Rebuild season is coming!

Whaddup everyone,

 

Im taking my 04 YZ250f through her first winter (with me). Bought the bike 2 months ago and only had a few issues with it.

 

Thanks to many people here I am currently re-jetting my carb, and doing the oring mod to rid a bog.

 

My question is, since its such an old bike is there certain things I should replace/check condition of? Or is it only when theres a problem u replace things

 

The only issues i have with the problem is the clutch is very burnt, bogging when whacking the throttle (working on rejetting and oring), and recently also it seems to sound like shes screaming but i feel like im not going as fast, as far on the throttle (if that makes sense)

 

So for the winter season I was planning on some replacements/changes.

 

What i had in mind: forks (their leaking, going to take to a shop)

Chain: my brother suggested I change it

Top end rebuild: since i dont know when it was last done

Clutch: doing this for sure

Brakes?: my rear brake squeels sometimes when braking

 

My question, is there anything I should be specifically replacing for unknown hours/repairs this winter

 

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Obviously check valve clearance, but also check center intake shim size. The center valve usually wears the fastest. All intake valves should close to same size.
Grease linkage swingarm, steering stem bearings.
Sprockets look toast.
Where do you live the artic? Its not winter yet.

Brake fluid change.

Run water and white vinegar through radiator to clean cooling system.

Repack muffler.

 

 

 

Replace clutch plates. Sounds like clutch is slipping.

 

 

 

 

Rebuild in winter? Winter is prime time for riding, well here in the AZ desert. I put new aquatic mamels (seals) in the forks (2003 wr250f) myself! It is not a hard job, I found a video online ( you boob, I think ) and just followed the video. It's one of those "if I can do it any body that can change a tire can do it." Heck you already got her necked so just do the forks. Oh after you get everything done come on down to the desert for an off road test.

Obviously check valve clearance, but also check center intake shim size. The center valve usually wears the fastest. All intake valves should close to same size.
Grease linkage swingarm, steering stem bearings.
Sprockets look toast.
Where do you live the artic? Its not winter yet.


Thanks for the info, will look into all of that.

For the sprocket should i get stock sizes if im doing trail riding/hill climbs? Im not sure if ill ever actually hit an mx track. Maybe once or twice.

I live in North of Toronto, Ontario ( canada). Had first snow fall 2 days ago, only lasted about 1hr but it was snowing!

Brake fluid change.
Run water and white vinegar through radiator to clean cooling system.
Repack muffler.
 

Cool thanks, and will look into that vinegar water trick

 
Replace clutch plates. Sounds like clutch is slipping.
 

I was planning on replacing entire clutch, i was looking at a garnett dirt digger kit or oem.


Rebuild in winter? Winter is prime time for riding, well here in the AZ desert. I put new aquatic mamels (seals) in the forks (2003 wr250f) myself! It is not a hard job, I found a video online ( you boob, I think ) and just followed the video. It's one of those "if I can do it any body that can change a tire can do it." Heck you already got her necked so just do the forks. Oh after you get everything done come on down to the desert for an off road test.



Im in ontario canada we had first snowfall 2 days ago, and man id love to go for a desert rip seems crazy but nuthing near me

I like 13/51 sprockets for trail riding. You would need two more chain links to fit.

I live in Minnesota. I ride with snow on the ground until the ground freezes.

 

 

You have to be careful you don't sink too much money into a 14 year old bike.  It's very expensive to rebuild a 4 stroke.

I'd fix the clutch and new chain and sprockets and then see what happens.

I'd check the valves and if they are out of spec it usually means the motor is tired.

I rebuilt my son's 2007 WR250F and found a lot of OEM Yamaha motor parts cheap on eBay.  

Even then I spent more than I should have.

 

I have carb and engine rebuild videos for your bike:

 

Clutch video:

 

 

Make sure the cam chain is in spec, and the valve clearances. Cheap and relatively easy to do. Otherwise leave the motor alone.

Change out the clutch plates, I wouldn't bother with the "kit" unless the basket is tired. 

Definitely do the forks yourself. It's not rocket science, and if you're doing it as a winter project, there's no time line, and lots of bored guys on line to help out!

Mike (with a 2001 WR250F in Ottawa)

Stud that bad boy up and ride all winter.

Got a ride already studded. It's at the end of my sig....

2 hours ago, ckny said:

Stud that bad boy up and ride all winter.

You talkin about that fat pig Apex? A bus with studs handles better than that lol.

Stud up your bike dude. 

As for your bog set the air screw to 15/8 turns and adjust your ascelator pump the pump is set wrong put a 008 welding wire under the slide and adjust the pump so the pump comes on just after idle motor can't take a lot of gas as for your jetting if you put a pipe on it go up on the pilot main should be good

7 hours ago, ckny said:

You talkin about that fat pig Apex? A bus with studs handles better than that lol.

Stud up your bike dude. 

I could stud my bikes, and have them sit in the garage. 400+km days at speeds up to 160k scratch all of my itches during the winter.

I bought a Renegade last season and never mounted my studs on my bike. I was on my sled 3 days a week at times. More boondocking than fast groomers. 

Upgraded to my wr450f now but i enjoyed cleaning my 03 wr250 up with decals. Home made bash plate. What a beautiful bike to ride... Jetted and yz muffler. It was an absolute blast to ride!

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Recently Ive been thinking. If i could sell my 04 yz250f for a couple hundred more than i got it for and all i put into it was $61 for jetting. Im going to a 2stroke, probably a newer model ('12+) ktm

 

 

Your only weak point in that motor is your timing chain. And, if that goes, so does your motor. So, like the other person said, check your valves. If they are in spec, and the bike does not smoke and starts and idles well, then maybe you can get away with just replacing the timing chain. But, if you are that deep into the motor, a few more bolts and you can easily replace the piston and rings. That is a good bike and worth the investment in my opinion.

My '06 WR250F bogs off idle if it is sitting and I whack the throttle open but it never bogs on the trail. No 4-stroke will come off idle like a 2-stroke. Is that what you are comparing it to?

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