HELP! 07 300 Fresh, but not right
 

I am the original owner of a 2007 EC300. This has always been an extremely reliable bike. Never even fouled a plug. I just installed a new piston, gaskets, and reeds. I heat cycled it after it was rebuilt, and no hint of an issue. Then the first time I went to ride it, after a few minutes it died like it had ran out of fuel. After this happening a few times I called it quits and made it back to the truck. I brought it home and tried making carburetor adjustments. Test riding it, it would die at WOT. I?ve inspected the power valve to make sure it is free and smooth. Currently it is running very rough and won?t idle.

I am now at a loss. Please advise! TIA!

Thanks,

Josh

Piston installed backwards, rag in air box?

Piston
 

I?d like to think I wouldn?t have done something that boneheaded but maybe I did! Can you tell from this picture?

Looks good.
Ring groove pins face the intake.

Ok, if the piston was installed correctly then that shouldn't be the problem.

Good compression? How long did the bike sit before you did the work? Are you sure you tightened/torqued everything to spec? Did you possibly pinch an electrical connection when reassembling everything?

Ec300
 

It didn?t sit too long. I used some contact cleaner to clean the connections to the ?electrical box? under the seat.

Check all your wiring really closely. You might have something shorting out or a bad ground connection especially since you did mess with the electrical wiring.

If its recently had a top end,check your coolant level to eliminate any oring issue which might be leaching coolant into the combustion area.
Also drain fuel bowl on carb to eliminate condensation/stale fuel if it sat for more than a month or two.Any moisture in the bowl will cause rough running,missing when you open throttle etc.
Does the base gasket thickness match the old?
The powervalve can be inspected while running
Remove expansion chamber,remove RH pv cover,refit expansion chamber,start and open throttle,pv should sweep from start point to the stop freely as revs build

Obviously check your last work.

Pull the carb and check it is getting petrol consistently. Actually check on bike first . In line fuel filters are favourite for kinking petrol line.

It would unfortunate timing to fail now but your stator may give similar symptoms.

Hi,

Check the reeds position, a couple months ago i take the reeds out for inspection and cleaning, when i put everything together i misplaced the reeds position, and had similar symptoms, bike would not iddle and would run very bad. The reeds need to be aligned with the carburetor connector.

I hope this helps.