Hello am new to the forum.Just bought an 04 raptor 2 weeks ago. Got the dmc alien full exhaust and K&N pro flow with pre filter and dynojet stage 2.everything installed 146/148's full throttle plug check says lean. 148/150's full throttle plug check says lean. after reading all the posts on jetting it seems most do allright with146/148's with full exhaust and K&N. I ride at about 1500 to 2000 average elevation. the exhaust recommends drilling on airbox and 155/160 mains.I have done no drilling and tried adjusting needles to 5th to no avail. low rpm performance is good no surge no backfire but at full throttle it seems to accelerate and flatten out. any suggestions on what size jets to order??

 

anyone??

 

Are you sure that you are reading the plug correctly and at the right time (wide open throttle) because with that setup, it is suggested to run 146/148. Did you cut your flaps on the rubber intake? That sounds as if it it would be too much for 156/160 mains. Not sure if you know, but Dynojet has different size numbers than other makes, so make sure that the suggested size that came with the pipe is Dynojet recommended sizes.

 

flaps are cut .running down long straight at wot for 1/4 mile kill engine and coast to stop check plug.the ground strap on the plug shows a white tinge to it no black to be found.Im sure this is the correct way to check the plug

 

also the jets Im using are dynojets. The pipe recommends a 155/160 I assume in mikuni but did not come with jets.

 

Well, The 155/160 jets that it recommends cannot be right. That it too much of a difference in the two jet sizes. Usually they are 2 numbers difference, like 146/148 or 158/160 for that matter. PM sixsixt, he is good with jets and maybe he can help. I don't want to tell you the wrong thing and he will have the best answer for you.

 

Mikuni jets are 5 spaces apart. You can get them in 2.5's i believe..I am running no lid on my box, K&N, below 3000ft, aftermarket slip-on, and 146-148 is fine for me...What about your air-fuel screws?

 

Go to this website. I learned a lot from this about setting up carbs. Maybe it will help because you are running at different elevation, different exhaust and the lid off(mine is on for mud). Let me know if it helps. It walks you through setting up each phase and jet step by step.




Jets

 

Thanks for the help guys. I already figured it out .If your curious how look at my other thread "problem solved". after talking with dynojet on the phone I get the feeling the people answering dont have any hands on experience it seems like they have a sheet of paper with answers to basic questions when I started talking about the numbers I was getting for co and hc on the 5gas analyzer they couldnt tell me what the numbers meant whether it was rich or lean so I tuned it like I would on a muscle car and it made the world of difference. I know cars and bikes are different but both are internal combustion engines.patience was the key.thanks again.