Raptor owners with this problem...whats the fix? Non-Raptor owners...what do you suggest? My dealer has nothing on the Raptor yet (only sold 1...mine). It does'nt seem to be "weather change" related, since it happened once when the temperature was 75+ degrees and last night when it was about 50 degrees. All sensible replies are appreciated!

 

Gary,

I had my dealer to call the Yamaha tech line. My dealer followed their suggestion which was 1)Richen the fuel/air mixture with the mixture screws found up and under the carburetors and 2) move the needles 1 clip position higher.

It seems they think it is due to a lean mixture. Also, I've noticed it seems that the problem is intensified when the idle is set lower than factory specs.

My dealer also noticed that the airbox is fastened to the frame with slotted holes. He moved the box toward the carburetors so that the boots aren't always tugging away from the carburetors.

I haven't rode mine much since the adjustments, but just testing it out in the parking lot, it seemed fine, and even like it might have slightly more power and crisper too! (if you can imagine that)

Hope this works for you, and yes I believe that you are correct in assuming it isn't weather related. I've had it happen 2 times, each at extreme opposites in temperature.

 

I'll swap you my 12 year old Warrior for it, I've never had that problem. hehehe. lol.

No I realy like the Raptor but I think I'll wait a year or so more until the first run bugs are worked out of it. Lets all go riding!

 

It seems that a lot of the 4 stroke ATV's are comming in very lean...A byproduct of a lean condition is backfiring. This summer I purchased a 400EX for my wife. It was a tough starter, and would not run well til warmed up. I went to DynaJet, and purchased a jet kit. This helped, a lot. Once installed the I could start the quad with out choke, it ran smooth, great throttle response and more power throughout. I have a raptor on order and I have already talked with them and they are working on the problem, and plan to release a kit soon.

 

Gary,

I had the same problem, and the dealer told me and did the same thing bash said his did and so far no more problems. When jet kits are available it will be even better

good luck
mike 01 blk/wht raptor

 

I had the same problem w/ a Wolverine.Mine got better when I jetted it, but would still happen if I was a little too early getting off the choke.
I ended up grinding a little off that spacer that keeps you from tightening the clamp too far,this gave it a little extra squeeze on the spout.I sneezed it a couple of times since, no problem so far. Not sure yours has the same clamp,but I hope this helps.

 

Well my problem on my DS has been the valves, check then out. Mine did not have enough clearance. watch your rubber boots too/

 

Have you had the valves adjusted,when I did mine the valves were not even close. The intake valves were realy tight, maybe the valves are not closing properly. My raptor seemed to run better after doing this, and I have not lost the carbs. good luck.