New 02 WR250F

Just wanted to thank everyone for the wealth of info I found on this site. You see I recently bought a low hours stock WR250 from an estate and after servicing it and cleaning the carb I could only say "Nice suspension and handling but really slow and hard to start". Removed the airbox lid and muffler insert and raised the needle one position and changed the main to a 178. Better but still kinda slow and hard to start. After reading about the exhaust cam being advanced so that it dumps the power stroke early to allow the exhaust time to get out of the small tip and the newer models having an autodecompressor in the cam to aid starting, I purchased a hot cams stage 1. Boy that was the ticket. Compared to stock this thing, well it doesn't compare it is so much faster now. Kicking it is a breeze and I don't even fiddle around with finding TDC anymore. Just casually kick it a couple of times and it starts. What a fun little bike. Thanks to all who suffered figuring all this info out years ago. Made my life easy today.


Awesome. :)

I recently (last July) bought a garage queen 2002 WR-250F, myself.

Literally, the bike looked as if it were ridden one month and then parked in a sealed container for 10 years.

I removed the airbox lid, replaced the exhaust header pipe and muffler with FMF Powerbomb and Q4 items, unplugged the infamous gray wire, and did a couple of basic jetting changes:

2002 YZ-250F needle and (if I recall) slightly smaller main jet (yes, smaller, due to the YZ needle), O-ringed the accelerator pump levers, and installed a smaller leak jet.

After these changes, the bike ran as I expected it to run, which is very good.

I am still amazed, at times out there in the woods, that it is "only" 250cc.

This is my second WR-250F, too (regretably sold my 2009 model after a bit over two years of riding it).

One thing I always seem to disagree on with my bke is that, for some reason, it is always easy to start.

I'm not complaining. :)

All I do is push the kickstarter down until compression pressure stops it dead, squeeze the decomp lever on the handlebar a tiny bit, allow the kickstarter to move down about 2 inches, release the decomp lever, bring the kickstart lever back to the top, and give it a normal kick.

I don't touch the throttle grip while kicking.

It always starts.

I now ride the bike practically every weekend.

Edited by YZEtc

Hey guys,

What a coincidence to find a thread about a 02' right now! I have a 02' that I've had since new, it's not been ridden much since it's first couple of years in life due to moving away from home and land usage problems in the UK. I live in NZ now and I'm having it shipped over in the next couple of months and I'm really looking forward to it.

I had been looking to buy a new bike but I'll save that until 2014 at which time I suspect I will keep the WR as a second bike.

I see the cam DanSh mentioned which is interesting and YZEtc I see your upgrades.

What else can I do to bring out more of the bikes potential?

How much more power is available from the bike and likewise what would you do with the suspension?

Thanks in advance guys!

I don't know whether or not UK bikes come in a restricted form as my bike did, but if yours did and you want it running as well as possible, you'll need to address that.

Suspension setup tailored to each individual rider is a biggie with any motorcycle that has a suspension.

In my experience, since there is no way Yamaha Motor Co. can produce the bike to exactly fit all riders alike, the most basic thing you can do is to determine whether or not the suspension springs are the correct ones for your weight and preferrence on how you like the bike to feel, and to achieve a good-feeling chassis balance.

In other words, not having the back end sitting too low or too high, and same with the front.

The difference between right and wrong in this area can be astounding.

Fine-tuning of the damping (revalving), fork oil levels, clicker settings, etc., are also basics.

Too, keeping the chassis bearings lubricated is something often neglected.

In fact, I say that once you are sure your bike is not restricted, performance-wise, I'd look into suspension setup.

Edited by YZEtc

I never saw any mention of the grey wire. I remember something about it from a dirt bike article years ago though. Where do I unplug it and what does it do?


Was looking specifically at cam and carb topics. Found the grey wire info under the free mods section. Time to take the seat and tank off again.


Dealer had unplugged the grey wire and cut the throttle stop. But, they had cut the throttle stop to .975 shank rather than .875 shank. Probably needed reading glasses like myself. Now all is well. thanks again.


Have you felt much of an improvement?

While cutting the throttle stop .1 inch I also added the o ring to the accelerator pump lever. Has a little better throttle response off idle and a bit more power up top now. Compared to how the dealer delivered it with only the grey wire mod and throttle stop partially cut, it runs night and day different now. Surprised to see the exhaust insert still installed at delivery, but it was sold new in California and that mod is so obvious to the world they may have been afraid to remove it. Compared to how it was when I bought it, the bike runs night and day better.


Hey guys,

My bike is probably a month away with the shipping but I can't wait!

I've read a lot on here now in the fantastic FAQ section. Who ever wrote that, well done and a sincere thank you!

I would love to replace the stock exhaust with a Ti one. The UK muffler is different from the US one but the aperture is still small so I suspect it's a similar story with holding back power.

What are my options?

I would love to reduce the weight of the bike an this seems a good place to start!

Next I think will be bars, pegs, brakes and lights. All seem to be areas where functionality can be improved and weight lost.

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