2000 YZ250 Wide Ratio Option

[Sphinx]

I have a 2000 YZ250 2-stroke and was curious if anybody knows, if the wide ratio gears, from the Yamaha WR series, would fit my bike? I believe I read somewhere the four stroke YZ400F/426F/450F uses the YZ250 2-stroke transmission, and the WR is basically the same bike. Thanks in advance.

 

[dtsviper]

Well, I don't have any personal information for you. Just thought I would bump you so maybe someone will take notice! :p

I am still waiting for some good information on my request for information on the KX250 WR Option...

Later and good luck! :cool:

 

[Humai]

It would warrant investigation, because the YZ two-strokes and 4xx four strokes share gear ratios in many cases and we know that YZ 4xx to WR4xx gear conversions can be done.

For the good of mankind, let us know!

 

[Sphinx]

I found this link. Seems like it should be possible. If it is in the $300 range for parts I would consider it. http://www.thumpertalk.com/bike/ubb...Old=allposts&Main=22928&Search=true#Post22928

I will see if I can work up a parts list.

 

[Robcolo]

dtsviper----nowhere could I find a wide ratio set for my 98 KX so bought a KDX instead [a bad move]. My old 88 KX has the factory wide ratio 1st 2nd and 5th gear set and it's sweet. IMS and Moose both offered wide ratio sets for the CR but neither carry them now. Larry roeseler @ Stroker doesn't know of anything for the KX so we might be out of luck. You might try TUF Racing in DeKalb, Ill.

 

[dtsviper]

robcolo,

Well, I am moving from a KDX to the KX. I think the KDX is a fine bike, but I was wanting something with a little more. Boy, did the KX ever have a little more! LOL

Oh well, I guess I can always switch gearing on the final drive, depending on the race and conditions. May also look into the compatibility of the new gearing in the 2003 KX - in that bike the gearing is wider on the top end for fourth and fifth gear.

Thanks!

 

[olddirtbaginmt]

I've been running the wide ratio since purchasing my 99YZ, at the time we purchased the gear set from the WR400. I'm very happy with the set-up and feel it makes the bike much quickier in the woods - it just seems to pull longer and matchs up to the engine better. Now if I was a motocrosser, I may have liked the close ratio better but feel the wide ratio fits my manner of ridding much better.

 

[Sphinx]

I priced out the parts on www.partsfish.com and it is about $400 inlcuding almost all the bearing and clips etc. Which isn't too bad for a new transmission. It would be closer to $300 if you only get the gears, but it doens't make sense to me to split the cases and not put in new bearings. I would rather do it once and right, unless of course you have a new bike.

 

[stef]

we had our dealer do this mod on a 2001 and 2002 250'when we bought
the bikes. cost was around 350dollars for a complete box installed . they use
the original wr 400 components as apparently the 426 is slightly larger.

 

[tricci]

Stef,

since you have already had it done a few times maybe you could assist some of us and let us know what part numbers were replaced. I wouldn't mind doing it myself but I want to ensure I buy the correct parts.

I Know this may mean you'll have to dig up an invoice but it would be greatley appreciated by several on this board.

thanks in advance.

 

[stef]

Unfortunately dealer will not divulge the part numbers as he
sells a lot of these modifications , he only mentioned that it
is based on the wr 400. My guess is that he replaces all shafts
and gears, as you recieve your complete yz cr gearbox in a
bag if you want to change back at some stage, sorry i can not
be of more help.

 

[olddirtbaginmt]

Ricci:

The following was sent to another fellow that asked about this modification; the one thing you will need to do when installing is to relieve the case where first gear meets it, as it is wider than stock; just use the new gear to mark the case and use a dremel to grind material about the thickness of your thumbnail to give it enough room.

The following are the part numbers and Yamaha's description:

5BF-17211-00-00 Gear, 1st wheel
5BF-17221-00-00 Gear, 2nd wheel
5BF-17231-00-00 Gear, 3rd wheel
5BF-17241-00-00 Gear, 4th wheel
5BF-17251-00-00 Gear, 5th wheel
5BF-17121-00-00 Gear, 2nd pinion
5BF-17131-00-00 Gear, 3rd pinion
5BF-17141-00-00 Gear, 4th pinion
5BF-17151-00-00 Gear, 5th pinion
5BF-17411-00-00 Axle, Main

Hope this helps!
Olddirtbag(Tom)

 

[dtsviper]

Man! That is awesome!

I wish I could find a dealer or ANYBODY that could clue me in to how I can do this to my 2000 KX-250. Maybe an early 90's KDX-250 tranny?

I have a seperate post similar to this one on the KX. Not as fortunate as you guys!

Good luck with the conversion! :thumb:

 

[tricci]

Thanks olddirtbaginmt,

Stef,

maybe you can give me an idea as to what is in the bag?
Is there just gears and if so how many of them? or Are there shafts as well and other various tranny parts?

I'm trying to fiqure out if just replacing the output shaft gears is enough or if your need to replace the input shaft gears as well. Also are there any shafts and other parts in there. Like shifter drums or shifter forks or any other strange tranny parts.

Thanks,

tricci

 

[stef]

Tricci,
The parts returned are:
-Main input shaft
-2nd to 5th drive (pinion) gears
-1st to 5th driven gears
Hope this helps

 

[tricci]

Thanks stef,

That's a great help. I'm sure there will be more than one of us here who will appreciate your efforts.

Maybe you could take a moment and give us a few of your words on your opinion of the wide ratio YZ 250 you now have? How it feels and the main difference in performance and rideablility?

Cheers,

tricci

 

[stef]

Tricci,
the riding that we do consists af bouncing/crawling up and
down loose rocky mountains in 1st to pinned in 4th and 5th
cowtrails. we definately need the versatilaty of the wide ratio
box. The only real options we have available in 2 stroke
bikes are ktm exc or modified yz's. The yz works great
with the wr box and doesnt bog between gears (even in deep
sand). This bike can lug down to walking speed with out stalling
(wih add on fly wheel weight)and 5th makes yours eyes water.
If you dont need the top speed , but still want a granny low,it
might be worth while investigating changing 1st, or 1st and 2nd
only. We used to do this to rm's by fitting pe first gears.
good luck!