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I got myself a nice shiny set of 2001 DRZ 400 forks. Way burlier than the KDX units. Now working on a triple clamp. If anybody cares to know, they use the same axle and wheel as my 07 WR 450. I did not know that until I compared them to the WR. They have the same caliper mounts too. I plan to use my spare WR axle and wheel for the fork swap, and will get a WR caliper to make sure it fits the rotor diameter.

Now to figure out what to call it....KDZ, no, KDW, no, KRR, no, KOW...maybe

I bet you will like it :)

Been debating this swap for a while now, post pics please.

Aren't DRZ forks still the conventional style?

gsa102 wrote:I got myself a nice shiny set of 2001 DRZ 400 forks. Way burlier than the KDX units. Now working on a triple clamp. If anybody cares to know, they use the same axle and wheel as my 07 WR 450. I did not know that until I compared them to the WR. They have the same caliper mounts too. I plan to use my spare WR axle and wheel for the fork swap, and will get a WR caliper to make sure it fits the rotor diameter.

Now to figure out what to call it....KDZ, no, KDW, no, KRR, no, KOW...maybe

DRKDX has already be taken by some old guy back east who still races on occasion

Yes, they are conventional. Supposed to be really good woods forks. I will post pics and details when I get the triples and the real work starts. I am tickled that the WR stuff fits, because I can use the big WR floating wave rotor. Stoppies, anyone?

The DRZ triple clamps arrived today. The set I bought came without the stem, so one less step for me. So I pulled the old forks and triple off of the bike. I will take them to my father's farm tomorrow and press the KDX stem out. With some luck I will press the stem into the DRZ lower.

I looked things over and noticed a few things, good and bad:

The 7/8" handlebars will fit.

The fender holes are completely wrong, will probably be best to get a new one and drill new holes.

The KDX brake caliper may work without modification. It is very similar to the WR caliper. The hole spacing is right on anyway.

The steering stops need to be built up. I can weld a tab on the steering head.

There is minimal clearance around the bottom of the steering head for the DRZ triple. It looks like it will need shimmed down under the bearing, or ground out.

I will update as I make progress on the triple clamps. After that it should go pretty fast...

I pressed out the stem, it took some heat on the bottom clamp to get it loose.

I used an inexpensive digital caliper to measure the parts.

KDX stem - 1.181" at the clamp / bearing seat.

KDX clamp - 1.177" - good tight interference fit

DRZ clamp - 1.188" - 0.007" too loose. I will do some research on epoxy and bonding agents and try to find something suitable, or have it knurled.

The lower bearing measured 1.180, which I think is a little too tight. I will mock up the clap tomorrow and check to see if any shims or collars are needed.

If I recall the KDX stem is thicker below the bearing. That is why the stem needs to be turned down when doing a KX fork swap so the bearing will seat flush with the lower triple.

Did you press out the KDX stem yet?

Yes, I pressed it out yesterday. I measured the clamp fit and the bearing fit on the stem, and they were the same, as close as the caliper would measure. At least it was round, both of the clamps were slightly oval.

I found a bearing mount compound from Permatex, # 20297, which is good for a slip fit up to 0.020" for $6.99. Bad thing is I had to order it from the local auto parts, and will probably take a week to ship in. I was going to use a loctite retaining compound, but would have had to special order that, so I went the cheaper route.

I am headed outside to mock things up to see what fits.

Did the mock up today and have pictures:



The top clamp stem bore needs shimmed down maybe 1/8" to tighten it up on the stem. No shim needed under the top clamp. No mods needed on the lower clamp, except to build up the steering stop on the frame.

The KDX brake caliper fits perfectly. My WR axle is too short, as are the spacers. The axle clamps are about 3/4" wider than on the WR.



Now to get more parts. Need a fender and axle. I will get a tube and spoon on my snow tire with screws for some winter fun when I get finished.

Freaking monsters.

Got the retaining compound yesterday, and took everything apart to put the steering stem and the lower clamp in the house to warm up.

