Several of the guys have said that their Raptor seems to run better after they removed a section of rubber inside the airbox snorkel that restricted airflow. I removed mine, but it has had the opposite effect.

It has stock jetting and I'm at 400 ft. Prior to my monkeying with it, it was super crisp and pulled hard as soon as you entered the next gear.
Now, when doing a full throttle run (letting off between shifts), it hesitates just a moment when it is shifted into the next gear. I was cautious to blame it on the now, unrestricted airboot, so I put some tape over it to simulate the restriction. It seems to have most of the crispness back now. What should I do other than leave the tape on there? Does this sound like a lean condition, and if so, how much of a jet size increase would you start out at? I think the carbs are at 140 and 145 now.

Thanks a ton in advance,

 

Probably just one size up. I would probably get a 150 and put it in the 145 carb, and then put the 145 in the 140 carb. Test it out, and do a plug check. Being close to sea level, you might need to go up two sizes.

 

I just got back in. I put about a 2" piece of duct tape exactly were the original restriction was, and it rides just as good as ever, so that is definitely the problem.

Do you think that going up on the main jets will bring back the crispness, or will I have to fool with the intermediates as well?

Got any idea what kind of jets it takes and where to get them before I tear into it? I'd hate to wait with it just sitting there apart waiting for jets to come in.

Thanks again!

oh, one more thing. If it is pulling enough air to lean it out, is it reasonable to suspect that with an increase in jets to get the fuel/air mixture correct, it should have more power than in the stock configuration?

 

Correct jetting should make it better than before you took the restrictions out.

I believe they are standard mikuni small jets. Any motorcycle shop should have them. These arn't particular to the raptor, or yamaha.

I'd take one out just to make sure you get the right kind and don't have to make another trip to the shop. I'd probably get a couple of sizes larger since they should be but a couple of bucks each.