YZF426F front end on 1990 KDX 200?

[Terrence Sprocket]

Just wondering if anyone has done a fork conversion like this? I know of Alot of peps putting KX front ends on, but I'm just curious if the 02 YZF front end is possible. Would it require pressing the KDX stem into the YZF bottom clamp? Those yzf's have great front ends, I hope it can work....

Thanx.

PS: the KDX is a 1990 model with original standard forks.

[Julien D]

Pretty much any fork swap is possible. Yes, you would need to press the KDX stem into the lower YZF triple. Probably fabricate a bushing for the upper triple, and possibly some work to the steering stop. You would most likely need the complete front end, wheel and all.

[Terrence Sprocket]

Yea, I figured the stem would need to be swapped out. I did find a complete front end ( forks, triple clamp, front wheel with axle, brake assembly). just waiting to here back on the price. I was curious if anyone here did a similar swap b4. I wonder if the the stem diameter would be the same for the bottom clamp? I could alwas look at pressing new bearing races in the gooseneck if need-be.

[gsa102]

Here is what I found out from my DRZ fork swap using a YZ450F wheel:

The YZF wheel and forks use a larger diameter axle than the KDX. Not likely that a KDX wheel will work, unless you source wheel bearings and seals with a larger center, and a center spacer.

The KDX caliper mount will bolt right on. The DRZ, YZF, and KDX all use the same mount. You may need a different brake master cylinder to fit the fat bars that are standard on the YZF, unless you find spacers to mount a 7/8 bar on the triple clamps.

I didn't have YZF triples, so don't know about swapping the stem on those.

[Terrence Sprocket]

Ok, like I said, I'm getting a complete front end which included the wheel, axle, complete brake setup, triple clamps, etc. So I don't have to worry about using different wheel bearings and mixing and matching. It should be pretty good as long as I can change the steering stems smoothly.

[gsa102]

I recommend that you don't buy them and here is why:

I have the same forks on my 07 WR450F. I had them resprung and revalved and I am still not happy with the results. They deflect off of rocks and are harsh in the mid-stroke. WR450 owners swap to the 06+ YZF SSS forks for far better performance. I was contemplating the SSS forks or the DRZ units like I put on my KDX.

I may never trust those forks at speed again. Two summers ago they deflected off a rock and washed my front wheel out. The next thing I knew, I was on the ground with several broken ribs, broken collarbone, and collapsed lung. In doing research on solutions, I found that nobody has a "gold valve" cure that works. They are OK moto forks on a groomed track.

[factoryX]

The yz426 uses 46mm kyb's I believe.

[Terrence Sprocket]

I had an 02 wr250f with similar front end as the YZF model ( progressive springs). I found they worked great. That's why I would like to find some similar for my KDX.

[Terrence Sprocket]

I also found a 94 KLX 250 front end, with the inverted forks. It too is also complete with wheel, axle, etc. Would they be much better than my current 1990 KDX front end? I'm assuming they too would have progressive springs for trail riding, but they might be stiffer cause of the KLX 250 being a much heavier bike. What do u's think?

[Julien D]

Not really, no. They would be marginally better than your KDX forks, but not enough to make it worth the time and trouble unless the front end is practically free.

[Terrence Sprocket]

Yea, I suppose. So what would u recemend? I would love to find a modern KX 250 or 500 front end, but I can only find the forks and triple clamps. I'ld rather find one that's complete with front wheel and axle.
Actually, I wouldn't mind building a hybrid with a nice MX chassis. Having a hard time finding one that's resonably priced. I'm pretty good at cutting, welding, and fabricating, so that's not the issue.
I aslo have to send my cylinder for replating, Yikes! This is getting pricy. Just picked up a left sub-valve for my kips too. I had this bike forever and I think it's well worth the emptying of the wallet. I hope I can find a good front end or nice MX chassis. All those new bikes suspension is to die for!

[Terrence Sprocket]

The YZF front end is no go. The seller wants way too much for it. I can't say that I blame him, it's prob the only good parts left on his bike. Lol.

[Fletch]

Heard great things from several boards on the conventional rm 125/250 forks from the 96-98 bikes(I think the years are correct...) These may be the same as the drz forks, I just don't know. cheap forks to find though...

[Tedh98]

Heard great things from several boards on the conventional rm 125/250 forks from the 96-98 bikes(I think the years are correct...)

+1 I've read the same thing from multiple sources.

[factoryX]

49mm showa's, same forks on the drz with different valving.

[gsa102]

Factory X is right, the crappy 48mm Kayabas were used on the YZF 2004-2005, and are on the WR450 2005?-2011

I apologize for not doing enough research and leading you the wrong way. But I DO really like my DRZ forks. The DRZ units are supposed to have valving better suited to off-road with larger valve ports than the RM units.

[Julien D]

Heard great things from several boards on the conventional rm 125/250 forks from the 96-98 bikes(I think the years are correct...) These may be the same as the drz forks, I just don't know. cheap forks to find though...

I used to ride a 96 rm125 and nearly purchased a 98 rm250. Both bikes had just about the best suspension of any bike I ever had or got to ride. Those conventionals definitely kicked ass.

[kawagumby]

Factory X is right, the crappy 48mm Kayabas were used on the YZF 2004-2005, and are on the WR450 2005?-2011

Nope. The 48mm 04's were still single chamber like the previous 46mm forks and work well.

[factoryX]

My yz250 uses 46mm open chamber KYB's, and so far they've been very plush with trail riding, which is all I do.

[kawagumby]

For clarification, the 48mm 04 forks were "open chamber" vs the 05's which were the first year of the twin chamber. The 05's are considered by many to be avoided.