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And come on Lambretta hasn't existed in 45 years
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Sep 27, 2017 19:54
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Current Guzzi owner trip report. First year & 7,000 miles were lovely. Mile 7,289 saw an oil leak in the final drive. Haven't ridden it in two weeks. Dealer has had it since Friday. No word yet on when I'll get it back. Going through withdrawals, watching a lot of videos about Africa Twins on Youtube.
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Sep 27, 2017 20:55
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GnarlyCharlie4u posted:Bring it over and we could make one. Like everyone else I have done bottom ends, top ends, rewired entire harnesses and all kinds of other fun project poo poo, but I will never again attempt to mount my own tires. Taking the wheel and new tire to the shop and returning a few hours later with a credit card in hand beats hours of cursing, throwing tire irons and general frustration any day.
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Sep 27, 2017 21:25
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Gay Nudist Dad posted:And come on Lambretta hasn't existed in 45 years They're still putting out scooters to this day (although they've been generic Chinese ones rebadged since 2011, they *still* all have the special "You don't actually want too close a connection between the axle and the wheel, do you?" front wheel bearings)
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Sep 27, 2017 22:05
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GnarlyCharlie4u posted:Bring it over and we could make one. Also get no mar’s tire changing lube. That stuff is good.
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Sep 27, 2017 23:23
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Thanks for the info on Guzzis. Will keep them on the bottom of the list for the moment.
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Sep 28, 2017 00:59
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goddamnedtwisto posted:They're still putting out scooters to this day (although they've been generic Chinese ones rebadged since 2011, they *still* all have the special "You don't actually want too close a connection between the axle and the wheel, do you?" front wheel bearings) I mean... there are scooters being sold as Lambrettas, yes, but you can't trace any sort of continuity between the Italian scooters of the 60s to the bikes on market today. The name has changed hands many times. Calling a new Lambretta Italian is even less true than calling a modern Mini British.
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Sep 28, 2017 03:28
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predictive posted:Like everyone else I have done bottom ends, top ends, rewired entire harnesses and all kinds of other fun project poo poo, but I will never again attempt to mount my own tires. Taking the wheel and new tire to the shop and returning a few hours later with a credit card in hand beats hours of cursing, throwing tire irons and general frustration any day. I agree. However I think that in this particular instance it's less about the convenience and more about the learning. Everyone (especially dirtbike owners) should know how to change a tire, even if they only do it once. I don't work at a shop anymore, so now I just take my wheels in to have tires swapped. However, I've had a flat and had to swap a tube on the side of the road and was plenty glad that I had the ability to do it. builds character posted:Also get no mar’s tire changing lube. That stuff is good. This might be the best advice anyone could ever give. That poo poo is magical.
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Sep 28, 2017 16:48
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Alright I'm getting sick of my bike stalling. How do I find the air leak? The shop I was at told me to spray some carb cleaner to find the leak and my rpm will rise. Google says carb cleaner will lower rpm. Am I misremembering what he told me to use? I suppose carb cleaner could still work though.
Schroeder91 fucked around with this message at 00:57 on Oct 3, 2017 |
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Oct 3, 2017 00:54
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Schroeder91 posted:Alright I'm getting sick of my bike stalling. How do I find the air leak? The shop I was at told me to spray some carb cleaner to find the leak and my rpm will rise. Google says carb cleaner will lower rpm. Am I misremembering what he told me to use? I suppose carb cleaner could still work though. Ethanol.
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Oct 3, 2017 01:07
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Spraying something flammable (like carb cleaner or starting fluid) around the carburetor boots will cause the RPM to rise if there's a leak, because the fluid will be sucked into the cylinder through the leak and burned, just as if you'd cracked the throttle a little bit more. I don't know why it would cause your RPM to drop unless it was somehow both leaky and running extremely rich. You can't trust everything you read on the internet.
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Oct 3, 2017 01:11
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The go-to vacuum leak checking fluid is nitroglycerin, schroeder.
