yz426 conversion query

Questions and comments about converting to beefier forks..
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kdxdazz
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yz426 conversion query

Post by kdxdazz »

i have a yz426 thats been sitting under the house for the last 15 years, i purchased the bike new and spent over a thousand dollars on the suspension,revalved for my weight,gold valves,reactive springs, rear shock done too. think its worth putting them in my suitcase and bringing them to thailand to put on the kdx220. i have 2 questions, the consensus seems to be use the yz426 front wheel but why is this, i would prefer to use the kdx wheel so i can keep the speedo drive. 2nd question is can the yz rear shock be used on the kdx. i know the bottom is different where it bolts to the linkage but can this just be swapped over, the shock needs to come apart anyway for new seals so can machine things down if need be
1999 KDX220SR (KDX220-B5)
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bufftester
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Re: yz426 conversion query

Post by bufftester »

While you can probably make it work, there are a couple things you'll need to know beforehand. Overall length of the shock uncompressed (center-to-center of the mounts) the mount hole diameters, and the width of the mounts. These are all manageable to a point. You can use bushings for hole diameters if needed, can take a couple of mms off mount width with no ill effects, and can adjust stroke length on the shock internally possibly. Without knowing those 3 bits of info it's hard to say how much work it would be.
kdxdazz
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Re: yz426 conversion query

Post by kdxdazz »

yes good points, i thought it might have been a conversion that has been done many times before. my yz426 shock already has an internal spacer to lower it, i will remove both and put side by side and see if it can be done, just thought it might be a good idea rather than rebuilding the kdx shock only to find out later that there are much better conversions to use
1999 KDX220SR (KDX220-B5)
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kawagumby
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Re: yz426 conversion query

Post by kawagumby »

As far as the wheel issue goes, the reason you should use a yz wheel is the axle sizes are very different. You can bolt up the kdx brake caliper directly to the yz forks if you switch out the caliper bracket for a yz bracket. Even using the stock length yz forks will work if you use handlebar risers or fatbar adapters. The only issue some people have is widening the fork turning stop so the forks don't hit the gas tank, but that's an easy fix if one simply welds a slightly wider piece of steel to the existing stop. As you probably know, you will need to press out the KDX triple stem, have it widened with knurling (most stems) and press it into the yz triple. BTW, the stock KDX shock is very good, better than most MX shocks for off-road and if fitted with a gold valve is as good as any modern enduro shock.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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oldmxer95
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Re: yz426 conversion query

Post by oldmxer95 »

A good solution to the steering stop issue is to use a KX250 lower clamp. I used one from a 98. The Yamaha forks slide right in.
95 KDX 200H, 98 KX250-K5, 84 KX125-C1(Project), 21 Husqvarna FX350
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kdxdazz
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Re: yz426 conversion query

Post by kdxdazz »

kawagumby wrote: 08:18 pm Jan 12 2020 As far as the wheel issue goes, the reason you should use a yz wheel is the axle sizes are very different. You can bolt up the kdx brake caliper directly to the yz forks if you switch out the caliper bracket for a yz bracket. Even using the stock length yz forks will work if you use handlebar risers or fatbar adapters. The only issue some people have is widening the fork turning stop so the forks don't hit the gas tank, but that's an easy fix if one simply welds a slightly wider piece of steel to the existing stop. As you probably know, you will need to press out the KDX triple stem, have it widened with knurling (most stems) and press it into the yz triple. BTW, the stock KDX shock is very good, better than most MX shocks for off-road and if fitted with a gold valve is as good as any modern enduro shock.
Ah thanks that makes sense, the reason I want to avoid the YZ wheel is all the parts need to fit in a suitcase to take back to Thailand with me. Is it possible to change out the bearings on the kdx wheel to suit. I've ordered the shock seal head for the kdx rear shock and plan to do a full rebuild on it and get that set up before deciding on using my YZ shock
1999 KDX220SR (KDX220-B5)
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kawagumby
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Re: yz426 conversion query

Post by kawagumby »

The KDX wheel won't accept the larger bearings. However, if you're not against taking a wheel apart, I've used KDX rims with the YZ hub and spokes a couple of times...you need to use the YZ spokes with the KDX nipples for the best fit. If you can pack the hub and spokes, you should be OK.
1994 KDX200, Beta 200rr, yz125, yz250, kx100 modded for adult, gasgas contact 250.
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