bars. We're trying to keep costs down so we're running a lot of parts we already had. 17" moped rims, moped pipe, clubmans, relatively cheap tires (not the $140 dealer cost vintage race Avons). Gonna try to fit the seat from the moped we originally had cause it was a good looking seat. Another guy at the shop bartered expertly with a guy who does fiberglass/carbon fabricating for bikes, so we're basically getting anything we want for it. Probably gonna get a fiberglass tank and a full fairing for it. That's gonna be totally awesome, thought we'd have to save up a couple years to afford that stuff. So here's where it's at right now:  Had to order some custom spokes which we weren't expecting. But all the spokes we had were the wrong size and it looked like a bad idea to lace it up with stuff that didn't fit. The original rims were 16 rear and like 19 front. Weird sizes. It's got a weird design where one of the front forks has a spring and one doesn't. I never liked asymmetric forks like that. Seems like a bad idea. It's got something weird on the swingarm pivots too. Instead of bearings or bronze bushings, it's got rubber bushings in there like the kind you'd put on either end of a shock. When I took the shocks off, the swingarm didn't really wanna move, it sprung back to its neutral position. Because those rubber bushings don't rotate. This is on the swingarm pivot, not the shocks. Another thing I don't get but am not sure how to fix or if I need to fix. Here's more or less what it'll look like when done:  This guy is using the same motor but he has a different custom frame and wheels. Our wheels will be spoke. Can't decide on the paint job. I was originally thinking a Kenny Roberts old style Yamaha design but with red/white/gray instead of yellow/white/black. But now I'm thinking just do the entire thing Ferrari red. Will post more as the work proceeds. Will update this general info chart as work proceeds too: code:Rev. Dr. Moses P. Lester fucked around with this message at 03:19 on Sep 27, 2015 |
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Jun 22, 2015 04:27
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Minkee posted:Now the real question is who is going to be the rider? astrollinthepork posted:Oh man I didn't know I wanted to do this until I saw this. What do you think the rough cost of this project is going to be? What kind of speeds are we talking about once everything is set up? As for top speed, we only have vague ideas. Our 350 maxes out at 80 something on that track (NHMS) so I'm thinking maybe 60 something for the 50? It managed a peak of 53 with stock gearing on the dyno so we got a slightly smaller rear sprocket. DefaultPeanut posted:Expected to see a YSR in the first picture, only half disappointed. If you are interested, I may have a spare std bore cylinder you guys could port the hell out of.
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Jun 22, 2015 14:34
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ought ten posted:THose welds look terrible Called Racetech today, turns out they don't make any gold valves small enough to use in these (27mm) forks. Guess we'll just have to rebuild them with some heavy oil (on the assumption that all 80s Japanese suspensions were too soft) and hope it feels ok. Trying to find out if there's a DuPont paint code for Ferrari red. Probably just gonna paint the whole thing red. Frame, fairing, tank. Might try to make a red vinyl seat cover. Might not, that's kind of a lot of work.
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Jun 24, 2015 01:56
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Our baseline dyno run from before we tore it all apart. Had a pod filter on it instead of the original intake, so it's running a bit too lean. Ignore the big spike at 4500, that was an rpm sensor glitch. Fully full on 4hp there bro.
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Jun 25, 2015 04:03
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I think the mix we had in there was 45/50:1. Either way we're gonna dyno it once it's all together to make sure it's right on with whatever mix we're using.
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Jun 25, 2015 19:21
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Did some parts cleaning today. Scrubbing the engine using degreaser. And a creemee.  Decided to remove the gray paint from most of the aluminum parts with a wire wheel to shine it up. Most of the engine covers, wheel hubs. Looks rad.  24mm flat slide Mikuni and carbon fiber reeds. The original Yamaha intake boot was so well designed we were able to just carve it out with a dremel a bit and it all fits great. 
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Jun 27, 2015 03:16
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We got some Hutchinson softish moped tires, 2.75x17. The real tires to get are either Avon non-DOT 18"ers or a similar Heidenau or a Battlax that's only sold through honda for the Dream 50. But all those are like 5x as expensive as the moped tires we got.
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Jun 27, 2015 21:49
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Painted the frame today. Sort of. I wanted a nice Rosso Corsa but the place we usually get paints from couldn't figure out the Glasurit->DuPont for that. Wanted to brush it on because it's such small tubing that a spray would be 90% wasted into the air. Didn't brush on real well, though. Too thin or something. Oh well, it's red. Red is all that matters in racing.
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Jun 28, 2015 01:28
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We actually had a can of Rustoleum red and I elected not to use it in favor of some expensive DuPont poo poo. Kinda second guessing that choice now. And I drilled some holes in a thing. 
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Jul 1, 2015 03:41
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I didn't think it through much myself, all I know is we did the same thing on another vintage bike disc and it's been fine through a season of racing. I "countersunk" the holes by hand with a small file, in the interests of not chewing up the pads too quickly. Also the bike is so light and slow that I'm assuming there's not really gonna be much stress on that disc.
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Jul 2, 2015 03:46
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Ordered some rearsets. Polished up and rebuilt the forks. Had to guess on how much oil to put in there because you can't get manuals for these things. And laced up the front wheel with a 17" moped rim and custom spokes but haven't trued it yet. It's like 0.080" out axially right now so I was annoyed and stopped there for the day. Wheel bearings are so small they won't fit our normal truing stand axle. 
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Jul 4, 2015 04:12
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Got the front wheel trued to 0.010" axial and i think 0.025" radial although it's a little hard to tell because I couldn't mount it on the truing stand properly because the drat wheel bearings are so small our truing axle won't fit. Did the last bit of chassis painting.  Did a lot more lockwire drilling. That's mostly done now thank god. Updated the OP with a race bike build chart, work to do, parts to get, costs, projected schedule, unknowns. Talked it over with the other guys and decided the rubber shock bushings used as pivots for the swingarm is not acceptable for racing. Gotta punch those out and engineer a proper bronze bushing replacement for them. That could be tough. Rev. Dr. Moses P. Lester fucked around with this message at 04:19 on Jul 6, 2015 |
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Jul 6, 2015 04:13
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Replaced a bunch of the goddamn JIS phillips screws in the engine with allens, installed some of the front end. Sadly it looks to me like those forks are gonna be way too tall, even with the smaller rear wheel. Might have to have them shortened. Disappointing, because if it weren't for that, I think we'd have spent our last major dollar on this bike already and it would be just labor from here. Punched out the stupid rubber bushings from the swingarm, took a lot more work than I would have thought. Gotta find some bronze poo poo and have them machined to fit now.
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Jul 9, 2015 02:42
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Problem is the top triples are not clamp-type triples, they're moped style where the fork cap bolt holds the fork and triple together. The fork can't slide through them. Top triple is just a stamped piece of flat steel. I'd like to keep the front end because it already has a good caliper and disc and etc. on it, and i dunno what other options there are besides customizing the forks or customizing the top triple maybe.
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Jul 9, 2015 19:30
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Made the rear wheel bigger and the front wheel smaller, but I'm pretty sure that front end is just too high. We came up with a solution, we're thinking about buying another steering stem for that bike (like $20 on ebay) and cutting the pinch clamps off it and welding them onto our upper triples. Then simply adjust fork height as normal. Got the rear wheel all together with tire on it now, removed all the wiring we don't want. Gotta take the swingarm to a machinist and see about having some bushings made and get a bunch of m6 allens from Fastenal next.
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Jul 10, 2015 02:45
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Every Japanese maker did that in the early 80s. Every single bike was a cruiser. It was a horrible time to be alive. As for the pipe, we were intending to do a minimal welding job to fit a standard 50cc moped tuned pipe on it. The pipe we had, though, turns out to be totally the wrong shape, and it looks like it'll get a lot more complicated than that. Not sure what we'll have to do. Waiting on the machinist to do the custom swingarm bushings at the moment. Once the bike is mostly together, with both wheels and rearsets installed, then we'll need to see how we can fit an exhaust on it. I've heard you can buy kits to weld together your own cones and whatnot for 2t exhausts, we may have to do that I suppose.
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Jul 18, 2015 20:37
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My reading on the topic suggests you need to be very precise with the taper angle and length of the cones on your pipe though. It's not just "big here little there ok throw it on the bike." I wonder how hard that is to get right with that technique.
