Problem

R

Rabbitist

New member
Ok so first race of the season last sunday.. On the start line butterflies ready to rip.. Anyway first lap half way round a mate stalls at the top of a nasty hill climb..i was sat up his arse and ended up stalling half way up after half hour of trying to kick it off nothing so had to push a mile back to van over terrain that was boggy an barely ridable (not impressed) any way fuel tank off check for spark good spark fuels getting through..but when kicking the engine over it sounds a bit flat? Not as much compression there?? Anyone any ideas what to check next? Guna have the carb off and clean that out regardless but I don't think that is were the problem lies..? Its a counterbalanced engine in a2000 ec 250 any help would be extremely appreciated?
Cheers luke
 
compression gone a bit... broken reeds or piston rings?
check for scoring inside the cilinder through the exhaust hole.
 
Reeds are fine and rings are in tact/no scoring to end is only 12 hours old however I did find fuel in the flywheel case so I'm guessing the crank seal has gone on that side.. Would this cause it to just stop working?
 
Rabbitist said:
Reeds are fine and rings are in tact/no scoring to end is only 12 hours old however I did find fuel in the flywheel case so I'm guessing the crank seal has gone on that side.. Would this cause it to just stop working?
Click to expand...

Very well could cause a compression leak and low compression could and does cause hard or no starting. When you get the piston and rings out when you tear down, check the end gap on the rings. I don't know what the spec for a GG is but on most bikes anything more than .015 indicates out of spec rings. When you check the end gap, put the rings at the bottom third of the cylinder. Let us know what you find....
 
Before you go ripping the motor apart check one more thing.

Make sure that your slide is closing properly on your carb. If it was open a bit it will cause it not to start.

For example, this has caught me twice. After taking the bike apart and putting it back together, I routed the throttle cable wrong which caused some tension on it. I had to jump start it and it started wide open. Once I put the cable around the bars correctly it started as it should.


Good luck
 
I find it odd that it just konked out and that was that.

I'd personally be throwing a new spark plug in it. Pulling the bowl of the carb blowing them out, checking for shit/moisture in the bottom of the bowl., making sure the slide is where its meant to be etc. And then trying again. Did you try a bump start?

Give the engine a once over and make sure that no bolts have come undone. The crank case drain would cause a significant drop in compression.

Sounds like you might have identified it as being LHS main seal.

You said top end is fresh so I'd imagine rings would still be in spec. No harm in double checking but doubt this is the problem.

Try a bit of start ya bastard in the intake and see if you can get it to fire.
 
No didn't try a bump start.. Also once ive pulled the fly wheel and removed the stator can.i get at the seal that way and replace it?
 
Currently have the clutch off power valve actuator and crank gears and rhs seal looks in good nick and no play in mains at all up and down but should there be a slight rotary play with the gears meshing?
 
Replaced the lh crank seal today but still no joy she just won't start even after a new plug a carb clean slide/needle returns correct.. Any ideas? I seem to be finding fuel coming out the drain bolt at the bottom when I open it.. What would this indicate? The reeds looked ok but could they have failed.. Really havn't got a clue what to do now..
 
Is the plug wet after kicing it a few times?(drowning)
It has spark and gas, but it sounds like it's getting too much gas..
Airfilter ok? carb clean in all passageways?
 
Ive had the fly wheel off to replace the crank seal and the woodruff key from the crank to the fly wheel is fine.. there is a keyway for the outer generator thing that isn't used but that only powers lights etc .. Correct? How often do reeds go? Can they just go slack through wear..?i re built the reed block about 6 months ago with the same old reeds so don't know how old they are.. Also used blue (medium) thread lock on the little philips heads holding the reeds down.. Any more ideas guys? Hopefully we'll stumble across the cause.. Lol
 
Can anyone tell me why my bike would have a spark and fuel getting through but out keeps flooding..every time I open the crank drain after trying to kick out off fuel comes out
 
The excess fuel can only come from the carb. Maybe a combination of a faulty choke and a worn needle jet? You would need a failing float valve to get a grossly high level in the bowl and pass significant extra fuel.
 
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