hi, i have a aprilia rs125 2005 model full power 2 stroke road bike, it has developed a bog, i cleaned the carby out twice and no luck i've adjusted the air screw still no luck and i have changed the needle clip position still nothing

it starts easily hot or cold, but when i use choke it revs really good no bog with choke on

any help would be appreciated in fixing this italian beast:ride:

Check for air leaks around the intake manifold.

agreed, sounds like its drawing extra air from somewhere! otherwise id say rejet, my friends son has a kx65 and his bike was totally fine and all of a sudden it developed a bog and after all the usual cleanign of the carb etc, we found out it was due to the way the barrel wears, right at the top of the barrel the piston ring wears it away quicker than the rest, its a common problem with them, your best bet if all else fails is to find out if theres any common known problems with them i have an aprilia rs50 full power but have never had this problem so i cant help there

HUGHES00 said:

Hi ,
it sounds like you've narrowed it down to fuelling..,
as stated you may need to compensate for wear - jets are cheap and easy,

Charlie

I would have a look at the reeds, could cause that. Look for chipped corners (or an obvious broken reed).

If not that then I'd check the mag-side crankseal. I'm not familiar with that engine but most 2t mags are open to air, and can airleak at the crankseal.