2001 Xr250

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#1
Ok, I am Strongly considering getting a 4stroke, My mind is made up on the XR250, what do I need to do to it when I get it, and is there any problems with it? Such as gearing, reasonable amount of power stock ? etc.
 
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#2
At the minimum,Get a Summers Racing Fork Brace($199) because your front forks flex too much and are harsh over the bumps Set you sag on the rear. ($0) Get an aftermarket airfilter(NoToil,Uni orTwin Air,$20). Take the snorkel out from under the seat so your bike can breath better,$0. You just pry it out .Buy a Thumper Racing exhaust insert($79).Go up two on the pilot and main jets.($7)Change you oil as often as possible(every race or 100-200 trail miles)So for about $300 it becomes a fun trail bike.

As your skill increases, or you want to do some enduros or cross country,look into aftermarket pipes by Big Gun,XR's Only,or FMF($229-300) Look at suspension work(Scotts,MX Tech,Thumper,Race Tech,Precision Concepts)To do front and back suspension you are looking at about $500.(the suspension work I believe is your biggest bang for the buck and the most ignored part of upgrading a bike)A big bore kit of 280cc,300 or 320cc can be done with a Mikuni 34mm carb. A stainless steel oil filter(Scotts or Thumper $ 65),Steering stableizer(300-500$),handlebars (Tag,Renthal,Moose $ 77-100)Better tires(Dunlops 756's,755's.Michlin S12's,These last few modifications will get the little XR off the porch and be competitive with the big boys !



:cool: :cool: :cool:
 
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#3
jsmith: xrsforever has given you some good advice there. Jetting can vary somewhat due to altitude though. I don't know how they are geared over there, but here in Australia they are way too tall.
 
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#4
I already have the biggest jetting headache in the business, the CR250 2001. If I have to rejet a XR250, I may not get one. I have done some racing on my CR, now I'm just looking to do some Long trail rides with a friend who is also getting a XR250. Surely the jetting is OK stock. 4 strokes don't fowl plugs, do they?
 

CRGuy

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#5
I think they can foul plug's. Only with fuel and carbon though. Good luck and happ trail riding.
CRG
 

JuliusPleaser

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#6
Definitely do the airbox mod first. My XR250 came without a baffle, and it was loud, but not YZ loud. The airbox mod made a noticeable improvement. I never touched the jetting.

Since you live in the Southeast, the next thing you should do is install a set of Dunlop 752s or Michelin S-12s. I would tackle gearing at the same time. Like John K said, XRs are geared WAAY too high from the factory. Try going up one tooth on the C/S sprocket, or up three or four on the rear.

These mods alone make the XR a great little trail bike. I left the suspension alone on mine. I like my woods bikes soft--like my women.:)
 
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#7
Definitely do the Thumper Racing muffler insert -- for a stock displacement XR, it's as much hp increase as a complete aftermarket exhaust.

I personally like the plush suspension of the stock XR250, it fits the power delivery, and it really is tuneable, which the older XR's definitely WEREN'T!

The Summers racing fork brace is a must if you do lots of whoops and fast open stuff - for tight trails I don't notice the difference as much (just my opinion).

I ride anywhere from 600' to 8,000' and did not have to re-jet with the Thumper Racing insert and the snorkle removed. The stock filter on the newer XR's actually flows well, and you might want to keep it.

As far as jetting goes, yes, four strokes can foul plugs - but only if the jetting is too rich (just like two strokes). With an increase in airflow (airbox mod and muffler mod) more fuel may be required, or you will overheat/lean seize the beast (just like a two stroke). This is just basic maintenance stuff which you would have to do with ANY bike you purchase.

That said, on most of the 2001 XR250's I have come in contact with, the stock jetting is okay after the mod's we've mentioned. I have seen two XR250's which required larger pilot jets. Both of these were running right at sea level in humid conditions.

These are cool, fun trail bikes. Keep in mind that Dirt Bike (or was it Dirt Rider?) shootout a few months ago rated the XR250 over the WR250 for best trail machine :)
 

TexKDX

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#8
The stock XR will benefit from the basic breathing mods, all $0 efforts, and can be run with the stock jetting around sea level up to 5k feet no problem. The $0 mods are:

- pull the snorkel out with a pair of pliers from under the seat
- cut the screen out of the stock air filter basket with a utility knife
- pull the stock baffle out of the muffler - Dirt bike spot welded a steel rod in then beat it out with a hammer
- pull the head pipe off and grind the head flange welds down with a dremel or carbide cutter in a hand drill

Unless you buy a closed-course MX bike or a KTM, you can't get away from these types of mods. Even the WR426/250 needs these types of mods.