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Jul 21, 2015 18:01
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Would the tapers be the same though? If I welded a certain angle and then blew it up, the angle in the resulting cone would be the same? That seems like the important part. I don't know enough of "the physics" to know how that works. We're thinking about buying an aftermarket moped expansion chamber and welding it to what's left of the original exhaust pipe. Anyway I was on vacation for a bit and we had to wait a while for a machinist to make some custom swingarm bushings so not much happened for a while. But we got the swingarm in, top triple trees modified, forks slid up, wheels on, shocks on. Decided to go with 1" taller shocks from a moped. Was a pain in the rear end to make the shock bushing eyelets fit the unusually large Yamaha shock posts.  We have a custom made fairing lying around waiting to be mounted on a 1958 Triumph Cub 200 race bike, so we threw it on the 50 to see how it would look. I think the fairing was originally designed to fit a Bultaco of some kind.   It doesn't quite fit but it's close. The steering neck is a bit far forward on the bike and of course the bars aren't really in the right spot. We may need to get some clipons, but hope not. Gonna talk to the guy who custom makes these fairings and see if he can mod the front end of it a bit. Make it taller to fir the bars and a bit of a cutout more forward to make space for the forks. And I'd like a more rounded torpedo shaped nose rather than the sort of smushed style this one has.
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Aug 14, 2015 05:45
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Attached some spools to the swingarm today. Made a rear stand for it out of a scrap scooter centerstand and scrap chrome barstool legs. Still needs a little modding. Needs a brace bar on the bottom to keep it from rolling over backwards when taking the bike off it, and needs some cutting on the left side because it's blocking the rear axle in, and needs a lot of filing and grinding to round off sharp edges. Could probably shorten that handle a lot too. 
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Aug 18, 2015 01:37
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Got the rearsets mostly on, duct taped an expansion chamber on and spent a couple days on the dyno. It didn't go that well. We think our carb is too big (24mm). Stock was like 16, and after loving with everything that can be hosed with in the carb, there's still all kinds of things going wrong with the mixture in the low/mid range. And the peak WHP is no higher than it was when stock (4.3). Also thinking our test pipe may not be good but unsure of how it ought to be different and it's quite a project to try another one. Basically involves finding another moped pipe of some kind, chopping it all up so it kind of mates with the stub header from the original pipe, and then dyno tuning to see what happens. Anyway, here's a video of it not running the way I want. https://www.youtube.com/watch?v=XwYh1rwMCEQ
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Sep 1, 2015 04:04
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I picked it because I saw another guy at the track with the same engine and he had that same carb on it. Also it's a flatslide and it looks awesome. But today I went back to the original (~17mm) on it and peak hp was exactly the same and the low end was much better. Only problem is that carb is almost impossible to tune, it has jets I've never seen before and can't find in any of our catalogs. I wanna try a more aggressive pipe but thinking we may need to buy a proper performance carb in the 18mm range too.
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Sep 2, 2015 03:43
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I just mean I need something that was made recently and uses standard performance jets and needles. The jets in the Mikuni TM24 flatslide we had on it were literally the same as the ones we have in our 38mm round slide Mikunis on our sidecar rig.
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Sep 2, 2015 19:32
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Yeah we were looking at both VMs and PHBGs. Did I hear that the Dellortos have a 3 jet system? I like the sound of that. Unless maybe there are a wider range of needles available for the VMs. The TM24 we had could only get one needle jet and only 2 needles.
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Sep 3, 2015 19:11
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Had a drag race today against a Buddy 50 scooter with a Prima pipe. (it's a p. fast scooter if you're not aware, bro) I won. So I'm feeling optimistic. Bought a copy of this thing http://www.buildandclick.com/html/tuned_pipe.html and ran the numbers on it. It came up with a pipe that seems surprisingly not that aggressive. Meaning the width of the expansion chamber at its widest is not nearly as wide as the Prima pipe on the above mentioned scooter. I thought that was kinda funny. From the reading I've done, it sounded like for peak HP you'd want a diffuser cone with a wide outlet and a baffle cone with a sharp taper. Maybe it depends on port timings which I assume are rather conservative on this bike. But I'm thinking about trying the hydroforming technique on the software's prescribed pipe this winter.
