Some one plese help me / aprilia mx 125 not running right

[b0unt1 tw1ns]

Hi guys i bought a 2007 aprilia mx 125 after owning it for 2 days of riding it started spluttring and running really bad when i tried opening the throttle up a little , if i eased the throttle on it was ok until it hit around 8-10k rpm then it would splutter bad.

so i bought a full pistion , gasket set , fitted it , got it running after a while then come the test drive. The bike starts up ok and ticks over fine , when i go to off set i need to rev it alot to stop it the engine from dieing.

Ive noticed the power valve isnt working , could that have anything to do with it ?

Im also premixing it with putoline mx5 as i dont trust my autolume system.

If any one has any ideas i would be very greatful for you to share them kind regards Thomas

[Mikey CB500]

If your running premix imediately upjet all of the jets in your carb to compensate for the more viscous fuel mixture.

You should be changing main, idle and pilot jets and be going up by arround 5%-7% of the value thats in there now, i.e if your main jet is a 100 now you want to go to a 105-107

The amount of people that just take out the pump and premix and think its more reliable, its seriously not if you dont upjet immediately youll just starve the piston crank and main bearings of the correct ammount of oil, youll have a seizure very quickly if not a complete nackered crank and main bearings.

[b0unt1 tw1ns]

Ok i will do soon as mate u have any ideas why it may be running like shitttteeee , it was spluttring before i changed to pre mix

much appricated tom

[Mikey CB500]

Sounds like its getting to much air and not enough fuel. Either gummed up/blocked carb or possibly a split/cracked airbox or carb boot, blocked air filter etc etc.

Just a thought when youve rebuilt the engine have you tourqed down the the inner cylinder head? If not it may not be tight enough and also leaking? Did use new gaskets right?

More than likely either the powervalve blade is stuck in the cylinder due to being coked up badly or a snapped cable, both are regular problems with the rotrax engines.

[b0unt1 tw1ns]

Ill check every thing mate and keep u updated , thanks for the advice i really do appricate it man

[Mikey CB500]