I never really thought about before but with my recent problems I'm wondering: is the tank on the '95 m900 supposed to be air tight? I'm thinking not and there has to be at least some kind of venting going on otherwise a vacuum will develop in the tank and fight against the fuel flow. If there is a vent hole, is it reachable so that I check it to see if it's blocked? I blew air into the fuel output with the gas cap down and it built up pressure instead of venting anywhere. That doesn't seem right to me. I also used to be able to drain my tank w/ the cap closed but now it will gurgle like a water jug if I don't open the cap.
It should be vented. The vent is probably in the cap, but I've never messed with one of that era.
The only thing I can think of is that the 2 overfill holes just under the cap seal double as vents. It makes sense that those holes should lead to the same outlet as the spill hole in top cap area but if I blow air in through overflow outlet at the bottom of the tank and plug the spill hole in the cap area, no air comes out of those 2 overfill holes. Maybe I'm chasing something that isn't a problem at all. I did have my tank rust coated but I have been riding it for at least a thousand miles since then w/o problem so I don't see how that could be the problem.
If you look at the cap you will see a small hole in the top. You will also see a piece if rubber with a hole in it that lines up with that small hole. This is your vent. What you don't see is in the cap itself is a check valve. If you are developing a vacuum either the vent is clogged/jammed or the hose that used to go to your charcoal canister is restricted. If you remove the rubber piece under the cayout tank will vent. This is not a good repair though. Raise the tank when fairly full and fuel will pour out.
Wow there are a lot of tiny parts for you almost lose when you take the cap apart. I don't see anything wrong with it but what do I know. Is it possible for the charcoal canister to clog up? Feels like I've looked at everything I can and it's time to put it back together and see if it still acts up.
Oh yeah, if the hole that goes to the charcoal canister is supposed to be the vent, does that hole connect w/ the overfill hole? I'm still confused how that doesn't seem to connect to anything right now.
Yep, the canisters clog over time. I assumed yours was long gone. The vent and overflow do not connect from the factory. Loose the canister, there is a tutorial in "tutorials" somewhere.
Nope, still got it. Never done anything to it, lol. Alright. If If this isn't good to go right now then I know what I'll be doing next. Thanks a ton, Howie.
Hmmm.... I went out to start up the bike and it seemed ok at first. Then it bogged down while just sitting in my garage warming up. When it died I saw smoke coming out of the right exhaust. Left exhaust had nothing and was much cooler than the right exhaust. :-\ It's a very light smoke like from a cigarette. I'm lost now. It doesn't always seem to do that. It seems to start up fine but it doesn't want to idle and if i run choke it dies. I suspect that if it warms up it'll be alright but I'm nervous about the smoke.
The 'smoke' is most likely water vapor and is not a problem
My monster has more coming from one pipe than the other.
Does it also smoke slightly if it's running lean? My original problem was that I dropped a cylinder probably because it was running too lean.
Quote from: erkishhorde on September 12, 2011, 05:10:05 PM
Does it also smoke slightly if it's running lean? My original problem was that I dropped a cylinder probably because it was running too lean.
not in my experience
Seems to run fine. Made a short run a couple freeway exits down and back w/o problems. No sign of vacuum in the tank. Time to do an oil change and then make a longer run. Thanks for all of the help.