85 kdx200 drum brake to disc brake conversion?

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mwoj
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85 kdx200 drum brake to disc brake conversion?

Post by mwoj »

Has anyone tried changing the drum brake off a 1985 kdx200 to make a it a disc brake? Whats involved? My front rim is shot (cracked and bent), and I need a new (used) one. but I figure I might as well try the disc brake if its easy enough. What do I need? It will also make installing a vapor tech much easier (the spedo part)
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Re: 85 kdx200 drum brake to disc brake conversion?

Post by KDXGarage »

You could look into just getting a more recent KDX front end.
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pumpguy
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85 kdx200 drum brake to disc brake conversion?

Post by pumpguy »

I've never done this, but the hard part, IMO, would be mounting the anchorage for the caliper assembly. I suppose you could make a clamp on anchorage bracket for the fork slider, but that would involve some custom machining and fiddly assembly. I did something similar awhile back, but that was converting different type drum brakes.

Maybe later style forks that use disc brake would be an easier solution.
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85 kdx200 drum brake to disc brake conversion?

Post by mwoj »

Do you know if a newer style kdx fork will be a direct fit into the triple tree. Like will they just slide into the old ones spot? I could buy new front wheel with rotor, front brake cables/calipers/ lever assembly, and forks for around $350.... prolly not worth it. Anyone know how to modify original front spedo assembly to fit a vapor tech?
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85 kdx200 drum brake to disc brake conversion?

Post by pumpguy »

As far as fitting a Trail Tech Vapor computer goes, you will need to come up with a way to mount the magnet on the wheel and mount the sensor on the fork slider so the magnet passes close to the sensor with each rotation.

Bicycle digital speedometers work the same way, and have frequently been used on motorcycles too. For bicycles, they mount the magnet clamped to the spokes, although for a dirt bike, that's not too durable.

The usual recommendation for a drum brake hub is to epoxy the magnet to the spoke flange on the wheel hub. IMO, some sort of bolted or clamped arrangement would be better.

I have found Trail Tech to be very helpful with answering questions like this, and I would send them an email and see what they say. I would think you could find advise online via Trail Tech's website, or a You Tube search.
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Re: 85 kdx200 drum brake to disc brake conversion?

Post by kawagumby »

Hi,
The E and H model forks are a larger diameter than the '85.
However, as I recall, the 85 and 95 kdx200's use the same steering head bearings. I checked a vendor, and sure nuff, they are the same part numbers (double check to be sure).
So, what I would do is get an entire H model front end (H models are cartridge forks), triples and all from an H model kdx200 - they practically give the forks and front wheels away often, due to USD upgrades on those bikes ( I threw 3 sets of H model forks into the recycle bin not long ago)...so you should be able to get a set cheap. I also see them posted cheap on this site now and then. If you need the triples, get a set on ebay or here. The height of the steering head should be very similar, as the next C model (86-87-88) steering heads were a similar height to the H model and I don't see Kawasaki Heavy Industries changing things like that for no reason.
I bet you can find a setup for less than $150.00 or so for the forks and front wheel/disk, and about $50 or less for the triple. The brake calipers and hose can usually be had for about $50. Check ebay, but I'd put a wanted ad in this forum first.
So, once you've got an H model front set up with a disk brake, now what about the vapor? You don't use the original speedo at all. When you buy the vapor they provide a magnet that you can glue to the disk brake rotor at the appropriate location next to where you set up the sensor. They even sell the magnet separately for a small fee if needed.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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85 kdx200 drum brake to disc brake conversion?

Post by pumpguy »

If you're content with keeping the existing forks and drum brake, I would look into just replacing the rim. It's not all that difficult to do, just takes a little patience and knowledge of the truing procedure.

As far as the Trail Tech speedometer goes, I just returned from a visit to the antique motor cycle show and swap meet in Davenport, Iowa. On display there were several entries from the Cannonball Run. Some of these antique bikes were fitted with Trail Tech speedometers. Two of the examples I saw had their magnets mounted with a bolt hole drilled through the rear sprocket. Another one was fitted with light alloy full width drum brakes from a 125 Honda. On this one, the owner told me the magnet was secured to the front wheel's spoke flange with Gorilla brand 2 part epoxy.

Hope this helps.
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Re: 85 kdx200 drum brake to disc brake conversion?

Post by KDXGarage »

Those forks are the last variety of the 38 mm tubes. 1986 went to 43 mm.
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