I know that there are a lot of jetting topics, but I can't seem to find one that match's my problem. And look at it this way, you get to post more and show how smart you are.

Alright, here is the problem. I have a 2002 yamaha raptor. I just recently bought a full yoshimura comp exhaust and dynojet jet kit. I already have a stock size K&N air filter installed. I jetted the raptor with 146 in the left carb and 148 in the right carb. I put the clip on the fourth groove from the top of the needle. I turned the fuel mixture screws in all the way and then turned them out 3 full turns. I cut the little tabs off the snorkel and cut two 1 and 3/4" holes in my air box lid. My elevation is below 3000 feet. I tried running it and it does good until about mid throttle. It is then that it sputters. It is almost like running it with a rev limiter or something. We tried adjusting the fuel mixture screws and it seemed to get a little better but still didn't go away. We even turned the fuel mixture screws all the way in and it still sputtered. Please help me if you can. I would appreciate any input. Thank you.

 

We got a 03 with DMC exhaust on, that does the same thing. I think our floats are off. Could be the same.

Also is this in about 1-2 gears. Are you sure your boots are not leaking air in after the carbs. Can check by running the engine and spraying carb cleaner on the boot and see if the idle changes. I have had this happen.

 

We did try to adjust the floats while i was jetting it, but i don't think we adjusted that much. I will try the carb clean tomorrow. and, yes it is in 1-2 gears. the raptor also sputters whenever i try to ride a wheelie. people suggested adjusting the float, and that is why i adjusted it when i jetted it. but it still dies in wheelies.

 

I'll fix this...


THROW AWAY THE AIR BOX LID!!! DONE!!!!


or even better just clip down the front clips(to hold the a/f in place)place the remaining 4 clips under the lid creating an opening....mine did the EXACT same thing...I bought an extra lid $10 and cut it all the way out leaving just enough to hold the a/f properly

Jason

 

What jay said would be easy to try. Also try putting the needle on the 3rd groove.
AND
The best thing to do is check it before you take it apart, with a piece of clear tubing. You can get the tubing at a hardware store for 20 cents, 1/8" clear tubing.

Thu September 05, 2002 3:11 AM



The quick & easy way to check float levels is to use a clear tube that fits the dump hole on the bottom of the carbs. You'll need at least one foot of tubing. Don't worry about an exact fit, the tubing can be a little bigger which will cause some of the gas to leak out but gravity is forgiving and is constant! You can get the tubing from your Yamaha dealer for a few bucks. Remove the stock dump hole tubing, put the new tubing on there & then bend up the other end and run it along side of the carb with the open end facing up. Then open the drain screw next to where the tube is connected & the level of gas in the tube should fill up & be level with or slightly above the bottom/top half of the carb's mating surface. If not, you'll need to adjust the float levels. A sign that the float levels are too high is if the stock drain tubes leak gas while your riding, you'll smell it for sure.
I just pop the carbs on the boots and set the tank on the frame and hook up the hose to check it again, you may have to take it back off once or twice to get it perfect. I also measure the amount that it is off and then take it apart, measure the float height and then bend the tab enough to raise or lower the float the amount that it was off. If that makes any sense.

 

i heard about that float solution before, and i think i am going to try that this weekend. when i was reving the engine i saw some gas coming out of the bottom tube. so, maybe my floats are off. as for the clips, i would have to change both of them right? i guess i will check the floats and then go from there. so, i am definitely running to rich, right? thanks for all the replies. that is why i love this forum. later.

 

Yeah it sounds rich, and yes you adjust the needles the same on both carbs.
Adjust the floats first they will effect everything else and you shouldn't be getting gas out of the over flow sitting still, but riding you will usually see that it has spit some out.

 

thanks a million for the replies. when i check the floats, do the carbs still have to be on the bike or should i take them off? I know the carbs have to be level so what should i do? thanks again.

 

You can do it with them mounted, takes about 2 minutes to check.

 

I have the exact same set up as you and same elevation. In my sig you will find how I jetted my bike. I even have the wholes in the airbox and I am still running my lid. Here is what we had to go with after a couple of try's. read sig!