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Posted by Matt K (89 SE 5spd) on July 16, 2002 at 19:04:14:
In Reply to: Bit more (Just general principles - I don't know Hondas well)> posted by David on July 16, 2002 at 16:46:41:
: we were just letting it idle (a friend was rebuilding the clutch master cylinder at the time), and we thought a 10min idle might cause problems just from the heat. another thing I just remembered, the fuel petcock doesn't shut off all them way, but if you shut the bike down, the carbs should stop fuel flow anyway, right? : ***Probably. If the fuel tap has two lines, one will be petrol and one will be vacuum. Petrol only flows if the engine is running, and providing vacuum. The fuel tap might have 3 positions: On = petrol flows if engine / vac is running, Res = Reserve again needs engine+ vac and Prime, which passes petrol without the need for the engine or vacuum ie just plain gravity feed. You’ll use prime for the first time after reassembling empty carbs. You may also need to use it when balancing the carbs, as the vacuum line has to be blocked. : But if you leave the bike sitting, the cylinders can get filled with enogh fuel that you need to pull the plugs out to lear it. : ***No. with the engine off, the vacuum switch will close off the fuel tap. However, even if you left the tap on “Prime”, you’d be unlikely to flood anything. Petrol flows into the float bowl, the float floats up and a needle valve shuts off any further petrol from getting into the carb. Exactly the same as a toilet cistern refilling. : Fuel filters are a good idea. If you get a bit of grit in the needle valve seat, it can hold it open an make for continuous filling, resulting in the carbs overflowing. Bad news, since alternators and starter moters are usually due south. Remedy id to disassemble and clean, or just give it a damn good thrashing. That'll shift it. :) (That actually does work) : You were close with the idea, though. Harking back to 1970s 2-strokes, you had to put the fuel tap to off when you had finished with it, because many bikes suffered fron leaks, and you could end up with extra petrol in the sump. And in them days, men were men and electric feet were a luxury. Lunging your full body weight on the kickstart would light up a healthy engine, and do incredible damage against an hydraulic lock… : Today we pulled all the float bowls off and cleaned them out (there was quite a bit of brownish varnish inside) : ***Yup after 3 to 4 weeks standing, any petrol in the float bowl will be non-flammable. Drain, refill on “Prime” and start again. : and we finished up the clutch and bled the lines, btu then it started raining, so we called it a day. : ***You’re welcome
Got it up and running well enough to take it out for a test ride today. As I thought (and you did too) a good thrashing cleared things up a lot. The only real problems left are: 1. that vacuum fuel shutoff you speek of (I found it and figured out how it works, thanks) doesn't shut off all the way, and we get a fair amount of really black oil dripping out of the drain holes on the mufflers. The oil in the crankcase is clean and new, so it's not coming directly from there, and it gets good compression, so I don't THINK the rings are shot.... any ideas on where this stuff is coming from? I was thinking it might just be crap that needs to get blown out over a few days of riding... I gues we'll see. Thanks again :)
: Thanks for the info man