Ok, it is an 02 Raptor and Just looking for some jetting help before the rappy comes out for the spring here. elevation is around 1000ft above sea level, 101mm 11:1 HC piston, kenz port and polish, full sparks x6 exhaust, k&N filter with NO lid, hotcam stage 2 cam, ferrea valves, currently running 185/190 main jet mikuni, 27.5 pilots, needles on 3rd clip.....havnt had much seat time on this last summer as it was only put together for a bit until the snow flew..everything seems to be running strong, no backfiring on decel, no stumbles up top, but one thing I did notice is if im cruising in say 2nd 3rd gear about 1/4 throttle it seems to feel like its surging, power on power off, just a tad......I also did a few other things to check jetting, I threw my lid back on which has no snorkle and 2 - 2" holes drilled into it..when I did this when I was really hard on the throttl near high rpm's it would start to die sputter and liek the power just cut out...I figured I was way to rich with the lid...so when I take the lid off it runs fine, but im wondering if I could even go down to say 180/185 with the lid off...im gonna try this I think, what are some signs of it being lean on the top end..thanks a lot

 

You will be close with the mains where you are now, you are also close to the max the stockers will flow without mods. The best way to get it perfect, on the dyno and get the air/fuel ratio right, no worries about running lean after that.

Gav

 

You will notice a BIG difference in performance if you install a set of 35 or 39mm FCR's....

 

try adjusting your richening your needle. Issues at lower throttle are usually the needle. Also, I had my bike dyno'd and it is a fine at the lower throttle positions, but sometimes turbulence with different airbox mods can cause what you are describing. I see power on and off sometimes like you are but the AFR according to the dyno was 12.5.

 

TTT

 

anyojne else?