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NSR50 > NSF100 conversion

8460 Views 24 Replies 7 Participants Last post by  Luckystar64
I am joining the dark side. A bone stock NSR50 is too long in the tooth to keep up with the 4s MiniGP bikes. Our spec class puts the NSR with the Honda NSF100 and Kayo GP 125.

My donor bikes are: 2004 Honda NSR50, 2002 Honda XR100

I have the bracket kit coming from Brian over at team quazzy moto
XR100 Motor Bracket Kit for NSR50
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Bumper Automotive exterior Auto part Vehicle Pipe

Tabs are cut. Sharp edges filed. And cracks in the bodywork mounts discovered. Gonna need to fix those for sure. A crash or two and they will finish up their journey to freedom from the frame.
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The Team Quazzymoto kit made this almost too easy. Rule 1 read all the instructions. :)

Then everything was cake. The installation was done in one hour.

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The bike is now running and almost done. A few things I didn't know to begin with.

Follow Brian's instructions and the only mods you need to do are removed of a couple little brackets around the motor.

The XR stock throttle and clutch cables work great. Don't use the NSR stuff just carry the XR stuff over. All good.

I was lucky and able to find a pipe that had already been used on a NSR XR conversion. So the fit was already done. I just had to hose clamp and safety wire some stuff.

Make ke sure to heat wrap all of the exhaust. If possible the can too. The heat is going to melt the underside of the NSR bodywork. Or on the can put a heat shield on the underside of the NSR tail. I had to bend the center crossbrace of the subframe to ensure the can didn't hit the tire when the read was loaded up.

The XR kickstart won't clear the footage and brake. Need to find another with a shorter arm. Or one that the arm kicks out wider.

All told old this was a super easy conversion.
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short video of the bike running
And. The countershaft sprocket is different. Of course it is. Just forgot to order a new 420 sized sprocket.
Last bit of information I needed to wrap the project (from fireman Brian). The NSR front sprocket bolts right up to the XR motor.

The XR is a 428. The NSR is a 420. So just put the NSR sprocket on the XR motor and all done. :)
Bike is done. Conversion complete.

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Thanks man. It's been great.

I ran into some teething issues. The exhaust is rubbing the tire. So need to raise it 1.5 inches above the subframe height. And the stock throttle throw is way too long. Need a quick turn as the XR throw requires a serious twist.
After having a warm butt I decided to put a barrier between the exhaust and me. Also finished up the gas tank venting. And crank case catch bottle. All ready for the September race.

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And a shot of the elevated exhaust. Just bent the rear end of the subframe vertical.

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This project is done. Just ran a shakedown and all was good. Next race is two weeks out.

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It went really well. It was a nice change to be running in the top three instead of the back three. The kayos have extra pull, but overall it was well worth the effort. All in all very happy.
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