Poolplayer.....when introducing more air into the engine, the potential of having to rejet is always a possibility. You probably only need to richen the idle circuit(s). Turn the 2 adjustment screws (under carbs, on the cylinder side) out 1/2 turn...this should help. Practice your starts too....lol.

 

Hello, I am Poolplayers freind. My Bike runs like POO to. I have a K&N Fliter and iam getting a White Brothers Pipe tommorrow. What size jet kit do i need? (Stage 1,2, or 3) I am going with White Bros because my Brother has one and he can keep it Quiet. Noise is a concern in some of the areas we ride. Are White Brother Pipes any good compared to others? I had a DG pipe on a Warrior and it was way to loud. Thanks for any info.

 

I like all kinds of riding,especially drag racing other bikes.I do go into alot of tight trails around my house.I might wait till my friend(jumpinjack)puts the jets in his before I do.Do you think I should stay stock? Will jetting and piping be bad for slow trail riding?

 

[img]i/expressions/face-icon-small-smile.gif[/img]Lots of good suggestions here, especially after the actual problem is discovered. I am surprised that no one has suggested what may be the very first step; that is, doing a test ride and plug read. When all is said and done the plug from your very own engine is the final indicator of your air/fuel mix, regardless of air flow changes, elev., nunber & kinds of improvements,etc.
If you do not know the proper way to run a test ride/plug read, I have written a tutorial with a photo of a plug from a correctly jetted engine. You are welcome to e-mail me for it.

 

Airraptor,

Before you went to the 686 did you ever use the Dynojet kit? Just curious. I don't know about how a dynojet kit works with the 686 but I as well as many others can feel a very noticable increase in response from our machines over the stock needles and jets. The dynojet kit for me was a very good investment.

 

Yes, why not at least try the Dyno-Jet kit out? And why the stock muffler? Just curious.

 

I say get the jet kit. My personal experience is that you do need the needles. They are much richer than stock and they do work. I know airraptor doesn't believe it, but it sure made a heck of a difference on that mid-range stumble on my Raptor. Also, if you open up the air box lid, you may want to go to 25 pilot jets. Once again, airraptor will disagree, but from my personal experience, my Raptor needed it. Should have done it BEFORE it gave me a lean backfire on a hot restart that fried my air filter and slide in the right carb.

 

I think every bike runs a little different and where the dynonjets work with one bike the mikuni's may work better on another...even with the same mods.

 

airraptor, 1st, I wasn't calling you out or trying to be a jerk, I just know that we have gone around about this before and you have your beliefs and I have mine. My carb boots were fine, I never did pop mine off actually, even with the lean backfire that fried the slide and airfilter (it was an '02). My beliefs are based on the progression from stock to where it was when I sold it. 1st was bone stock until it was broken in, rode fine, but power was a little mild for my taste. 2nd was stock with snorkle flaps trimmed, ran like crap, very lean in the mid range. 3rd was DJ kit (142-144 mains)with Pro-Flow adapter w/ foam filter and air box lid drilled with about 10 1/2" holes and it ran much better, but was lean on the bottom end. 4th step added the FMF PC4SA slip-on, mains to 146-148, pilot screws to 4 turns out, and back half of lid cut open and it ran better, but was still lean down low. That is how it was when I fried the filter and slide. So then I added the 25 pilots at 3.5 turns, and it ran a lot better on the bottom end, but it was a touch rich. Finally, I turned the pilot screws back to 3 out and the bottom was just about perfect. As far as a stumble being rich or lean, you have to be careful on the terminology. The way I describe it is if its slow to respond kind of stumble (bogs) that is lean, but if you get popping in the exhaust kind of stumble that is rich. When you are dealing with the internet, that's the hardest thing with jetting. Is your stumble the same as my stumble? The best thing I did was buy a book about working on dirtbikes. I can't remember the name or the author, but the guy was a factory MX mechanic and the book has a 20-30 page chapter dealing just with carbs and getting the jetting figured out. It is very good. I bought the book at Barnes and Noble and it was about $25. I'll find out the specifics on it when I go home for lunch.

 

With these air filter,box mods. My questions comes into play. My 02 raptor has its prodesign filter kit with the KnN filter on order. When i install it All I am going to do is just put it in with no other airbox mods at this time. next spring I will update the pipe, and airbox, but intill then with just the replacement of the old stock airfilter with a KnN filter should i worry about the jets and needle placement