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Oct 3, 2017 01:41
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If it changes the RPM at all then that's a positive test result, you're just trying to find where the leak is. It might lower the RPM if somehow you managed to spray too much crap in there.
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Oct 3, 2017 01:47
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That's what I figured as well, whatever helps identify the problem.
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Oct 3, 2017 01:58
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Lean engines that are sucking air tend to idle high, spraying carb cleaner will lessen the amount of air getting in, lowering the idle
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Oct 3, 2017 02:07
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Ah well my idle is fine the issue when I pull in the clutch lever my rpm tanks and sometimes it stall, sometimes not. Started happening after I had removed the boots and hoses and stuff and put it all back together. So something could be loose but I think it'll be this hose that's old cracked up. Probably bent and broke through when removing it all.
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Oct 3, 2017 02:14
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Is there some sort of convenient conversion for compression ratio to an approximate compression tester value? I'm shortly going to be in a situation where I know the compression ratio but don't know what sort of PSI reading is healthy. Yes, I know it's the difference in values that matter and leak down test and blah blah but just stop being pednatic and humour me.
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Oct 3, 2017 05:13
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Well assuming the intake air is at atmospheric pressure, you could just multiply the compression ratio by the local pressure, right? 14.7 psi at sea level, and your local airport will give you a more accurate figure. 14.7 * a compression ratio of a little above 10:1 sounds like 150 to 180 range that you often see specified. That figure should be the theoretical maximum value you'd see on the gauge, and you decide how far below that you'd be willing to accept.
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Oct 3, 2017 05:18
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Yeah so from what I can work out using the classical greek method of thinking really hard about stuff without testing anything practically, the cam duration would play a part so as to make that impossible. Engine has 11.1:1 compression. 11.1 x 14.7 which works out to 167 psi and I remember my 350,000km 80's BMW with factory fitted 10:1 compression was healthy for having 220psi. Something else is happening here. e: wait, maybe that was 180PSI? I can't believe my carefree years of doing stupid poo poo with eurotrash in my driveway were a loving decade ago. e2: I went back through my old notes and looked it up, I was getting between 170-180psi on a 10:1 compression engine built in the 80's, designed in the 70's Slavvy fucked around with this message at 05:53 on Oct 3, 2017 |
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Oct 3, 2017 05:22
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The cam duration shouldn't enter into it. There's only one part of the stroke where it's compressing, and that happens when all the valves are closed, unless you have a Miller cycle or some bullshit like that. If air comes in at 14.7 psi and fills a cylinder with a volume of e.g. 300cc, and then it is compressed down to a volume of 30cc at TDC, and everything else remains the same, Boyle's Law says that the pressure will increase to 147 psi. However, I just remembered that there will be significant heating due to the compression, which makes this a more complicated question since the additional heat increases the pressure more. So I calculated it as an adiabatic process (no heat lost to the surroundings) and concluded that compressing air 10:1 results in air with a temperature of 462 C and a pressure of 27 atmospheres (~400 psi). Clearly adiabatic compression gives values that are too high, which makes sense given the thermal mass of the cylinder, which will suck some of that heat away. so basically at this point I have no idea other than to tell you it's gonna be more than 147 psi but less than 400. Helpful!  If you could figure out what the final temperature of the air is after accounting for both compression and heat loss to the cylinder walls, you could easily come up with a figure from the ideal gas law (PV = nRT).
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Oct 3, 2017 06:50
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I always thought timing overlap can affect comp ratio.Sagebrush posted:The cam duration shouldn't enter into it. There's only one part of the stroke where it's compressing, and that happens when all the valves are closed, unless you have a Miller cycle or some bullshit like that.
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Oct 3, 2017 17:31
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Compression ratio is calculated geometrically, so nothing apart from the piston's swept volume + combustion chamber counts. Sagebrush nails it, only thing I might add is that a cylinder probably doesn't fill to exactly outside pressure. Also, I wonder what the pressure is during combustion.
