Air Cooled KDX Section

Reference and discussion for the various air-cooled KDX models
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Julien D
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Air Cooled KDX Section

Post by Julien D » 06:26 pm Mar 15 2012

You asked for it, you got it. :mrgreen: This section will be devoted to reference material, experiences, recommendations, parts lists, general information, and tips and tricks for all air cooled KDX models. Let's keep the general Q&A out in the general Q&A section. If anyone has some good documentation or wants to write an air cooled KDX FAQ or anything else that you feel deserves to be stickied here, let us know in the "Ask the moderator" section.

If you're lucky enough to own one of these, please share your personal expertise!



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Post by fuzzy » 08:30 am Mar 16 2012

'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project

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Post by Redrum » 08:36 am Mar 16 2012

Sweet just picked up an 88 a couple days ago. THX guys
88 kdx 200
85 atc 250x
86 vf 500
08 cbr 125r
79 ke 175
97 sportster 885
86 virago 535
79 yz 125

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Air Cooled KDX Section

Post by Zetracks » 03:28 am Jul 29 2012

I've owned a 1983 A1 from new.
Now has 86 front end.
Own 4 stroke 450, too heavy for my older body, especially in gnarly woods and rocky or slow sandy stuff.
Going to get the 200 up to scratch again,
1 Rebuild rear shock or replace with ???
2 If rebuild, is there a slightly heavier spring or kit available. I've checked Fredette & I can't spot anything.?
3 Can I gold valve the 86 front forks and add a progressive spring or get a more modern front end?
4 Cheapest and easiest way to fix slipping gear lever?
4 I may put a rear disk on as I have most of the bits, from other posts it seems the disk hub may fit, any comments?
I have always loved this bike and it has looked after me on many close calls, time to return to it and give a freshen up if viable.
Still goes like stink!!
You have just got to love these nimble, shure footed, easy to work on, reliable, giant killers.
BTW Between my mates and I, we have 4 air cooled (owned since the 80s) and 2 watercooled, KDXs. All are in above average to very good, fully set up condition. We had a retro 2 day last weekend, all bikes were there and we fell in love again, hence the freshen up.
We live in Western Australia (Lots of forests and hilly, rocky trails) and not one of us would sell our much bragged about KDXs

Kawasaki 1000RX, Bullet proof engine
Kawasaki KDX200, 86 front end
Honda CRF450X, set up for Long Hauls & overnighters
" Air Cooled Rules "

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Re: Air Cooled KDX Section

Post by kawagumby » 08:38 am Jul 29 2012

If your shock body isn't worn out I'd just rebuild it or have it rebuilt (if it is a rebuildable type) A new KYB seal, new oil and charge and you're set. The spring is something you'll probably have to figure out by dimension - diameter, length and rate and search that way rather than bike application.

If you already have an 86 front end you can upgrade to an H (95 up) model (cartridge) std forks with dual caliper brake by swapping out the forks, wheel and caliper - the fork diameter is the same as an 86. The front ends are pretty easy to come by due to all the USD swaps people do. LOL, I have three sets of stock forks I don't know what to do with.

I agree about the 87 is very light, probably around 215 dry with aftermarket pipes and other mods - it feels noticeably lighter than my H model KDX's and is more flickable in the twisties. LIke you, I'm getting along in years and a light bike is one way to extend the riding experience - with a plush seat too! :mrgreen:

slipping gear lever? Do you mean the shifter splines are worn? If so, I'd spot weld it. Just enough to hold because you might want to grind it off and replace the shaft later.

For a permanent fix, you might want to look at ebay offerings, as the early KDX's and KX125 shared a lot of components. I'm building a spare engine for my 87 and the shifter shaft spines were shot. I looked at the shifter mechanisms on the 125's and they looked the same, so I gambled and bought an 84 KX125 shaft. I turns out it was the same except 3/16" shorter - which is just fine - it will work perfectly (I couldn't find a good KDX shaft for cheap). To change it out requires pulling the clutch ass'y out to clear, otherwise an easy task.
1994 KDX200, Beta Xtrainer, 2 yz125's, kx100 modded for adult, cf150rb modded for adult, gasgas contact 250.

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Air Cooled KDX Section

Post by KDXGarage » 09:24 am Jul 29 2012

Rebuild the shock. If you can find a spring, if it is a big rate change, you may want to consider getting the shock revalved. Maybe there is a place like in AUS.

If you stick with the 1986 front end, go with straight rate springs. The Race Tech Cartridge Emulators will work.

You could also get a 1995+ front end for not a lot more money.

If the shifter shaft is worn, I don't think much more than replacement in order. Be sure to use Loc-tite next time around.

Good luck with it!
Thank you Julien D for all your hard work!

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New to me, A1 Model

Post by torgo » 08:40 pm Aug 25 2012

I just scored a 1980 A1 model. I love craigslist. :boogie:

It looked rough but after I got it home and cleaned it up it looked all right. Plastic is toast except for the tank.

It will need new fenders, and side covers. PO thought the transmission was toast but it turned out that the bearing for the clutch was gone. I ordered one but for now I turned an aluminum bushing for now until it gets here. I changed the oil and cleaned the carb and kicked it to life on the 4th kick. The clutch plates were stuck together and it took a little bit to get them break loose.

I have ordered brakes, wheel bearings, fork seals and cables. The rear suspension is really tight. I am going to strip it down and lube it but I think all the bearing are good.

I would like to put on an aftermarket silencer as the original (which it has) is very heavy. Who knows what will fit? :?

Also it seems really flat off the bottom. I am having a hard time getting it to wheelie. Is this a jetting issue or just how the old air cooled motors ran? :hmm:
Sorry honey it was an impluse buy.

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Re: Air Cooled KDX Section

Post by torgo » 12:29 am Jan 01 2013

I did some work on the 175, new trials tire on the rear, new rear brakes, wheel bearings, stripped and lubed the rear suspension, new x-ring chain and sprockets. Rear suspension is really tight and all bearing were good just dry. New front wheel bearings, new front brake pads, new front brake cable, pro-taper bars, MSR hand guards, bar risers.

I put a new O-Ring in the exhaust pipe. I have ordered a new throttle and grips.

I started it today and it ran pretty well, smoked a lot on start up and after I rode on a mile loop when I got back home it would not idle down.

I plan on getting a new intake manifold and reeds. It has good compression but I have not pulled it down to see if it has the original bore.

I am thinking of just doing the entire motor. I just want to send it off and get it all done. Who would be the best to rebuild my 175?

I want to take it to 182cc and do the main bearings, seals,rod bearings; the works.
Sorry honey it was an impluse buy.

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Air Cooled KDX Section

Post by Jimmyjoe41 » 06:16 am Dec 30 2015

hi all im in northern ireland, uk. i have an 86 kdx 200. i race it in the classic mx here. the engine runs pretty sweet but wont idle. i have an inline fuel filter cause the carb kept blocking which was a real nuisance. the main issue is the front shoes. i cant seem to find the right ones online. most 86 c1 models had discs on the front where mine has drums which i need to race in the classics. the forks also have kx125 stamped on them. i had the forks rejuvinated last year and the suspension guy had to order seals by size as he couldnt find out which model the forks were from. the shoes measure up to be 110 x 28mm which seem to be from a kx80 which seems strange on a big bike. any advice will be appreciated.

i got the rear suspension regassed but would like to change it to a more mx geared shock. any advice would be great thanks

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