Engine Hesitating SOund at Full Revs

[Splitpin2005]

My monster now has a weird thing that when i give it full revs down say a tarmac carpark i can here the engine kind of hesitating. Sounding like it cant hold the revs. Yet if i hold the trucks rear wheels in the air and hold the thottle to the max the engine screams away with no problems.

What going on????????????

 

[atom3624]

Possibly the high needle's a bit lean.
When you lift it up, there's no real load on the engine, only the moving parts.
When it's on the ground, that's different.

Check the plug colour - always a good indication.

What petrolil ratio are you using?
How fresh is the fuel?
Is your air filter clean?
Check there are no leaks from the carburettor.
Check the head and exhaust bolts while you're at it.

Al.

 

[Splitpin2005]

thanks mate. Will do all ya said. Gonna check that carb gasket to engine. Had carb off teh other week when it wouldnt go. Maybe not good seal now.

 

[RFan]

Something else to check is for up and down play on the crankshaft. It will indicate worn bearings/seals, letting air in at high rpm under load. Some side to side play is normal, but there should be no up and down play.