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Oct 3, 2017 18:01
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clutchpuck posted:I always thought timing overlap can affect comp ratio. Timing overlap happens on the exhaust stroke, which doesn't matter for calculating the engine's effective compression ratio. Timing lead or lag would have an effect, though. By the time we're halfway through the intake stroke, the intake valve is fully open and the exhaust valve is fully closed, so air is streaming in at ambient pressure from the intake. Near the bottom of that stroke, the intake valve begins to close. Sometime around BDC the intake is fully closed, the cylinder is full of air at ambient pressure, and compression begins. If the intake valve remains slightly open for the first few degrees of the compression stroke, that would reduce the effective compression ratio to (cylinder volume when the valve closes / minimum cylinder volume). However, that would also cause some of the charge to be forced back out into the intake tract, which the engine designers obviously would be trying to minimize. Also, I just thought of another factor: the adiabatic heating will cause the fuel droplets to vaporize, increasing their volume massively and therefore increasing the pressure in the cylinder. Factor that one in there somewhere. Ola posted:Compression ratio is calculated geometrically, so nothing apart from the piston's swept volume + combustion chamber counts. Sagebrush nails it, only thing I might add is that a cylinder probably doesn't fill to exactly outside pressure. Also, I wonder what the pressure is during combustion. There are undoubtedly fluid-dynamic effects that make the cylinder fill at slightly different pressures depending on engine speed, but I am not enough of an engineer to work those out at all. You can work out the pressure during combustion (in an ideal world) by determining how much fuel comes in, calculating the volume of exhaust gases that are produced, calculating the energy produced, working out how much that will increase the gas temperature, and plugging everything into the ideal gas law. Assumptions include: a perfect stoichiometric ratio of fuel to air in the charge, complete combustion of the charge into only CO2 and water, instantaneous combustion of the entire volume at the moment of ignition, no heat loss to the cylinder. Theoretically you could also go backwards and make a reasonable assumption of cylinder pressures from the engine's torque at the crankshaft, given an RPM and torque figure, but I believe you'd need calculus to integrate over time and I haven't done calculus since I was in grad school.
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Oct 3, 2017 18:29
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Sagebrush posted:Timing overlap happens on the exhaust stroke, which doesn't matter for calculating the engine's effective compression ratio. Its been a while since school for me as well, but I vaguely remember that it can. Something about how a piston doesn't (always) sweep the entire volume of the cylinder, thus there is "dead space" between the piston at TDC and the head. This dead space is not considered for compression ratio, however timing overlap can effect how that space is used, thus you can end up jamming extra air in there somehow, thus increasing the effective compression ratio. Or so I recall. I probably forgot some specific detail that actually makes all of that rambling make sense.
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Oct 3, 2017 20:29
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Brigdh posted:Its been a while since school for me as well, but I vaguely remember that it can. Something about how a piston doesn't (always) sweep the entire volume of the cylinder, thus there is "dead space" between the piston at TDC and the head. This dead space is not considered for compression ratio, however timing overlap can effect how that space is used, thus you can end up jamming extra air in there somehow, thus increasing the effective compression ratio. Or so I recall. I probably forgot some specific detail that actually makes all of that rambling make sense. It's absolutely considered in compression ratio, but not in displacement. If you have a thinner head gasket (all other things remaining identical) the only thing that changes is your compression ratio. Also, when you're doing a compression check, you're not sucking in (much) fuel, if any, and you're compressing the air so slowly that it absolutely is not an adiabatic process. C.R. x ambient pressure ≈ maximum pressure in cylinder.
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Oct 3, 2017 22:51
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Taking the fuel line off the fuel valve on my '04 Honda 599 has gotten very, very, very difficult in the past few years. It seems to almost weld itself onto the fuel valve and due to limited clearance it's really hard to get in there to pull it off. What's a good way to make this easier to take off in the future? I worry if I have to pull the tank off on a road trip it's going to be almost impossible, it took 20 minutes of fiddling to get it off in a dry garage stocked with tools. My thought is it's old fuel line that's had tons of ethanol gas through it and it's probably time for a new line: it's a whole $8 for a new OEM one.
