2 Stroke Leaking Fuel

Message

back_marker · #1 Post by **back_marker** » Thu Aug 07, 2008 9:56 am

Having bought the wife (myself really) a little stinkwheel to play on and tinker with I am finally just about ready to get it on the road.

The biggest problem i have at the minute though is that it is losing fuel from the tank if left for a few days or so. Having scratched my head for a bit, it all became clear when I took the exhaust off and found that the expansion tank is full of the stuff, as is the crankcase so gravity has been doing it's thing and fuel is draining into the engine and then down into the exhaust when the bike is stood.

I know there is a problem with the fuel tap which I am in the process of overhauling but I believe i'm right in thinking that even with the fuel tap on, fuel shouldn't be running into the engine in this way, merely evaporating at a much slower rate through the carb vent.

Not got a massive amount of experience with 2 strokes but my thoughts are that if the float valve was not sealing and the vent from the float bowl were blocked that would cause this problem as the bowl would overflow through the jets and down the intake into the engine.

If anyone has any other suggestions they would be most appreciated

scorpio24v · #2 Post by **scorpio24v** » Thu Aug 07, 2008 10:50 am

only way to fill crankcase with fuel is, leaky fuel tap into not sealing float needle valve through jets into engine, depending wher in the stroke the piston is either crankcase or top of piston, (on a piston ported two stroke) or just crank on a disc valve. So i would say you are on the right track. Put in a new tank tap and the problem will evaporate

back_marker · #3 Post by **back_marker** » Thu Aug 07, 2008 12:21 pm

That what I thought but easier said than done as according to mr Haynes Manual, the fuel tap is not repairable.

I think the carb needs a good clean anyway so will take the plunge and see if i can repair the fuel tap with an o-ring kit at the same time.

Good to hear that you agree with my diagnosis anyway.

#4 Post by **Kwackerz** » Thu Aug 07, 2008 2:02 pm

It's fekked..

Seconded/Thirded on the Tap and Float. Both easy to fix.

back_marker · #5 Post by **back_marker** » Thu Aug 07, 2008 5:26 pm

Good news is fuel tap was an easy fix - simply disassemble and reassemble correctly unlike the previous owner.

Bad news is I have the carb in bits so there are two possible outcomes:

1. Everything is perfect

2. Fuel tap is great but will no longer run due to excess of 'wing' nuts and assorted little bits missing from carb.

My money is on number 2

#6 Post by **Kwackerz** » Thu Aug 07, 2008 5:58 pm

The float isnt bent so it doesnt sit properly when fuel is in the chamber?? Unusual but possible if it's been played with before..

*coughs onto back of hand*

There was this Capri once......

*walks of sheepishly*