XR80 to XR100 Conversion

14 replies to this topic
  • dr_drz

Posted June 28, 2005 - 06:51 PM


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.
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Here is what's left of the 2001 XR100 after the other conversion project.
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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.
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Because of the longer forks, the front brake line is also longer on the XR100. Here is a picture of the two brake lines.
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Here is the XR80 with the XR100 front end.
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Tomorrow night I start on the back.

  • ToaDsiX

Posted June 28, 2005 - 08:32 PM


Very cool dr!!! :) :)

  • 150stocker

Posted June 28, 2005 - 09:20 PM


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

  • socalxr

Posted June 28, 2005 - 09:35 PM


Are you selling any leftovers?

  • Youngr51

Posted June 29, 2005 - 05:15 AM


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

  • dr_drz

Posted June 29, 2005 - 06:25 AM


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...

  • dr_drz

Posted June 30, 2005 - 06:25 PM


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.
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With that longer swingarm, the rear brake rod needs to be longer. Here are the two rods.
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Surprisingly, the XR100 spring is slightly longer, but not the shock. The XR100 is on the right.
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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.
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Here is the finished bike. It's kind of a big wheel XR80.
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  • minioutlaw

Posted June 30, 2005 - 08:20 PM


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

  • socalxr

Posted June 30, 2005 - 10:33 PM


Hey, that looks like one of mine:
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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.

  • dr_drz

Posted July 01, 2005 - 08:07 AM


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.

  • socalxr

Posted July 01, 2005 - 09:51 AM


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


Posted July 01, 2005 - 10:01 AM


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? :)


  • 150stocker

Posted July 01, 2005 - 10:28 AM


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

  • xrbrp

Posted July 01, 2005 - 11:04 AM


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

  • foxmotox321

Posted July 02, 2005 - 06:11 AM


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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