| Author | Message | ||
     Dwardo |
Last night somebody told me that my bike was leaking gas all over the parking lot. Sure enough, gas was running out the carburator "drain tube". I'm assuming some crud got stuck in the float needle and because I didn't shut off the tap it ran out. My question is, how does it get out there? I would have thought it would run out the float bowl vent if it got high enough. The shop manual refers to this tube as a drain tube and says something about it being for draining the float bowl but doesn't say how you would do that. I don't want to remain mystified until I can take the carb apart and clean it so I thought I'd ask. Also, some gas ran onto my drive belt. Can that damage it? I think it has done this before as it explains a mystery stain on the shock, although I've never seen it leak anything before even in the garage. Also, I'm concerned that some gas may have entered the crankcase and diluted the oil. It's time for an oil change anyway but I had no choice but to ride the bike home, about 5 miles. Has anybody successfully used an in-line fuel filter? I use them on the Norton and they catch a lot of crap but it doesn't need as much fuel flow and it's got two fuel lines. I think I will take the carb off and clean it and install the pilot jet and intake gaskets I bought earlier. It's just been running too good to fool with up until now. Anything else I should do while I'm in there? Thanks. | ||
| Mikej |
Any time my bikes are parked for more than 30 minutes or so I turn off the petcock (except when I forget or didn't plan to be there for that long). Gravity never sleeps. How many miles are on the bike? Might be a good time to check the intake seals. There is also the a/f ratio screw you could remove the plug/cover off of and play around with that as well, details are documented in the KV carb section someplace. Also re-route your rocker box breather tubes if you haven't done it already, where you route them to is up to you, or just convert the bike over to XB style rocker boxes. At this point the mission creep syndrome creeps in and things start to get out of hand quickly. Maybe it's best to just keep riding it and turn the petcock off until the snow begins to fly and the roads begin to ice over.  | ||
| Mikej |
Okay, I can't easily find the magical page that used to give all the good carb settings at the top of it. Hopefully someone else will be able to find and link to it. | ||
| Jayvee |
"Anything else I should do while I'm in there?" You mention changing the "pilot jet" (Slow speed jet?) have you adjusted the Idle Air Mixture screw? It comes hidden under a soft metal plug in the bottom of the carb. Should be screwed out about 2.5 turns from fully seated in, you sort of tune it by the sound of the idle, so this is after re-assembly. Maybe change the float bowl screws to allen head screws? Lube the throttle cables? Oil your K&N Air filter? (Doesn't everybody run one of these?) | ||
| Dwardo |
I'm shamelessly bumping this back to the top. What I really want to know is: 1) If the needle/seat are leaking, by what means does fuel get out of that overflow tube in the bottom, and 2) Is this common and what are the usual fixes, other than cleaning the carb. I'd like to install an in-line filter but don't know if it is a good idea. Thanks. | ||
| Chasespeed |
1) If the needle/seat are leaking, by what means does fuel get out of that overflow tube in the bottom, and 2) Is this common and what are the usual fixes, other than cleaning the carb. I'd like to install an in-line filter but don't know if it is a good idea. Thanks. Honestly, its common on just about EVERY carbed bike I come across... Leave the fuel on, and it will start to fill up, and then overflow.. As mentioned, every time you are gonna be away from the bike for more than a few minutes, shut the fuel petcock.. Just change your oil when you get chance, and remember to shut your fuel off.... Chase} (Message edited by chasespeed on October 04, 2007) | ||
| Road_thing |
Dwardo: I think the float bowl overflow is directed into the tube via an internal drilled passage. I've had pretty good luck in this situation by just dropping the drain plug in the bottom of the float bowl and flowing some gas through by opening the petcock briefly--it seems to flush out whatever crap is holding the float needle open. I run Mikunis on my bikes, though, and I don't remember for sure if the stock Keihin has a drain plug on the float bowl or not. If it's got one, that's what I recommend. Be sure to catch the gas in a can or a rag or something--it's a major fire hazard. rt | ||
| Jayvee |
Yeah, drain plug accessible from the back, you need a real long small screwdriver. It empties the float bowl out the little black over-flow tube. Get a catch pan, and no smoking! I've done this on other bikes where I just took off the bowl and push (very gently!) on the float up and down, and it cleared out something and made the dripping stop. But I've also had to remove carb and take out the float needle thing to clean it. That's the most-likely worst case. It is possible for the floats to need adjustment, or even go bad, but this is pretty rare. | ||
| Djkaplan |
I think there is a weird situation with these Keihin carbs and the overflow tube. I looked at my overflow tube, and the internal passages don't seem to lead anywhere. I think the overflow tube is vestigal and requires an earlier float bowl to work. Or something like that... I had a float stick once and do the same thing. It didn't overflow through that tube at all. | ||
| Dwardo |
Thanks. It was coming out my overflow tube big time so it must be connected somewhere. If it had been coming out the float vent then I should have seen some dripping from the airbox, I would think. Everything was dry except there was gas flying out of the tube. I didn't have any tools nor even a rock to beat on the float bowl so I waited for it to dry up after turning off the gas and started the engine, figuring the vibration might shake whatever was in there out. It worked and didn't give me any more trouble but I have not ridden it since I got it home and won't until I change the oil. The Norton is sitting there looking down its nose at the Buell just now and sticking its tongue out. |
