89 KX80 rebuild

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5/31/2018 1:47 PM
Edited Date/Time: 5/31/2018 2:13 PM

Hello ya'll! I picked up a 89KX80 Big Wheel out of a barn here in Texas and I've been slowly rebuilding it over the past couple of months. The cylinder and crank need to be rebuilt. I'm sending it up to Millennium Tech in Wisconsin and I would like to know some opinions on if if I should stay stock 80cc or go big with a 90cc Wiseco kit along with their performance cylinder package (replate, port polish).

Part of me wants to keep it stock but I've already had to go aftermarket with the radiator and several small things like suspension bearings, fork seals, steering stem bearings and a Pro Circuit silencer.

I'm going to be riding it very occasionally and not very hard. Parts for this thing (Plastics) are just too hard to find and too expensive. Thanks!

https://pix.watch/eqmnnd/FJbGDe.jpeg
https://pix.watch/3Qm5ed/IKWZiH.jpeg

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6/1/2018 6:00 AM

Please upload your pics to Vital using the Upload Photo option.. these third party pic hosting sites always go away after a few years and then we can't see your cool pics anymore.

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Ride like a girl!!!
Insta queenofspodes
2017 KTM 250 SX build thread
2016 KTM 500 EXC-F
Current project: 2007 Kawasaki KX250-R7 retro build
Current project #2: 1987 Kawasaki KX250-E1 rider/racer resto
1989 KX125 resto
1987 RM250 resto

6/1/2018 6:58 AM

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6/1/2018 7:01 AM

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6/1/2018 7:06 AM
Edited Date/Time: 6/1/2018 7:08 AM

I was told it probably just needed a top end. LOL. Oil looks like chocolate milk, the impeller housing was completely gummed up with what I guess would be rusted coolant, oil, dirt and something else. Both main crank bearings were shot. Crank needs to be rebuilt. Cylinder needs to be honed and replated. I sourced every gasket and every bearing for the rebuild of the motor.

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6/1/2018 7:10 AM
Edited Date/Time: 6/1/2018 7:15 AM

Right about now you're wondering why I bought this turd and just what I had to give up to get it. I paid $200 for this bike. I bought it because I remember the time I walked into a dealership in 88 or 89 and saw it sitting there. I was 13 years old and I was just blown away that it was an 80. At the time I was riding a 1980 Elsinore CR80, so this thing was huge and comparison.

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6/1/2018 7:19 AM

Nice work. I can understand your desire to build it. I have a few old bikes including 80s that are the cool memories of my youth. I like to get mine going and looking decent and ride them. We had a Race at Waldo Fl this spring that was for 80s 89 and older.

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6/3/2018 8:25 AM
Edited Date/Time: 6/3/2018 8:27 AM

Dude I am doing the exact same bike! it was my first race bike, I'm about a month out from sending my cylinder off to Millenium too. I've been trying to find a rear fender, dam near impossible.... Can't wait to see how yours comes out. I'm not going to the degree you are, but hoping it looks good.
How did you get plastic looking so clean? is it new plastic or you clean it up?

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"So you're telling me there's a chance!!"

6/3/2018 8:32 AM

That's awesome man. I never question anyone's reasoning for buying any bike and yours is looking great so far. It's hard to put a price on childhood memories. Keep us posted!

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Throwbackmxguy

6/6/2018 8:13 AM

rucka356 wrote:

Dude I am doing the exact same bike! it was my first race bike, I'm about a month out from sending my cylinder off to ...more

Hey rucka! Are you going to keep it 80cc or punch it out to 90? Plastics are insanely hard to find and crazy expensive. A new right side radiator shroud with graphic just popped up on eBay it's a 150 freaking dollars.
https://m.ebay.com/itm/Kawasaki-KX80-shroud-new-49089-5016/183248647596?epid=24013889894&hash=item2aaa7875ac:g:py8AAOSw8OpbDX~M

These are all the original OEM plastics. To get the old sun oxidation off of the plastics I used a razor blade at a 45 degree angle and scraped it off. I then use progressively finer wet sandpaper (600 to 2000 grit) to smooth it out. Then finally I hit it to very carefully with a heat gun to bring the deep olefins back to the surface. They don't have the luster or shine that new Plastics do but they look a hell of a lot better than they did.

