franken bike suspension advice

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franken bike suspension advice

Postby Hario » 11:07 am Mar 04 2017

Hi All,

Ive been fixing up a bit of a rough 89 kdx200 SR i bought at the end of last year, the bike is generally in good shape but has had both the front and rear suspension swapped in from other bikes. I'm going through the process of sizing up my options for getting the bike in good shape and could really do with some advice and help from people familiar with these bikes (ive not had a kdx before)

here is my franken bike as she stands:

Image

the forks seem to be from a KDX250, possibly an SR as they are gold anodised and most seem to have been blue. They seem incredibly soft, have zero adjustability and the aluminium is pretty rotten so they need to go!

If i were to put stock kdx200/220 fork back on Im wondering if there is a particular age of bike to go for, or avoid? i noticed the older bikes have a single pot brake vs 2 pot on the newer ones, do the brake caliper and hangers interchange between years. i.e. are the fork castings the same? like wise are the fork yokes/clamps the same across years?

im also wondering if anyone knows of a fork swap for a diffent USD that would use much of the KDX250 stuff ive got on my bike already, it would be brilliant if theres an adjustable KX fork that would use the same clamps wheel and brake for example, that could save me a lot of time and money!

it would help me out a lot if anyone knows the length of, or could measure the stock fork leg, from the centre of the axle to the top cap. i have most of a front end from a 96' RMX250 (the year it got 45mm conventionals) i could graft on, but don't know if these forks are way to long or short vs the stock ones without any numbers to work with



The shock is an ohlins, i found a part number off it and its from an early 00's gasgas Ec, im not sure which model exaclty. Does anyone know if this is likley to have been a straight swap? i dont really want to get into messing with the bikes geometry and linkage etc, so if its going to be an involved job getting it working ill probably just source a KDX shock. From my reading it sounds like they work perfectly well

also, if anyone has numbers from setting up the sag on a stock shock lying around it would be really helpful for me to figure out if this one has been done properly already, likewise if anyone could tell me the kdx shock length to bolt centres that would be brilliant and would save me a ton of hassle.

Sorry about the barrage of questions! but i would massively appreciate any help getting this bike in shape, im itching to get riding it!, and would really value any advice from you seasoned KDX vets on what might be a smart route to take.

and for what its worth ive no interest in bling factor, i just want the bike at its best :lol:
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Re: franken bike suspension advice

Postby Jason » 02:09 pm Mar 04 2017

Search for posts from jaguar on OHlins Gas Gas comments.

On the forks, can you take a pictore of the fork caps, bottom of the forks, front hub and braking area to help identify them? Some KDX SR200's had USD forks.

Can you also measure the fork inner tube diameter?
Thank you, Julien D for all your hard work!

PLEASE! Do not "dip" PWK Keihin carbs in Berryman's to clean them! It will damage the internal o-ring (jet block gasket).
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franken bike suspension advice

Postby Hario » 05:07 pm Mar 04 2017

its this distinctive line in the fork leg that gives them away, you can also see the lower clamp has a single pinch bolt, which looks like another giveaway:

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as modeled on this sporty number:

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shame they didn't bodge on those plastics too, nothing makes a statement like riding around town on your mint and pink 2stroke :shock:

the axle, brake and caps:

Image
Image
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Other than the line they look very similar to KLX250/300 forks?

i haven't measured today, but if my memory serves the stanchions are 43mm
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Re: franken bike suspension advice

Postby Jason » 06:10 pm Mar 04 2017

They may be the standard forks, as the 1990 model came with USD forks. The top clamp in the USA had the solid mounts. The KDX250 had rubber mounts. If they are 41mm then that would confirm stock forks.
Thank you, Julien D for all your hard work!

PLEASE! Do not "dip" PWK Keihin carbs in Berryman's to clean them! It will damage the internal o-ring (jet block gasket).
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franken bike suspension advice

Postby Hario » 04:25 am Mar 06 2017

They are definitely 43mm:

Image

This is the forks length from the top cap to axle centre, with the weight off the bike:

Image

Does anyone have the same measument for the stock KDX200/220 fork? it would really help me out!

Also, with the help of my wife (shes Japanese) i managed to find parts diagrams for the SR models. Sorry about the low res pic, but its looks like the SR versions had cast handle bar lowers the same as mine

Image
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Re: franken bike suspension advice

Postby Jason » 02:23 pm Mar 06 2017

OK. Them maybe they are KDX250 SR forks. Most forum members are from the USA, and we did not get the SR version, so there it's not a lot of info on here about them.
Thank you, Julien D for all your hard work!

PLEASE! Do not "dip" PWK Keihin carbs in Berryman's to clean them! It will damage the internal o-ring (jet block gasket).
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