Alright any help that any one can give me is appreciated. I got a 2002 Raptor 660R, this thing has been a big pain in the ***. First the carbs were flooding and it would die at idle. So i had the bright ideo of jetting it hoping that this would solve my problems. Okay when i got the dyno jet jetkit it didn't come with the main jets for stock filter and exhaust which is what i have. So i got the bright idea of putting the just for the aftermarket pipe and filter. I took out the air filter and drilled lip 8 holes in the exhaust, trying to increase the flow. Anyway this is how it runs, it will only idle with the choke all the way out and even then it some what sputters and backfires. Right when i press the gas it wants to die. I heard something about the parking brake thing, might this solve some of my problem. If that helps it run, then what would help it not sputter. Thanks again, i'm about to torch this thing

 

I hope thats a typo' 8 holes in the exhaust' I hope you ment airbox lid. Sounds like you are running way lean. What kind of pipe do you have. Whats your elevation where you live. A little more info and I may be able to help

 

<div class="FTQUOTE"><begin quote>Originally posted by: Fulltiltrider

I hope thats a typo' 8 holes in the exhaust' I hope you ment airbox lid. Sounds like you are running way lean. What kind of pipe do you have. Whats your elevation where you live. A little more info and I may be able to help</end quote></div>

Nope it wasn't a typo, i figured slip on flowed a little better than the stock exhaust so if i drilled a couple holes in it, it would give me the same effect. The holes i drilled were in the back of the pipe. I'll take pics if you need them. I live in houston so i don't think the elevation is much higher than see level. Oh yeah and when its idling with the choke on it's back firing through the intake side, like the air box keeps jumping around. Thanks for you help, and if you need anymore info let me know thanks

 

If all this started after you put the jets in I'd take the carbs off again and look everything over. Make sure you're carbs seated up in the boots well and its not sucking air.

 

Koopa makes a good point. The rappys are known for blowing the carb boots off after a backfire. Most of the times this is caused by trying to start your machine with throttle. Alot of people turn down the idle on a rappy thinking its too high from the factory, then you have to give it gas to start it. This also is the cause for the one-way bearing problems. As for the holes, If you put them in the back of the pipe its not doing you any good. Pull out your spark arrestor and look inside. You will see a baffle with a small hole in it. Take a pipe and small enough to fit in the spark arrestor hole and pound out that baffle. that will make a difference

 

Man i know this is an old tread, but I'm having the same problem.
Did ya ever fix the real problem or even figure out what it was?
Thanks.

 

I would recommend getting the appropriate carb rebuild kit and start there. Tear the carb apart and clean every little passage with carb cleaner. Check for boot cracks and make sure your filter is clean.

This is a good baseline to start with. If you are getting fuel to the carb and it's components are in good shape, you can go from there. Maybe electrical or an air would be my next step.

Also, if a carb has been tweaked, make sure the jets are correct and in their right spot and clean. If all else fails, maybe time to check/adjust valves.

 

Well i removed the carbs to re-build and found the idle mixture screw tip was broke off in the seat on the left carb.
don't know if the rebuild kit comes with new seat or if i could even get it remove the old one. found a set on e-bay and there on there way.
Thanks

 

I agree with doing a complete cleaning.... Sounds to me like you either have a gummed carb or your adjustments are way off. The sucking air is a good possibility too. tell me this. Do you regularly run the carbs out of fuel when shutting down for an extended period of time? With the quality of the fuel and the corn alcohol that you have in it, gummed carbs are a big problem. Also, replace the fuel filters and make sure your petcock is not plugged.

I'd still tear into the carb one more time. I don't know your skill level mechanicaly, but it is a good place to start AND you will be fixing the boot issue at the same time.