While taking the clamps apart, I noticed the nut that preloads the bearings was only engaging about 1/2 of its threads, because the lower clamp must be thicker than the original.



I plan to grind or machine the bottom of the nut to gain a couple extra threads. Any other ideas?

I had a buddy with a lathe mill the top of the nut, so I could turn it over with the threads down to get full thread engagement. I also took a 7/8" SAE washer and had the center milled out to fit over the bottom of the nut to spread out the load under the top triple clamp.



Here is what it would look like assembled:



The red arrow indicates the area where the top triple would fit over the steering shaft. The stem is about 0.060" too small to fit the top triple. My friend gave me a strip of 0.010" brass shim stock to wrap around the stem, like tape, to take up the clearance. Now to glue the stem in and assemble everything - after deer season...

Cost so far:
$76 forks, delivered
$36 triple clamp, delivered
$8 - small tube of permatex retaining compound
$10 - to my friend for machine work
$130

Here is a picture of the triple clamp with the shims wrapped in the center. (the wife was making xmas cookies - YUM)



It took two wraps of the 0.010", and one wrap of 0.008". So the total shim thickness is 0.056". Three wraps of 0.010" or 0.060" was too much to get to go together.

I changed the oil in the forks and installed the triples and the forks on the bike. Just waiting for my axle to arrive....

Gluing the stem in with the retaining compound was really easy. I assembled the forks in the clamps. I then wrapped the top of the stem below the threads with electrical tape to keep the stem centered. I applied the compound to the base of the stem and the lower clamp, twisted it in, and turned the top nut on finger tight to hold it in place while it set. I was very happy with how the stem alignment turned out.

I couldnt resist putting it all together today. I put the tire on the rim and used my WR axle which is still a little short. To get the axle to crown distance right the forks stick out 5/8" to the bottom of the cap. I still have to get the right axle and have an extra spacer made for the brake side. I used washers for now, but they are a tad too thick combined. No extra spacer needed on the non-brake side.



SO I had to take it for a test ride - in the snow. It felt pretty smooth, but I haven't been on it in a month. I am waiting for the ground to freeze up and get rough, for a real test. I went over a couple small jumps in the yard and slammed the wheel down, and the spring rate seems about right. It just almost bottomed. The brakes work better with the bigger rotor.

Now for the fun part - Ride and ride some more...

Awesome!
Question, How'd you mount the fender?

gsa102 wrote: To get the axle to crown distance right the forks stick out 5/8" to the bottom of the cap.

My concern with this is that you've had to slide the tubes up too much. While it is important to set the front ride height correctly, conventional forks present a potential problem greater than what a USD fork presents when raised too high. On a USD fork, with the forks raised too high in the clamps and full suspension travel is reached, the tire will rub the bottom of the fender, potentially dangerous. On a conventional fork, with the same scenario, not only will the tire rub but the outer tubes will contact the bottom of the lower triple clamp, dangerous and potentially damaging to the equipment. In order to run these forks in the raised position needed for proper front ride height you may need to have the travel reduced internally.

Fletch, I thought I could get a green KLX fender, but no luck. I had to "egg out" the old holes with a drill bit to get the KDX fender to fit. I traced a pattern out on paper while still apart to find the centers, then ground out what was needed for a custom fit.

Chopper, thanks for the input. I will take the springs out and collapse the forks, wheel on, to see if that is possible at the current setting. I will adjust as needed.

I ran extra sag in the rear to keep the bike in balance with the old forks, so I had planned to adjust the rear sag to get the bike back in balance anyway. It may take some ride testing in better conditions to find the optimum fork height setting after adjusting the rear. I will have them shortened if necessary.

I dont know if it is just me, but at the recommended sag the rear seemed pretty stiff (with the proper spring for my weight). Backing it off a couple turns sure softened it up, but then it would bottom. Maybe it also had something to do with the geometry on the soft front end.

Now just need some nice SHOWA stickers for on the forks...