How to Build a CR/XR Conversion
by Jerry Matta
I've gotten so many E-mails about how to build a Conversion, I don't know why I've waited this long to write it all down. So here it is once and for all.
1. Buy a new or used XR100. If you're going to buy a used one, try to get a 92' or newer, because it has electronic ignition; otherwise, you'll end up paying about $150-$200 for one off ebay. Take the motor out and if the frame is in good shape, you can sell it or build another stocker.
2. Buy a new or used CR80 Big Wheel. If you're going to buy a used one, get a 96' or newer. There are some steering ratio differences between the 98's and later models, so you might want to try one first. Wash it as best you can, yank the motor out and wash it some more. That way, you can get more money when you sell it. You should be able to get $500-$1400 for the motor. Obviously, depending on how new it is, the more money you'll get. I got $700 for my 97' motor and I only paid $1500 for the whole bike.
3. Now that you have a CR and an XR, now what? Well, for about $3300 BBR Will build you a beautiful aluminum frame conversion or DMC will build a steel Factory Honda Looking conversion for about $1650. For DMC you will need to mail your carb (it needs a special extension) and airbox. This might also be a good time to drill your oil cooler, so mail your clutch cover as well.
4. After you're frame is shipped back and you put everything back together, you start it and it runs like crap, that's because there's too much air from the big airbox. Well, you can rejet it and get a different needle or build the motor. Build the Motor!
5. I would go for the no frills way to build it. Get a kit. There are plenty of big bore kits out there and here are a about the top three.
Kitaco 145cc kit. Best kit money can buy, period.
Takegawa 115cc kit with superhead. Great kit except for that dang offset intake.
BBR 120cc kit. I've heard nothing but great things about this kit.
Other motor needs
200x carb or 26mm Mikuni.
XR400 Oil Cooler -- you got to have one. Probably you should pay someone to do it. $85-$150
That's all you need. Other options like porting (which is good if the person doing it knows what their doing), but if not -- it's not worth it.
6. Ok, Now I have a complete bike, the motor rips, but the suspension is like Jell-O. Have no fear or less fear, because Lowe Racing make fork springs and shock springs. I use a 38 in the front and a 5.6 in the rear, ( I'm only 150lbs.) I talked to Dennis Briggs of XRBoyz and he says whatever you use on a 125 is a good starting point. After you get you springs, send your suspension off to get valved. I'm not sure if Lowes racing is still around, but Jason at Fineline Suspension can hook you up with custom springs. If you mention Socal XR's, you might be able to get a 10% discount.
7. Now, throw on some graphics and bars and you're ready to ride.
After all this you might be wondering how fast are these little bikes . . . It just depends on you. Me, I'm slow, but I've seen fast guys beat 450's all the time.