The stock carb on the little XR is easy to get to for jetting changes, unlike the carb on the yamaha 250 and 426.

Gary Hazel at Thumper sells the 34mm pumper carb but says it is of marginal use with the stock cam. Cam changes on the XR create their own problems and are usually judged as not needed if you want a good reliable bike. It might make sense to have te 34mm on a stroker/big bore/hot cam/ported head bike, but for anything less than that throttle response will suffer with the larger carb bore over a rejetted stocker.

With just the free mods listed above, my '99 has excellent throttle response and mid-range power. It is also hard to stall and has great lugability. A friend rode it yesterday and had recently rode a 400. He disliked the 400's ergos, weight, and height, but liked the little 250.

I've got just 20 miles on mine in the sloppiest conditions I've ridden in years. The bike flat handles, has great ergos and brakes, and puts the power to the ground. I am gonna like this bike. It will do everything my street legal wr400 did but with comfort and less weight, except for the big rush of power on top I rarely used.
 

Rodzilla

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#9
If you're looking at the Thumper insert, also look at the "Vortip" it's about the same price as the thumper unit, if I remember correctly the Thumper unit needs to be repaccked periodically. The Vortip does not use packing to dampen sound, just unequal length tubes. Baja designs sells them

Goes on in about two minutes, I love mine on my XR400

I'm taking a different tack from Tex on the filter screen though, I'm of the mind to leave it in as is Scott Summers, he says removing it is not needed and that it changes the airflow in a negative way. just my opinion.

Rod
 
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NVR FNSH

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#10
Four strokes don't foul plugs? Just ask someone with a YZ/WR400.....

My '99 WR400 has never fouled a plug but I also had to spend some time getting the jetting right so I could start it in my driveway. My wife's '92 XR250R is the world's greatest trialbike - might have to buy her a new one and keep the '92 as a 3rd bike.

Brian
 

TexKDX

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#11
Originally posted by Rodzilla
I'm taking a different tack from Tex on the filter screen though, I'm of the mind to leave it in as is Scott Summers, he says removing it is not needed and that it changes the airflow in a negative way. just my opinion.

Rod
Yea, there are multiple approaches on the subject. BTW, the TwinAir filter for the XR250 comes with its own basket and has no screen...

I've been told that on the 600 removing the screen hurts low end throttle response and to leave it in those.
 
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#12
Before you mod anything, just ride it and get used to it.

If you want to mod it later, do the mods which address the areas
you feel need attention. Otherwise, you run the risk of goofing
up a bike which may already be perfect for you.

Also, make your changes one at a time, so you know what effect each
has. Too many changes at once, and you may find yourself with problems
and have trouble figuring out which mod created them.

XRs are fine bikes, right off the showroom floor. You won't beat YZ426's
or CR250s in drag races, but you can have a blast on them just as they are.

HammerXR
 
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#13
First change the tires to a decent intermediate or soft terrain tire. Michelin s-12's are very good. Then ride the bike and see what you think of it. If there's something you don't like then consider changing it. You might even like the stock tires.
 

TexKDX

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#14
Hammer, I respect your opinion but don't share it.

First, I never just go ride a bike when I get it, new or otherwise. It gets a weeks worth of evenings going over it. Lots of threads have been written here on the problems many bikes have from the dealer prep process. Not to mention righting the wrongs caused by a previous owner on a used bike.

Second, when a bike come purposely restricted from the manufacturer it does not perform up to its ridability potential. Even if you are not after every last fraction of horsepower available (which an adult on an XR250 probably needs), the bike's throttle response will be below its potential.

Did you know the XR250's rear shock comes with the compression set at full hard? And the forks one click from full hard? Both need to be backed off 5 clicks before the bike is ridden unless you like bouncing off rocks and roots.

JMO,
 
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#15
Ditto with Tex's opinion.It is always a good ideal to go over every bike new or used before riding it. Also learning to work on and improve ones bike can be enjoyable.:cool: