well a buddy of mine and i went rideing our new HO's at the sandpits since hunting season was over and we had nothing else to do,well to make a long story short we raced them on the sand and on the asphalt and he beat me 4 out of the six times we raced.it was real close every time (within a bike and a half). our weights are like this i weigh in at 197lbs. he is at 210lbs. i have a extra rack extender and a front rack extender and he does not. could this weight diff be that much of a advantage? i have a k&n filter and he does not.could this k&n filter have leaned my bike out and that why it isnt as fast/? i pulled the plug after we raced and it was white and needs a larger jet. what do you guys think?

 

I have heard that for every four pounds you lose you gain one horse power.

 

I'm not sure what the rule of weight to horsepower is with 4 strokes but with 2 strokes it is 7 pounds equals 1 horsepower.

 

The difference could be due to belt wear. Even a slightly worn belt will effect performance. Do you guys ride in the same conditions with the same tires. Big tires in mud will wear a belt very quickly. Riding in the mountains in High (even though you may not feel an occasional slip) will cause the belt to run a little hot and become glazed. This also will effect performance.

Greg

 

I see you have vampire tires on yours. I would imagine that they are taller than stock. If that is so and your buddie has smaller tires on his, that would be the difference. Taller tires take more power to turn.

 

no i had on my stock tires on it at the time. would putting the k&n on it and leaning it out be the answer? im going to try the 155 jet tommorow.

 

If your spark plug is white as you stated then for sure this would deprive your machine of a little HP. Also if you ride with a too lean mixture you damage your engine. Upgrading to a richer jet is most likely the thing to do. Keep us posted.

 

Silverado,
Try to get a 157.5 and a 160 jet. I ran my 155 tonight, still white like the 152.5. I put the 160 in but I can't run any tests until tomorrow. I will let you know.

weetoots

 

Silverado: You could be like me having the Midas touch of s**t. There could be ten machines to choose from and I would pick the slowest in the bunch But I would also play with the jetting.

 

well this was with the stock jet.i wonder why polaris sends these HO's with lean jets in them??