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6/6/2018 9:02 AM

I'm keeping it 80cc. Just got my piston kit delivered yesterday. Got new wiseco kit for $65 on ebay, included everything but gaskets. I can't believe how good your plastics look.... I thought about stripping the bike down to frame to powder coat it, but want it to have a different kind of look. Will probably ride it occasionally and if it breaks down again i will hang it in my garage on wall or from ceiling with some of my trophies from racing it (Man cave). Let me know if you run across a rear fender. You still need any parts? I keep my eyes peeled, almost bought one off craigslist the other day just for parts, but they wanted way too much and wouldn't sell any parts off of it.

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"So you're telling me there's a chance!!"

6/6/2018 10:44 AM
Edited Date/Time: 6/6/2018 10:46 AM

rucka356 wrote:

I'm keeping it 80cc. Just got my piston kit delivered yesterday. Got new wiseco kit for $65 on ebay, included everything but ...more

I thought about powder coating the frame but I'm going for the Tow Mater "shoot, don't touch my dents" look. It's a 30 year old bike and I kind of want it to look that way but be mechanically sound.

I'm really leaning toward the 90cc kit. Unfortunately it damn near doubles the price of the motor build.

No problem. I'll keep an eye out for an 88-90 rear fender.

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6/10/2018 6:47 PM

Damn that brings back memories! I had a brand new 1989 KX80 big wheel.
Bought the 100cc kit from Kawasaki when bike was picked up from dealer. As far as I know, the original 80cc
cylinder/top end is still sitting in the boxes on a shelf in my Dad's shop.

Whereabouts in Texas did you find it? I'm still trying to locate my original bike.

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6/11/2018 1:23 PM

drvnfast wrote: Photo
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Looking really nice... I had an 89 KX 100, the BW was a 100 stock in the U.K, keep the posts coming.

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6/11/2018 4:22 PM

svt93cobra wrote:

Damn that brings back memories! I had a brand new 1989 KX80 big wheel.
Bought the 100cc kit from Kawasaki when bike was ...more

Very cool! I found it just outside of Austin.

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6/11/2018 4:40 PM

That's my area. Do you have a number I can contact you at?

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6/11/2018 8:42 PM

svt93cobra wrote:

That's my area. Do you have a number I can contact you at?

PM Sent

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8/24/2018 4:56 PM

Update.

I have the bottom end done and installed. Cylinder and Wiseco piston headed to MT next week. Photo

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9/1/2018 10:39 AM
Edited Date/Time: 9/1/2018 10:41 AM

Any chance you found a spare parts bike and have an extra clutch cover? I was finishing, just putting clutch cover on and it cracked..... May have just ruined my project!!

Looks like something is up with shift shaft, it's not letting cover close all the way...

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"So you're telling me there's a chance!!"

9/1/2018 10:41 AM

By the way, millenium did a great job on my cylinder!

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"So you're telling me there's a chance!!"

10/1/2018 2:23 PM
Edited Date/Time: 10/1/2018 2:35 PM

rucka356 wrote:

Any chance you found a spare parts bike and have an extra clutch cover? I was finishing, just putting clutch cover on and it ...more

Hi Rucka! You're not going to believe this but I did the same thing to my clutch cover. If the shift shaft is not completely seated (which is kind of tricky to tell) you will crack the bottom left of the clutch cover. I JB welded the crack inside and out then once cured I very carefully ground down the gasket surface flat. Good Luck.

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10/1/2018 2:34 PM

The right arrow is pointing toward the selector portion of the shift shaft which has a round "nub" on it. that sits within the forward part of the the pawl ( second arrow). If the nub is sitting upon (rather than within) the forward notch of the pawl then you will crack the cover. I found it helpful to put the shaft in then put the foot gear selector on the other side to hold the shaft in place while installing the pawl/spring etc. Photo

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