XR250 setup/jetting question. Need Help!

I am a regular over at the DRZ site but I hope you don't hold that against me. A co-worker of mine bought a brand new XR250 to trailride with his son(XR70 so you get the idea of the intensity of riding). He bought the XR because of its ease of use, lack of maintainence required, and most of all the quiet. Since I am the "bike guy" at work he came to me with the following problem.


XR250 bone stock

5000' elevation.


Runs good at low RPM, good throttle response.

Hesitates at mid to wide open throttle, feels boggy.

1st cure attempt: Takes bike back to dealer where they remove the silencer baffle (restrictor). Bike now runs good except that it is loud, and has a mangled exhaust.

Is there a way to get this bike running good with the stock exhaust setup? (ie quiet). My first thought was the bike was rich wrt to needle position and/or the main with the restictor in place. He complained that the bike didn't have enough to loft the front with the restrictive exhaust in place. I responded by saying he should have got the 400. He didn't smile. He is my boss. Please help a hapless Suzuki rider.


I have a 2000 250 withthe following mods:

Removed intake snorkle

K&N air filter

FMF Powercore pipe

140 Main

48 Slow jet

12 tooth countershaft sprocket.

The bike runs great 2000 to 6500 feet. I have had several people ride it and they all have very positive comments about the carburation. I can lift the front in third gear with these modifications.

A better gearing selection would be stock countershaft (13) with a 52 rear but I am too cheap. I will do that when the stock chain and sprocket wear out.

I also ride with my wife xr70 and my kids xr50s and this combination is also a bit loud. I am going to replace the standard FMF spark arrester with the quiet core.

I have the same issue when I have my spark arrestor in, I regularly ride with it out because I get twice the power with no flatspot. Yes it is very loud. You could probably go for a FMF silenced pipe of some sort. Hopefully that would work. I am in Raliegh, NC not sure of my elevation, pretty sure it isn't much.

RKW, where did you find your air filter??? I can't find a K&N filter anywhere for my bike.


When they removed the baffle, did they remove the whole tip, or remove the restrictor and then reinstall the tip?. There is a big difference in sound between these two setups and not much difference in power. If the noise level is still too high with the tip in and the baffle out, the only alternative is going with one of the aftermarket "quiet core" exhuasts - he can expect to drop 300 to 600 bucks.

5,000 feet is pretty high (1 mile). I would think that the jetting might have to be adjusted for the altitude, although I am by no means an expert, and I'm just guessing. BTW, Danny - the Raleigh area is about 300' ASL.

Other mods that can be done (and should be done with a less restrictive exhuast) are removing the airbox snorkle, and the "backfire screen". This is inside the air filter and care should be taken to only cut/remove through the first layer of sreen to remove the "brillo pad" material that's sandwiched between the two screens. He should have the last layer of sreen remaining to provide rigiidity and protection for the filter.

There are MANY other mods for XR250, including pumper type race carbs, cams, headers, etc. many of them available from "XR's only". They also will perform a complete makeover to a 284(??) cc bike including many beefed up engine components to handle the larger displacement. Only thing is that it adds up to many $$.

Also, depending on the severity of the mid/high bog, it's possible that something else is wrong like a clogged fuel line or jet (common to occur only at mid/high revs).

Good luck,


Honda XR250,

I get all my stuff from Doug Johnson at Motocarrera (818)761-9040. He is a true friend and motorcycle enthusiast who was paralyzed in a Judo accident ten years ago. He specializes in 2-strokes like RD350s and 400 but has branched out. Tell him Rich Wheeler referred you and he will take care of you. He does a lot of mail order so if you are not local he can still get you the parts you need.

Also, I once called the K&N company and told them what I needed. They were very helpful and gave me a part number for a filter for my KX500. On the XR, I just called doug and he was able to look it up and order it along with a few other goodies.

Good Luck

Thanks, I'll go ahead and give Doug a call and get the air filter.

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