i have an 04 raptor 660 and i raced my two buddies this weekend, one of them had a troy lee predator with a slip on hmf and a rev box, the other bike was a 05 raptor 660 with a full hmf and all these bikes have k and n filters, the raptor is the same is my bike, he betes me by like 2 bikes and the preddy betes me by like 3 or 4, i think that i need a new piston or something because i drag alot, and im really good at it. by the way im am not using the snows and we are on sand.

 

You may either need to get a valve clearance adjustment, or re-jet your carb. When you pin the throttle is their any hesitation?

 

not really, just when i go on a hill it bogs out and i have to keep it revved out alot

 

Did your buddies have paddles or snows? Ask your Raptor buddy what jets/settings he has his carbs at and see how they compare to yours.

 

What gearing are you at ...stock is 13/40 ....and what size are your rear tires? My videos...Click here.

 

If they Rappy is anything like the DS, your clutches could be going out and you wont know it. your bike just looses power to the ground, But its not like your engine is going to WIND up like the 2 strokes do. If you race alot you should always keep a mindful eye on your clutches, and plan on changing them out more often then you think.






Bigger.

 

If it's bogging you may need to adjust your floats.

 

it could be any number of factors, but how many hours do you have on your piston?

 

alot

 

A bog on the hill means something is not correct.....be it jetting or something else. Whats your jetting and altitude?