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Oct 5, 2017 21:19
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Yeah just replace the line. Rubber gets hard and stiff as it ages, regardless of ethanol gas or whatever. In addition to making it hard to remove from the fitting, that means it's gonna be more prone to cracking when you do. A new line will be nice and soft and flexible. If it's getting "welded" onto the fitting there may be some varnish build-up in there, but it's probably just that the rubber doesn't stretch any more.
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Oct 5, 2017 21:23
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I always just go to my local auto part store and buy a foot of automotive fuel line for about $3 when I'm in need. That way I can make it just a little longer than stock (easier to deal with removal/reattachment), and have extra for making bushings, future replacements, emergency repairs, etc. There's also always a good supply of various types of hose clamps that will fit.
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Oct 5, 2017 22:14
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HenryJLittlefinger posted:I always just go to my local auto part store and buy a foot of automotive fuel line for about $3 when I'm in need. That way I can make it just a little longer than stock (easier to deal with removal/reattachment), and have extra for making bushings, future replacements, emergency repairs, etc. There's also always a good supply of various types of hose clamps that will fit. This. I also have a length of line to use as a finglonger for threading spark plugs.
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Oct 5, 2017 22:38
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clutchpuck posted:finglonger A+ reference Also good tip
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Oct 6, 2017 03:50
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What's the best approach with sales people at motorcycle dealerships if I *just* want to test drive some different bikes, but don't have plans on buying for months, maybe a year?
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Oct 6, 2017 16:08
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What dealerships? I couldn't get a test ride on a tenere, africa twin or ktm 1290 super adventure even when I said I was going to buy that day. From everything I have read this is normal for japanese bike dealers. BMW volunteered the test ride before I even asked. It was a combo BMW/Harley dealer and I think they would have let me ride a harley just the same.
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Oct 6, 2017 16:35
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Try to find a demo day close to you. It's been my experience that US dealerships won't allow test rides for new bikes unless they are Harley. There are outliers, but I myself have not had the pleasure of any dealer that would.
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Oct 6, 2017 16:38
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I don't usually have problems scamming demos at dealers. The Ducati dealers seem particularly interested in throwing keys at me.
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Oct 6, 2017 17:16
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So the triumph dealer did not let me test drive, and the Harley dealer did. Hrmm... 
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Oct 6, 2017 20:46
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Dumb question...2015 Yamaha SR400 here. My ignition has gotten really gummy, its difficult to turn off and on and pull/push the key in and out. Anything I can do to smooth that out?
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Oct 6, 2017 22:02
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Spray some kind of lubricant. Silicone spray, white lithium grease, PTFE dry spray... WD-40 isn't a lubricant, but it might dissolve any kind of build-up that is forming in there... chase it with a lubricant. The ultimate lubricant for that kind of thing is graphite powder, but it's messy and difficult to use. Expensive too, if you don't want to just grind away at the center of a pencil. Slide Hammer fucked around with this message at 22:38 on Oct 6, 2017 |
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Oct 6, 2017 22:36
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I'd just shoot it full of WD-40, yeah. The stuff works as a mild solvent and lubricant as well as an electrical contact cleaner.
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Oct 6, 2017 22:45
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Slide Hammer posted:Spray some kind of lubricant. Silicone spray, white lithium grease, PTFE dry spray... WD-40 isn't a lubricant, but it might dissolve any kind of build-up that is forming in there... chase it with a lubricant. http://www.acehardware.com/product/index.jsp?productId=1275034 Would something like this be appropriate? This kind of product seems to be the internet consensus. EDIT: Ended up going with this: http://www.acehardware.com/product/index.jsp?productId=1425217 will report back epsilon fucked around with this message at 23:23 on Oct 6, 2017 |
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Oct 6, 2017 22:46
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| # ? May 16, 2024 20:26 |
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The graphite-infused lock fluid is a good choice... it's tough to get it where you want it to be when you have those tubes that are 98% air and 2% dry powder. One wrong squeeze and it shoots a cloud of graphite all over your controls.
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Oct 7, 2017 03:06
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