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1986 kx250 restoration

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Finished my 1986 kx250 restoration. The bike sat for 8 yrs in someone's backyard. Didn't run. This bike was a huge chore to restore

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I love those bikes. Last year for the real uni trak. You did a great job. I understand the work that goes into a project like yours. There are so many little things that Kawasaki factory did back then that was works bike trick and we didn't appreciate it. Like the adjustable fork preload. Or the way it's almost a 2 piece front axle not just a nut spun on the end. I have a 125 and really want a 82 to 86 kx250 next.

Did you buff out the tank? It looks in great shape. I hope you are going to race it

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MaxPower, first, thank you very much. But I did light buffing to the tank. The tank that came with the bike had 15 yr old stickers on it so I had to find another one on ebay. One thing about the old kawasaki's is that parts are super hard to find. I restored a 1986 CR250 a few months ago and parts were more readily available for the CR

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 Last year for the real uni trak. 

 

 

That's a good thing. :lol: 

 

Kawasaki really blew it with the geometry of that design, it actually had a falling rate instead of a rising rate. It was as bad as Suzuki's Full Floater was good.

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On all uni trak with rocker arms or that year?

 

 

I believe they actually changed the geometry in something like '83 or '84, and finally managed to give it a rising rate. It's been so long now I'm not sure when the change happened.

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I owned a Floater in 81. Ridden the 82 83 and 84 KX125s and the rear of the Kawasaki were darn near as good as the Suzuki.

What year KX did you own that was so bad?

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I owned a Floater in 81. Ridden the 82 83 and 84 KX125s and the rear of the Kawasaki were darn near as good as the Suzuki.

What year KX did you own that was so bad?

 

I thought my '83 KX125 was atrocious. And not just the suspension, the '83 KX125 had a frikken grenade for an engine. It was fast as shit, 'til the crank broke, which happened with alarming regularity. It was so bad Kawasaki had to de-tune them for '84 to get them to live. No 125 before then had ever turned the kind of rpms that year KX125 did (they revved out to about 12,500 rpms which was unheard of at that time), and the metalurgy of the day just wasn't up to the task.

Edited by Chokey

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That is crazy that the same bike can have experiences at opposite ends of the spectrum . I liked the 83 so much I have one now for vintage racing.

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Finished my 1986 kx250 restoration. The bike sat for 8 yrs in someone's backyard. Didn't run. This bike was a huge chore to restore

 

CONGRATULATIONS!!  It looks nice.  You have done a very good job.

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Chokey, 1986 was the last year the KX 250 had the redundant uni-trac system. Kawasaki finally got smart in '87. Plus, I think '86 was the last year without a detachable sub-frame on the kx250. Like i said earlier, I did a restoration on a 1986 CR250 too and both being an '86....The CR is so much a better bike. Way more advanced. And the parts are much easier to find nowadays for the old CR

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Here is the 86 cr250 that I recently finished restoring. ...

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Chokey, 1986 was the last year the KX 250 had the redundant uni-trac system. Kawasaki finally got smart in '87. Plus, I think '86 was the last year without a detachable sub-frame on the kx250. Like i said earlier, I did a restoration on a 1986 CR250 too and both being an '86....The CR is so much a better bike. Way more advanced. And the parts are much easier to find nowadays for the old CR

 

 

Yes, I know '86 was the last year for the above-the-swingarm  pushrod/wishbone design. But there was a geometry change somewhere in the middle of the years they used that system to take it from a falling rate to a rising rate.

 

The original KDX175 was even worse than the KXs with its falling rate and was REALLY bad. The KDX didn't get the rising rate until it became a 200.

 

During that era, Suzuki's Full Floater was hands down the best rear suspension on the track, and would still be considered good today. The only reason they switched to the current under-swingarm design was cost and weight.

Edited by Chokey

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During that era, Suzuki's Full Floater was hands down the best rear suspension on the track, and would still be considered good today. The only reason they switched to the current under-swingarm design was cost and weight.

I have always thought the reason Suzuki did away with the Floater was design infringment issues

My opinion of the early Uni Trak isn't as harsh as yours. The 175 I raced wasn't a floater but it wasn't a mono shock either. Maybe the 175 you rode wasn't set up for you. But there weren't too many settings to change. It never would kick me off . Cant say that for my IT. . The entire 81 KX 250 was horrific. That is a bike I would never care to ride again. The 82 ,83 and 84 KX125 were good bikes. (I loved that 1984 KX125) Good enough that I ditched the 82 RM125 i had for vintage racing to buy my 83 KX.

Not that magazine tests are the final word or opinions hold more water than anyone else , but I never remeber the KX rear suspensions of that day being called the worst of the bunch. I'm old now, I could be wrong. But there are times I can recall jetting specs from 1979 but lose my keys. My opinions. Everyone looks at situations from thier own point of view and experiences . Im just a little surprised as no one I new disliked the Uni Trak as much as what you are sayng. We completely agree that the rear end of our Suzukis were great. Is there anything printed sayng how bad the KX was? I'm not being a douche. I would like to see it. But maybe I won't too. I like my bike now and reading that might get in my head.

pBegley, your 86 Honda couldn't look better. The 85 CR was my last dirtbike as a kid. I didn't ride again until I became a full blown adult years later. The gold rims made the 86 bikes stand out. Do you ride these bikes? I know the Hondas were more refined, but I like the KX now because they are more rare. And I like their styling better. Maybe Lechines look those years help me form that opinion. You did a great job on both of them. Do you plan on doing it again? After restoring my bike the next vintage bike that comes to live in my garage will be bought as a finished product

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I didn't dig up anything much about the rising rate (or lack of) on the KX models, although I'm sure I could if I tried harder. But I did find a reference to the falling rate of the KDX175:

 

http://www.dirtbikemagazine.com/Me2/dirmod.asp?sid=&nm=&type=news&mod=News&mid=9A02E3B96F2A415ABC72CB5F516B4C10&tier=3&nid=4B35F3B5FBEB45D79F6C9E17584AD07D

 

"Oddly enough, the 175 had a regressive rate."

 

My '83 125 would kick me off with regularity in both braking bumps and acceleration bumps, and no amount of suspension tuning (not that you could do much to it back then) ever seemed to rectify the problem. The suspension would blow through the stroke and pack down and just hang down there.

 

This is all I really found on the KX having a falling rate:

 

http://motocrossactionmag.com/news/death-of-the-rising-rate

 

This endless merry-go-round of leverage ratios started in 1980 (when Kawasaki’s Uni-Trak system was introduced to the public, only to turn out to be a falling-rate rear suspension system)

Edited by Chokey

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You guys obviously know more about dirtbikes than me. I just know how to ride and how to fix em

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You guys obviously know more about dirtbikes than me. I just know how to ride and how to fix em

 

 

Well, I know a lot of trivial BS like this just because I've been riding and racing and wrenching for over 40 years. But trivial BS isn't really all that useful other than for telling stories. :lol:

 

I do know a bit about wrenching and riding too though... :smirk:

 

And I also don't mean to take anything away from that beautiful restoration job you just did. That's an outstanding job and I really hope you enjoy that bike.  :thumbsup:

Edited by Chokey

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I am still learning all that "trivial BS". I rode when I was a kid in the 80's then didn't ride again until '03. I just recently started working on them within the last year....because I love dirtbikes and don't always have time to ride....but I can always make time to wrench in the garage. At least my wife can't get mad because I'm home...and near the kids

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