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Sep 5, 2015 03:43
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Good lord I had no idea such awful things were out there. I don't know for sure about the Prima pipe but it does have a repackable muffler at the end of it and it has PRO LEVEL looking welds all over the cones on it so it might be legit. So this last Monday we had the rx50 out for the first time on the track. I don't think I got any good pictures of it at all, sadly. Here's a bad one:  Sadly it looks like poo poo right now because: 1) still no fairing 2) still using the original hideous tank 3) the seat we had needs a lot more modding than expected, and the subframe too 4) same with belly pan and exhaust too maybe because we can't fit the belly pan under it yet Good news was it was doing ok on the track, passed tech inspection, didn't blow up, was kinda keeping up with other bikes in its class. Bad news was it turns out the rear brake was adjusted such that it was dragging in just the tiniest possible way and after 2-3 laps it would heat all the poo poo up back there and start to drag quite a bit more. Every little bit hurts on an engine that size, so it was noticeably down on speed. I never even used the rear brake except on the dyno, so I didn't think to check it for problems. Gonna regear it for the last race of the season which is on a faster track, and then think about mods over the winter. Clipons, custom exhaust, porting, port/case matching, maybe messing with the head to raise compression, a better (but not too big) carb, maybe a swingarm brace, and of course the bodywork. I'm also wondering if it would be worth the expense and effort to get ceramic or ceramic hybrid bearings for the engine and wheels, since noticing how every little bit of friction matters after the rear brake incident. And maybe just some light oil in the wheel bearings instead of grease, since I believe they'll have external seals over them anyway.
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Sep 12, 2015 02:58
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So we regeared it for NJ, up 1 tooth in the front. Turned out not to be enough. On a clear lap, I was able to go WOT in top gear for the entire lap. But the rear brake was fixed and it ran reliably enough that I could compete for not-last place. The guy I was fighting with had a honda Z50 engine, a horizontal 4 stroke of some kind. I was able to hit the turns harder than him, he was braking in some places whereas I never touched the brakes, but I wasn't doing good starts and his motor had me on the main straight. He used all the track, too, so combined with my lack of skill, it was tough to get by him. And you can't do any aggressive late-braking maneuvers when you're never touching the brake anyway. In one of the races, I wasn't able to get past him until like the last lap. And so I wasn't able to build up enough of a lead on the remaining turns to hold position on the straight. But on the other race, I got past him about halfway through the race, so I was able to build up a lead and hold it until the end. So that was p. rad. I'm cheap, so here are some ripoff photos from the serious photographer who was at the track: Behind the 670/14 group, all 3 of us were real close most of the race. 14 Isn't in my class, though. Here's me behind them in turns 2-3 I think.  And here's me having passed them a while earlier and just barely staying ahead at the end of the straight going into turn 1.  So I went home with a 2nd and a 3rd. I gotta hand it to Yamaha, I ran that thing in 2 races and 2 practices, WOT under full load for almost the entire time, and it never skipped a beat. So now it's winter rebuild time. Gotta decide what to spend money on. I'd like some alloy rims and sprockets and clipons and a different tach. Probably we'll have to keep it down to the stuff we don't have to buy. So gonna pull the motor apart, widen all the ports a little, see about loving with the head to increase compression ratio, and try hydroforming an exhaust.
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Sep 27, 2015 03:16
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The gearing was only an issue at that one track which won't be seen until September next year. The guy I want to be competing with (because he has the same motor as me) up front has a nice fairing and some motor mods. Although not many motor mods. Also has a totally different frame and wheels, so I'm wondering who has the advantage there. I picked some relatively wide (2.75") 17" tires for this bike but most people in the old 50s have 18" narrower ones, some of them 2.0 even. So far I think I'm seeing why they don't take anything wider, which is I've never gotten it that far over, so a fairly wide margin of the edge of the tire isn't getting used. But maybe that's just because I'm not going fast enough and leaning it hard enough. Especially at NJ it's absolutely amazing how sensitive the steering is on that bike, I have to be incredibly light on the bars to keep it smooth. The steering angle we gave it doesn't look that crazy to me but maybe it's wrong, or maybe it needs a damper, or maybe bigger wheels, or maybe a longer wheelbase. On the other hand if I just touch it real real gentle like it does seem to work, so maybe I should just learn to work with it. Oh and here's my greatest trophy yet  And at this last event there were a lot of other things to see, a vintage car race club, and some guy with a bunch of 80s Ducati race bikes on display, but who cares about those, this is the thing I wanna see:   An actual original 80s (maybe?) Kreidler 50cc GP bike. It is just the weirdest looking thing in person. It's like a foot high and the bars are like 10" tip to tip and ridiculously long. The ergonomics on it look like the worst I've ever seen on a bike. But it has a trellis frame and it revs to 17,000. Wow.
