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Discussion Starter · #1 ·
I will tell the story later, but here is a 1985 Kawasaki KX80 with a Honda XR100 engine. Built by John Cartwright of Cartwright’s Conversions back in 1992. I’m going to fix her up…


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1970 CT70, 2019 Super Cub 125, and five or six other basket cases
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Yesssss I love weird swaps. Also that swinger looks CHONKY in the pics. Keep us posted.
 

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Discussion Starter · #5 ·
Bike has been sitting for probably 15 years, maybe more. I don’t think the shock or forks have a drop of oil left in them. So those are getting a rebuild. Here are a few shots of the bike with less plastic…

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Discussion Starter · #6 ·
Shocks off to get re-built, re-valved and sprung. I’m going to pull the forks apart and get them re-built. Might go with some race tech emulators and springs for my weight. Got all new bushings and bearings for the chassis. Tires, tubes, rim strips. Chain and sprockets. Front brake is getting a full overhaul as well.

On to the fun surprise! Pulling the valve cover and finding this is one of the early roller cam mods John Cartwright did before Al Gore had the internet and e-commerce really going😜 Back in ‘91/‘92 Takegawa did not offer roller cams. This is a small custom product run done by John for a few of the early conversions. I really love this custom stuff! Speaking with John he can’t remember all the details, but assumes this is a high compression 120 with his custom roller head (rockers are not roller in this one).

Heck, this thing might be pushing double digits 😆

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1970 CT70, 2019 Super Cub 125, and five or six other basket cases
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LOVE stuff like that. Makes the days of hot rodded flatheads seem like not-so ancient history. We're gonna need some sound bytes when you're done. You're gonna make up an alternate "KXR100" lettered seat for this based on that box too, right? ;)

Edit: The more I look the more I dig the atmosphere of these pics. That's one trick stand you've got the bike resting on!
 

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Discussion Starter · #8 ·
LOVE stuff like that. Makes the days of hot rodded flatheads seem like not-so ancient history. We're gonna need some sound bytes when you're done. You're gonna make up an alternate "KXR100" lettered seat for this based on that box too, right? ;)

Edit: The more I look the more I dig the atmosphere of these pics. That's one trick stand you've got the bike resting on!
🤔 That’s a great idea …KXR! I have the 1984 SR125 Ward rode in my mind too.

Amen, love hot rodding! I got an old flathead mill that hopefully will make it into a rod someday soon.

🔈🔈✊✊
 

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Discussion Starter · #9 ·
Pulled the head today - here are a few more pictures of the one-off roller cam setup. Also, I confirmed that the stroke is stock at 45mm and bore is 57.9mm so my math says it 118cc. I assume this an old Takegawa big bore, maybe Powroll?

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1970 CT70, 2019 Super Cub 125, and five or six other basket cases
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Damn. I need to get some line boring tools. Is that plug there stock or is that an artifact of machining out the bearing journal? And does that little bump on the closest journal feed oil Into the ball bearing on that side?!
 

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Discussion Starter · #11 ·
Damn. I need to get some line boring tools. Is that plug there stock or is that an artifact of machining out the bearing journal? And does that little bump on the closest journal feed oil Into the ball bearing on that side?!
The plug is not stock, it was required after the stock cam journals were hogged out. The roll pin you see may serve dual purposes, but is absolutely there to stop lateral movement of the cam. Might serve up some oil will look closer. It’s a trick setup. I was hanging around John’s shop at the time he was building these bike, he was always doing cool stuff!
 

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Discussion Starter · #13 ·
So, it’s a Powroll 58mm (ART) piston. Damn sleeve was very snug in the cases!! Cases were fly cut to fit, but like pulling a stuck bearing. Lots of heat and some dead blow persuasion…

assuming I can still source rings since ART is a standard industry piston. Maybe a 500/4 Honda? Shout if ya can help. Talking with google now.
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Had a quick google for ya
It seems you might be in luck finding a piston
Can’t be 100% sure if this is the right one


also found this

 

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Discussion Starter · #15 ·
Had a quick google for ya
It seems you might be in luck finding a piston
Can’t be 100% sure if this is the right one


also found this

Thank you.
The piston is in good shape and was also carefully “clayed” and releaved for valve clearance, so I’m going to keep it. Digging around for rings. I saw a Honda CBR125r piston and rings. Maybe I can just get rings somewhere and hopefully they fit🤞
Like this
 

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1970 CT70, 2019 Super Cub 125, and five or six other basket cases
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if you’re comfortable adjusting end gap you could totally just get blanks for ~the right size bore.
 

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Discussion Starter · #17 ·
if you’re comfortable adjusting end gap you could totally just get blanks for ~the right size bore.
Got no issues with that. Any recommendations for where to source?

Again, this is an ART piston. My best digging found that the Honda CBR125 has a 58mm bore and there are rings available. Found these…

 
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