Question, and it's a question that's been asked, but I have yet to solve it. My best friend has a 01 Raptor. He is running a T-4 Slip-On with the K&N Filter and a little shaving on the airbox lid. He bumped the jetting up one to 145/150. He didn't move the needle. I know someone is going to say "Buy this or that jet kit". We just can't see spending $50+ on a kit, when all he should have to do is change the jetting and move the needle. We are at 651ft elevation. Anyone have any ideas on jetting setup/needle position?
The bike literally has not mid to top end. I think he still has bottom, but that might be because of the 13 tooth front sprocket. Thanks all very much.

 

Keep going up on the main jet until it stumbles then come back one. I've been told by some people that the top end won't increase without the headpipe, but I have beat many full exhaust raptors and have been beat by a few at Ols. Its all in the tuning. A quick way to see if you are too lean without rejetting is to cover up the hole on the airbox lid and then maybe part of the snorkle after you covered up the hole in the lid. That condition should make the bike run rich. If it does run rich, then he is close. If it runs better or the same, I would move up on the main jets.

 

It's actually worse than without the slip-on. That is what's so concerning. Thanks for the idea!

 

Instead of covering up the air box, couldn't he just drive the bike with the Choke on?

If it runs better, you are too lean on the main jet.

If it runs worse, you are jetted correctly????

Rob

 

Never thought of that way good idea.

 

I like my idea better! Just kidding. That may work too!

 

Tell him too leave the needles in the stock position....thats the only place I could get mine too run perfect when I ran the stockers.

 

Mine is Pro Circuit slip on only...Pro Flow Filter kit.....Dyno Jet kit.....146/148......Lid off (now).....Airscrew 3 turns out.....Dyno Jet Needles in 4th slot. I have experimented with different airlid mods opening 1 hole then 2 ,3, 4. With the afore mentioned jetting it is runnung well without the lid. I am gonna ride it a few days to see what the plug looks like. At this time I do not have any tell tale signs of being lean (backfire). I am at 1000 Ft of elevation. What does your plug look like?

James

 

UPDATE: Changed jetting to 150/155. Left the needles where they were. Went to Northern Wisconsin to do some trail riding yesterday. Ran much stronger, not quite what we are expecting yet. He still couldn't keep up with me, but it was a lot closer, maybe half the distance. Going to change the jetting to 155/160 and bump up the needles 1 notch and see how that goes, as soon as it gets back from the shop!! The bike just shut down and wouldn't start again. Looking around, there was oil all over the skid plate. We put it on it's tail and removed the skid, couldn't find where the oil was coming from. The we noticed that it may be coming from the output shaft, maybe the seal blew out? Is there a safety feature that if the oil gets low it shuts it down? I noticed two wires on the bottom of the motor, I think one would the the netural indicator, the other maybe a safety for the oil? The oil tank was dry, but there was still oil in the engine. It was running fine when it shut down.

 

Ouch, no there is no oil protecting curcuit. Sounds like he ran it dry and siezed. When he gets the motor rebuilt try 155/160 jets, put the needles back on the stock position, which is needles on 3rd middle groove and remove the air box lid. When jetting, its best to do one thing at a time so you can judge what change did what.