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Sep 27, 2015 13:39
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Ordered a gasket kit, clipons (they're amazingly cheap for 27mm forks), new tach. Pulled the motor today for the rebuild and mods. Noticed something. https://www.youtube.com/watch?v=LrtoBUjb6TE It had always been kinda rattly. I figured that's just how jap crap sounds, brah! Turns out it's got a crank bearing on the way out. I rode it around NJMP at WOT for about 45 minutes total, over redline half the time, like that. Pretty sure it was already like that because it always made that noise. Amazing.
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Nov 4, 2015 03:13
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Yeah that's the standard way motogp teams do it. But that's a psychotic amount of work. We might be able to just cut 2 things out of 20 gauge steel and weld the seams and pump it full of water.
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Nov 5, 2015 02:59
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Pulled the motor apart today. Amazingly there is no case gasket in this thing. The manufacturing is so good that they just used a little RTV and that's all it takes to keep the bottom end and gearbox perfectly sealed.  Magneto side of the crank didn't look that great, and I think I found the reason for that side's bearing being hosed.  The hosed bearing.  Little baby transmission.  Clutch big enough for a 125 motorcycle except that it only has 2 friction plates in it.  Top end with more fins than a motherfuck. Japs love keeping things cool.  One of many things I intend to lighten or remove. This is an idler gear that went between the clutch and the kicker and the speedo drive gear. Gonna remove the kicker entirely so I'm thinking about drilling a lot of holes in this heavy steel gear.  Piston looked amazingly good considering what I had recently been doing to it. 
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Nov 7, 2015 03:50
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Yeah this thing is old and low tech enough to have an all iron cylinder. But I guess Japanese machining is Japanese machining.
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Nov 7, 2015 15:05
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Been doing random things but still a ways away from putting it all back together. Took apart the shocks, painted them something other than black.  In retrospect I wish I had painted the springs red.  Spent a lot of time wire brushing the paint off anything that was black.   And some things that weren't black.   Installed plugs in that cover to block off the seal holes where the kickstart shaft and oil pump shaft used to be. Got the motor all back together, well temporarily anyway. The top end is still undergoing some work.  Had some material welded into the head to up the compression ratio, shaped it into a sensible combustion chamber, then used some bondo to mold the inside of it and measure the squish band. Was like 3 times what it should be. So now the cylinder is at a machinist to be cut down a little to get the squish band right. Will have some pics of that before too long. For the previous few months I had intended to slightly modify the CDI to make the advance adjustable. I dunno if I mentioned that before. I used acetone to open up the original CDI and intended to replicate it with a potentiometer in place of one of the resistors in it. Here's what was in the original CDI.  Amazingly simple. Here's my interpretation of what that poo poo is. It was verified correct by a real life engineering student. So don't question it.  I even mocked up a copy of it with a potentiometer on a breadboard, ready to try out when the engine is back together. But having done all that, I've decided to abandon it. Instead I've decided to build a new ignition system from scratch in a totally different design using an Arduino to make a fully software mappable ignition curve. Two reasons I wanted to do this. One, the stock magneto rotor on this bike is loving massive and loving heavy and has to be a big source of parasitic drag on such a tiny engine. Here's what one looks like taken apart:  It weighs like a pound or two. My other reason is that the reading I've done in multiple 2t tuning books suggests that 2t engines benefit from having totally nonlinear advance curves. The RPM compared with the combustion flame propagation must be considered, like a 4 stroke, but also it must be considered that at different RPMs the fuel/air charge in the cylinder will be of varying quality due to the gas flow between the top and bottom end, the shape of the exhaust, etc., and will therefore burn at different rates. Sometimes the air/fuel will be diluted with exhaust gases which weren't evacuated totally from the last combustion etc. So I will set up a transistorized system with no magneto, running on a total loss battery, probably some small lithium thing. It will use a crank position sensor from a BMW K bike, because it uses a hall effect sensor for easy reading at the arduino and because it happens to be of a shape that lends itself to attachment to the side of the crank on this thing. More pics of this will come. Also, got all the supplies I need to hydroform the exhaust. Got some 20ga steel sheets and some weldable attachments for a pressure washer. Once the bike is all back together, I'll be trying and failing several times at that. I have enough sheet metal to make like 8 exhausts, I hope that's enough. Meanwhile, a fiberglass guy I know through the racing club is making me a custom fairing tank and seat. Here's a progress pic with the bare frame.  Oh and I got some of these cause I heard they're the poo poo. 
