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My baby, fresh from the last club day of they year has been waiting patiently for a good clean.

Went in the garage to start her and nothing.

changed the carb, plug, battery. Checked reeds, fuel , spark and jets. Still nothing.

compression feels good as I can’t turn engine over by hand. Took the plug out and turned key. Piston moving freely and has a good spark.

when I choke the engine, all the fuel fills up the air box. Any ideas brains trust??? 

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Hi Jamie it sounds to me like you need to replace the needle and seat in the carby.  They can get stuck / blocked and this often causes the fuel to end up in the airbox.  Hope this helps mate.

Cheers Dom, I change pd carbs and still got the same result. Checked the reeds weren't sticking closed as well. It's really got me stumped. Turns over like a trooper, just won't fire....

Dominic Albanese said:

Hi Jamie it sounds to me like you need to replace the needle and seat in the carby.  They can get stuck / blocked and this often causes the fuel to end up in the airbox.  Hope this helps mate.

Don't know how you can get fuel in the airbox unless you are drawing the fuel up by covering the holes in the airbox. By the time you get fuel in the airbox I would imagine the engine is flooded & you won't get spark to start. Try this. Take the airbox off. Put your hand over the carbie venturi (after taking plug out & rest on the head...engine you idiot! Turn back wheel just drawing up enough fuel to dampen your hand.

I was choking it Richard to see if fuel was going through - hence the fuel coming out rather than being sucked up to flood the engine. Plug wasn’t wet...initially thought the jets or maybe even sticky reeds. I’ve heard mention that I might have a ring stuck and messing up my compression. Will take it apart after Xmas...
When you crank it does it just blow atomised fuel out of the exhuast just pipe?

Before you tear the whole thing apart, first up remove the carby , manifold and reed block and make sure the reeds are all 100% there.  You cannot see the whole reed petals without removing the manifold from the reed block. 

Is the exhaust blocked up? My 2t dirt bikes refuse to run if the exhaust bung is in. I've also had mud wasps build nests in clubman and rotax exhaust ends and that prevents the engine from firing

Thanks. Checked and replaced:
Reeds
Carb
Battery
Exhaust
Plug
Have fuel going in and a decent spark.

However, taken cylinder and head off and piston ring looks seized in place. (Doesn’t move at all) Will try loosening it and see how I go. Looks primed for a top end rebuild...

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