Completely stock 87, LRD pipe, open element K&N and 41.5 carb with the air screw 1 1/2 turns out. Original jetting was at 55/178, which I felt was a little too fat, so I backed off to a 52/172. Down low was Ok, nothing great, but it fell on its face big time on the top end, so I threw in a 180 and it picked back up on the top end. However there is a flat spot between low and mid range where it feels "boggy" and has no "pop" to it. Futhermore, on the shift between 3rd and 4th it falls out of the powerband for just a second, I thought this to be the gear spacing that the 87s have, but I could be wrong, any thoughts?

 

To me it sound's like the air screw,but where is the needle clip set at?Is it a Mikuni or Keihn?

 

Keihn, and 2nd position. What are you suggesting for the air screw?

 

Go to the Duncan Racing web site and they have a killer tech article on keihins. I used it this past weekend and my quad runs the best it ever did. doesn't miss a beat. From my experience the 500's like to run a little fat especialy on top. Good thing with a keihin that is 3/4- full all that goes into effect is the main jet and NOTHING elese. No idle screw or pilot screw. That's lower rpm stuff so it helps weed out that part of the equation. I would go into more ,but the atricle explains it much better than I can this late at night.

 

richen the needle 1 clip