XR80 to XR100 Conversion

After my recent CR80 / XR100 conversion project, I had quite a few leftovers from the XR100 which donated the engine. So I decided to convert my son's old XR80 to an XR100 using the parts. That way we will have a bike to take his friends riding without them being quite as cramped.

Here is the 2003 XR80 which will be upsized.


Here is what's left of the 2001 XR100 after the other conversion project.


I exchanged the front wheel between the bikes. I put a new tire on the XR100 rim. I was surprised to find that the XR80 and XR100 forks were not the same length. Here is a picture of a fork off of each bike.


Because of the longer forks, the front brake line is also longer on the XR100. Here is a picture of the two brake lines.


Here is the XR80 with the XR100 front end.


Tomorrow night I start on the back.

Very cool dr!!! :):)

Should of just stuck the xr80 engine into the xr100 chassis.... but that way will work too..

Are you selling any leftovers?

I want the 80 front end if you got it still. Or just the wheel maybe.

As for leftovers, let me see where I stand when I am done. I am sure that I will be getting rid of some of the stuff. I'll let you know...

I had to go get a new tube for the rear tire, so that slowed me down a bit.

Here are the two swingarms. The XR100 is on the bottom.


With that longer swingarm, the rear brake rod needs to be longer. Here are the two rods.


Surprisingly, the XR100 spring is slightly longer, but not the shock. The XR100 is on the right.


I chose to go with a 428 chain like the XR100 rather than the 420 chain like the XR80. That meant I needed a front sprocket from an XR100 for the XR80.

With the taller height, the kickstand is also longer.


Here is the finished bike. It's kind of a big wheel XR80.



Wow. You've built two custom conversions in the space of a couple months. I'm feeling a little unproductive... Nice work.

Hey, that looks like one of mine:



I just put the XR80 motor in the 100 roller along with the carb and air boot.

I have two XR80's with 120cc motors in them. The second one should be finished tomorrow with the trailbikes kit.

I have two XR80's with 120cc motors in them.

I bought some things for an engine upgrade, as well. I got an XR100 clutch center and a rebuild kit to convert it to an XR100 four disk clutch. I have the cylinder and piston left from the XR100 to upgrade the XR80 to a 100.

I noticed that the connecting rod is the same at the bottom, but smaller at the top for the XR80, so I bought an XR100 connecting rod. Is rebuilding the crank straightforward? I don't know if I will do the engine upgrade right away, but I'd like to know how much work is involved.

You can't use the 100 cylinder, but you could bore the 80 cylinder.

Good job!

My buddies want to transform a CR80 or 85 into a 200. 200 engine on a 80 or 85 frame.

Anyone done it already? :)


Yea it's been done alot check out www.socalxrs.com/dmc.htm or just do a search in this forum.

some of you guys are motivated . the bikes look great :)

some of you guys are motivated . the bikes look great :)

Yeah, and I have the motivation, just not the money...which sucks :)

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