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Jan 16, 2016 04:25
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Yeah to be honest I may have been a bit shortsighted on the Arduino and sensor rates. I just went Arduino because that's the only thing I knew was software programmable with minimal fuss and is small and would accept simple 5v sensor inputs etc. I don't know what it's capable of in terms of refresh rates.ReelBigLizard posted:Please share any work on that Rev. I'd be interested in building something similar when I rebuild my Bantam. Ripoff posted:The custom ignition thing is cool as hell and you need to update on your progress with it. Stupid question, though and I think you covered it before but I'm an idiot and can't search to save my life - what's the redline on this thing? From what I remember from playing with my arduino it's pretty easy to confuse it when things are happening fast, but for all I know it could be more than capable of handling 14k RPM in a 2 stroke motor.
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Jan 16, 2016 19:41
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Yeah I think I may leave that kind of work until the next big off-season upgrade. Still got a couple moderately big things to do before this season, and there's some low hanging fruit like aluminum rims that can be done whenever. I would love to be able to rev it higher and I would love to fabricate an aluminum trellis frame for it. Theoretically. Some day.
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Jan 17, 2016 00:04
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Yeah but is the rod strong enough? Piston strong enough? Needle bearings strong enough? How do I even know, without running it until it blows up? I'm not at RedBull Racing levels of financing such that I'm comfortable using that method. Maybe I should try calling TAG Heuer and Santander and see what kind of cash I can get, though. I worked up the Arduino code today for the thing. Been a long time since I wrote any code and never used an Arduino before. Wondering if it's inefficiently written enough that it'll cause processing speed problems at 12000rpm. Or whatever else might be wrong with it. Won't be able to find out until the top end comes back from the machinist and the frame comes back from the bodywork guy. http://pastebin.com/iiVKc4ps
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Jan 17, 2016 23:39
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Jim Silly-Balls posted:To your point, I don't know how much force your piston is exerting, but I'd have to guess that it's not a ton, and unless the bike uses the worlds worst bearings and conrod they're probably ok. quote:The deal with spinning fast is more around the initial trueness of the crank and its ability to stay true under those kinds of high speed. Collateral Damage posted:What Arduino board do you plan on using?
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Jan 18, 2016 01:59
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Collateral Damage posted:There are probably some people over in the Arduino thread Jim Silly-Balls posted:All this being said, and keeping in mind your limited race budget, have you played with pipe design, porting and gearing to try to get more out of the stock rev range and crank? Look at the intake length and maybe put a boost bottle in there to try to get more from a longer intake length?
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Jan 18, 2016 15:44
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Jim Silly-Balls posted:Boost bottles help a lot to cure flat spots in the powerband. If the ysr came with one I'd imagine your bike could see benefit from it as well. EX250 Type R posted:http://www.ebay.com/itm/331747012070
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Jan 19, 2016 20:28
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Yeah I'll be having charts and all kinds of poo poo to post. Hopefully before too long but I dunno when exactly I'm getting my frame back (machinist is nearly done with the engine parts) and I have no clue how hard it'll be to make an exhaust pipe or get the ECU working. I looked for RF shielding on Amazon and most of it came from a company that made a metal mesh knit winter hat to keep the Zionist Occupation Government's chemtrails out, so I'm not sure I trust anything else they're selling to actually protect my arduino from spark noise. Edit: Prototyped up the relay circuit to attach the arduino to the coil. I think I should write another bit of software just to test if this thing can reliably make a spark on its own before I go so far as to hook it up to an engine and see if it can time a spark properly at 12k rpm.  Edit: https://www.youtube.com/watch?v=e-OapQKEzkY Rev. Dr. Moses P. Lester fucked around with this message at 03:09 on Jan 22, 2016 |
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Jan 19, 2016 22:17
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| # ¿ May 14, 2024 00:01 |
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Got the crank sensor ring mounted on the flywheel stub piece. Gotta get the sensor mounted on it now.  Luckily it'll fit inside the engine cover without cutting any holes in it so the engine will look stock from the outside. That's an unexpected bonus. Got the cut down cylinder back from the machinist and started dremeling the head to set up the combustion chamber and squish band. Here's measuring the squish band with bondo.   That's squish as gently caress yo. The edge varied from 0.011 to 0.014". 0.015" is the smallest you'd ever want on the smallest motor according to the books I've read. So I need to adjust it a bit. Then check the cranking PSI and carve the combustion chamber bigger if it's over like 160psi.
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Feb 13, 2016 03:26
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