If you hold the throttle in a steady position does it stumble rythmically, or is a random popping and sputtering? If it's a steady pulsing stumbling the problem is probably somewhere in your electrical system.

 

I have already swapped out my boxes it seems a little better with the stock box but doesnt fix it . and I took the carb back to how it ran right and it makes no difference here is the odd thing I can jet big like 160-165 the bike smoked black smoke for a second then after that no smoke at all.

 

recon it is random the lower off of idle the less it pops, if you speed up throttlethe pops get more frequent and more erratic then once you hit a little over quarter throttle it seems to be fine. I can nail it off the line and as long as I dont let rpm get too low off the get go it will run hard thru every gear

 

If you put the air box lid back on, does the popping and backfire go away? If it does, then you dont have an electrical problem. That should richen things up alot.

 

no the poping doesnt go away with the lid on. I just tried a few other things and came up with another thing that may help. when I rev the bike for a few seconds the reverse light will begin to blink. now I know that sounds like a e brake problem but I have cleaned it also took it loose and grounded none of which makes the light go off. you can put it in gear and the light will go off. then if you put it back in nuetral and rev it the light begins to blink again. but still this doesnt seem like the problem to me. is it possible for me to have an extreme lean bottom end,and if so what would have caused it,and do I need to go up on pilot?

 

If there was a problem with the carb it would be the idle/pilot circuit. That's what controls the ratio from idle up to 1/4 throttle, where the needle takes over. Did you take the pilot jets out and make sure they're not clogged up?

 

yes I took them out and they were fine,is there any way that I would need to step up pilot jets ,could that be my problem?

 

I think if the pilot jets were too small it would have been acting up right off the bat, not 2 hours into riding, but if you're still running the stock pilots it wouldn't hurt to bump them up a few sizes and see what happens.

 

My Raptor just did basically what you are describing as it has in the past and here is what i i do to fix mine.On the left hand side of your motor under the frame there is a small black connection that pops into place onto a brass post .If you remove the connection and clean the inside with a q-tip or something similar i think you will cure your problem.I must not have read that your reverse light was coming on because i would have suggested this fix to begin with.I would bet that this is it.

 

anyone know why else the reverse light would blink,I cleaned it and it still blinks after a short 1/4 throttle rev. I also grounded the wire like the bypass mod says and the light still doesnt go off. and it still pops.I like to think I am a good mechanic, but man this prob. is getting me and my dad,both of which have built race motors all of our lives. I only have two more things I think it could be you guys tell me what you think, float level to low starving pilots on take off? or pilots too small since the change of exhaust. the only other possabiliy I can think of is burnt valve or bad valve timing. has anyone ever taken the air ducts off the back of the carb to see if the vaccume slides were going all the way up? well I did and they went all the way up but gas was spraying out the back of the carb which sounds like a valve prob. but this could be normal in a single cylinder engine, who knows. If I cant figure it out soon IM calling doctor house!