'04 Kymco Super 9 loses power...

[BonneRocker]

So my Kymco loses power under load.
After warming up and trying to speed up, it bogs down to 10 mph and eventually dies, if held at wide open throttle.
I hear a reed-like sounding rattle/ sucking noise maybe. Checked air filter.
It does fine if I never want to go over 20 mph. Seems to shift fine at first but when going full throttle, bogs down. I can back off the throttle and limp it back home going slowly.
I have duplicated the problem over and over.
I seems ok at first, starts right up. Good gas, good spark, no other electrical gremlins.
It will rev strongly on the centerstand up to what sounds like WFO.

It seems transmission related.
I would appreciate any input? Thanks.

[kdude]

Sorry i can't help you but i'm curious cause that is a bike im test riding this week.

I hope you fiigure it out.

[ysr612]

things like that are almost always an air leak after the carb

[BonneRocker]

Would an air leak affect the low speed throttle also?
It has plenty of go at low speed but as soon as I open throttle fully, it slowly bogs down until it dies (if held open).
I can do on-off with the throttle and keep moving, but not over 10-12mph, maybe 15.

[ysr612]

Originally Posted by thumptastic

Would an air leak affect the low speed throttle also?
It has plenty of go at low speed but as soon as I open throttle fully, it slowly bogs down until it dies (if held open).
I can do on-off with the throttle and keep moving, but not over 10-12mph, maybe 15.

if it has just a flap that open up (in short a torn place it the boot between the carb and the head) the other thing to check is amout of fuel it is getting if the float is low or it fuel starved. if you pull the fuel line and it runs out slowly it will do this.

[BonneRocker]

I'm gonna drain float bowl, check diaphragm for leaks, check for clogged main jet, pull fuel line.
I'll report what happens.
Thanks a bunch.