1991 KDX 200 Rebuild

Nate1409 · Post by **Nate1409** » 06:08 am Sep 14 2016

Well done sir! Looking great.

ubareddition · Post by **ubareddition** » 07:22 am Sep 14 2016

Did you reassemble your bottom end yet?

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TheGriz · Post by **TheGriz** » 07:04 pm Sep 14 2016

I didn't split the cases. The oil that I drained actually looked ok, the transmission shifts smoothly, there is no vertical play in the crank and no sign of leaking past the crank seals. I'll probably wish I had refreshed the bottom end while I had the engine on the bench, but for now, everything seems ok. I'm waiting on a new governor shaft before buttoning the crankcase back up.

I did start to restore the wheels today. That is going to take some serious time. I've been debating about re-lacing the hub with new spokes and rim, but so far it looks like these might be salvageable.

Here is a before of the rear wheel:

ubareddition · Post by **ubareddition** » 07:08 pm Sep 14 2016

Bummer I was hoping your experience/ pictures would help me figure out why I'm having so much trouble.

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Friedom · Post by **Friedom** » 07:27 pm Sep 14 2016

ubareddition wrote:Bummer I was hoping your experience/ pictures would help me figure out why I'm having so much trouble.

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What are you having trouble with?

"Good job, guys. "

ubareddition · Post by **ubareddition** » 07:30 pm Sep 14 2016

Friedom wrote:
ubareddition wrote:Bummer I was hoping your experience/ pictures would help me figure out why I'm having so much trouble.

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What are you having trouble with?

"Good job, guys. "

Check my other thread "a few questions about my 94 kdx 200"

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TheGriz · Post by **TheGriz** » 08:04 pm Sep 14 2016

I'll post more wheel pictures soon... I needed a night away from the workshop. I've been letting my radiator hoses soak in a dawn and water solution for the past couple days. It made cleanup quite easy.

Not perfect, but good enough for this old girl.

ubareddition · Post by **ubareddition** » 08:06 pm Sep 14 2016

So much good info here. Thank you!

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TheGriz · Post by **TheGriz** » 11:30 am Sep 15 2016

Masked off the wheel bearings (which are still good) and blasted the entire wheel: This takes some serious time to get each and every spoke. It isn't perfect, but will work. I'm still on the fence about re-lacing the wheel with new spokes and rims. I just don't want to spend that kind of money. I realize there are ways to refurbish wheels without abrasives, but I don't have that kind of patience.

After blasting the wheel. I did some wet sanding with a foam 220 foam block and a spray bottle of dish soap and water. That was followed by more wet sanding with steel wool. The spokes are steel and to prevent the rust from creeping back so fast, I'll clear coat the entire setup.

I also hit the rotor with an orbital sander. It might still be useful.

TheGriz · Post by **TheGriz** » 06:02 pm Sep 15 2016

Front brake caliper is a mess:

I'm not exactly sure what this rubber goopy mess is. Perhaps a swollen rubber basket or silicone?

Removed the pads, which looked to be in decent shape.

Self centering plate and rubber bits removed:
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Air pressure in the brake line hole. Popped the piston right out.

I blasted the parts, carefully masking off the piston cavity. I don't want to mess with the machined surfaces. The piston just got a clean up in the parts washer:

TheGriz · Post by **TheGriz** » 08:24 pm Sep 15 2016

I purchased the wrong rebuild. More front caliper rebuild pics in a week or so. I'll move onto the rear caliper and master tomorrow.

Post by **KDXGarage** » 03:26 am Sep 16 2016

This is great. Thanks.

TheGriz · Post by **TheGriz** » 12:10 pm Sep 16 2016

I'll do a step by step for the rear caliper. Maybe people would appreciate a little how-to:

Started by removing the caliper from the slider bracket:

Next remove the brake pad retaining pins. Both of mine were frozen in and stubborn. One pin required multiple heat cycles with the torch followed by penetrating oil. I inserted my allen wrench and smacked it in with a hammer. This loosened it up enough to remove it with the allen wrench.

The other pin was not giving up as easily. I used a trick that I learned from an old machinist at my work. I started with a small left hand drill bit and slowly worked up in size, until it was almost the size of the threads. I was patient and finally the drill bit spun the pin out of it's home:

Remove the pads and separate the caliper halves:

Leaving the bleeder valve in place, I used the air pressure trick to pop out the piston. Not shown in the picture, but I place a rag in the piston to avoid it shooting out and damaging the piston or the caliper.

Removed the spring clip:

Followed by the o-rings inside the caliper:

Pulling out the rubber boots:

And the bleeder:

I cleaned all the parts using the same techniques that I used on the front.

TheGriz · Post by **TheGriz** » 12:33 pm Sep 16 2016

Time to rebuild the rear caliper. I am using a kit from All Balls (1542740007).

Install the o-rings into the grooves. It is pretty obvious as to which one goes in which groove. I always apply a little grease to help the piston go in without tearing the seals.

Carefully, push the piston into the hole. It must go in squarely. If it bound up, use air to remove it and try again. Resist the urge to use pliers to pull it out.

There are a couple caps that go over the end of the piston:

Insert the spring clip:

Insert the end clip and start to install the new rubber boots:

I use moly lube on the pins and inside the boots to help keep them operating smoothly.

Reassemble the two halves together:

Time to reinstall the pads and pad backer:

The rebuild came with new pins. You may need to push the pads into the spring clip to get them to line up with the pins

Reinstall the bleeder and new rubber cap:

Reattach the caliper to the slider bracket and you're done. I'll use the new compression washers when I install the banjo bolt and brake line.

david · Post by **david** » 12:45 pm Sep 16 2016

The 'rubber, goopy mess' on the front caliper was/is the dust seal. I've seen it before on caliper bolt bellows and bleeder screw caps.

TheGriz · Post by **TheGriz** » 01:04 pm Sep 16 2016

Makes sense! Thanks.

TheGriz · Post by **TheGriz** » 09:59 pm Sep 19 2016

Started rebuilding forks tonight. New seals, wipers, bushings, and fluid! Swapping in some springs for a 200lb rider.

TheGriz · Post by **TheGriz** » 12:04 pm Sep 20 2016

Forks rebuilt and resprung. Shock cleaned up and resprung. I have the seals to do the shock, but it might be ok. Doesn't appear to be leaking any oil and feels fairly smooth.

TheGriz · Post by **TheGriz** » 11:39 am Sep 21 2016

I pulled the wheel bearings and am glad that I did. There was a lot of trash and gunk in there. While there wasn't much play in the bearing, it wouldn't have been long before they did.

Still waiting for some critical parts:
Cylinder and Piston to return from Millennium
Governor Shaft
Front caliper rebuild
Front and rear wheel bearings

New radiators from China arrived today. I guess I'll keep the stock banana rads as spares.

TheGriz · Post by **TheGriz** » 09:57 pm Sep 21 2016

Started working on the new governor/powervalve shaft. Since I can't find one anywhere, it is time to make one. Luckily my buddy Jon has a machine shop. Still need to mill the flat in the other end and drill/tap a couple holes, but ran out of steam tonight.

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