Cr80 4stroke?

Rat_ranger

Coast to Coast
So I have my 79 XL75 and it has a built XR100 motor in it. 120cc, cam, HV oil pump with cooler, ported head, and while it's fun for how ridiculously over-powered it is, it just has terrible suspension. I still have the original motor, just needs a piston and bore, so it'll go back to original.

Now comes the 97 CR80 I picked up yesterday with no topend. It'll get the 120 motor swapped in to make a fun little trail bike with decent suspension. I've read up on doing the swap, so other than needing some 1" DOM and time I've got the tools.

Hopefully by the time it's done I'll have less than $600 added into the current money in the motor.
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Rat_ranger

Coast to Coast
Step 1. Pull whats left of the original motor. It was made easier by the 2 missing motor mount bolts, but the swingarm pivot bolt took some heat and hammering to get out.

Next step is tearing the bike all the way down, front end off, swingarm and shock off, subframe off.
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irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
I have a little XL100s. Would love to do something like this with that engine, or at least have legit suspension on that bike.
 

Rat_ranger

Coast to Coast
Yeah, the biggest downside the the little XR and XLs is the lack of suspension and the flexy frame. They really need a frame brace under the motor, and if you ride it "hard" the forks flex pretty bad.

I got lucky, I'd been watching the sale pages on FB and saw this cr about 15 minutes after it popped up. Snagged it for $75.
 

Hurco550

Keep er' Between the Ditches
DTT SUPPORTER
DTT BOTM WINNER
How much 1" DOM you need? I've got a couple sticks of .125" wall. I can cut a few chunks down and mail it to ya if it saves you buying a whole stick or having to pay lots for a custom cut.

Neat project
 

Rat_ranger

Coast to Coast
I got some coming already. I don't need big pieces for this, but I ordered 2 sticks because I can use it for some other projects. Thanks for the offer.

I'll finally make use of my tube bender again. I don't use it much, but nothing can take its place when I need it.
 

Rider52

Coast to Coast
One of my cousins made a business out of installing Honda 100-125 engines in 125/250 two stroke frames. You may have heard of him Guy Cooper.
 

Rat_ranger

Coast to Coast
I can't say I have. But most info I've found is on forums, so I might have read about him and not known.

Once I get the rear mount fabbed up and get the sub panel in the garage I might go overkill and do a billet rear mount. Nice thing about that is once I have it figured out it could be copied to help others with a similar swap. Still lots of fabbing, but motor location being set would make things easier.
 

Rat_ranger

Coast to Coast
Well while I wait for the DOM I decided to open up the rear shock. It felt like it had no damping, and that was because it had no fluid. So it's going to get cleaned real well and once parts get here will get new seals.

Forks are getting the same treatment, but those still have some fluid in them.
 

Rat_ranger

Coast to Coast
Well I'm starting by probably going overboard on accuracy for the tube that fits on the swingarm pivot that'll be the base of the rear upper mount.
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Rat_ranger

Coast to Coast
So down tube is tacked in place. Engine is roughly where it'll sit. Got some more measuring and level checking before commiting anything permanent.
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