In Memory of Caleb Taiki Thomason

Part One

Welcome to PROJECT NSR 500. The latest project bike is owned by Chris T of Kentucky, USA. You may have seen Chris and his cool NSR 250 machine before on this Website. It was featured as February 2001 Bike of the Month. Chris shows us how to stuff a CR500 engine into a NSR 250 frame.
95K - Click for full size image This time Chris has come up with a very interesting idea. As you may know Chris has a very nice 1990 MC21 NSR 250R. He also has a CR500 dirt bike (actually two)............. than it happened !! Chris decided one day to make his very own NSR 500 by transplanting the engine from his 1993 CR500 into his 1990 NSR 250R.
The first thing was to remove the engine and other unnecessary parts. The NSR frame was thoroughly cleaned and degreased. One important part of this project was to not make any permanent modifications, all the original parts were cleaned up and packed away, no welding or hacking away either. His bike can be easily restored to a NSR 250 again if necessary. 83K - Click for full size
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Here it is, the CR 500 engine after a thorough washing. The engine is a liquid cooled single cylinder two stroke monster with a engine size of 491 cc. Horsepower is rated at 60 by Honda with 48.5 foot pounds of torque. Chris fabricated his own custom frame mount brackets to mount the engine with ease.

The engine getting ready to be lifted into the NSR 250 frame. Amazingly the CR 500 engine is lighter than the NSR 250 engine and Chris was able to lift the engine in place by himself.

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In this picture you can see the other bracket (blue colored ) that will bolt just behind the top of the cylinder head on the CR 500 engine. The aluminum pieces sitting on top of the blue bracket are for bolting the ignition coil close to the cylinder head.

Here is the engine frame before painting it. Made of metal, this frame was made by hanging the CR 500 engine in place and constructing the frame around it. It took about six hours and extreme patience to build it. Every little slight bend would throw everything off, so it was corrected and re-corrected numerous times. Chris had to be very careful due to the very tight clearances. 56K - Click for full size
54K - Click for full size image The top view of the engine frame after painting it. The frame bracket is designed so that the engine is slightly offset to the left for sprocket alignment. Though it is not easily seen in the picture, this was one of the many small things Chris did not overlook.
In this picture, the frame may appear slightly crooked or uneven. Though it may not sit perfectly flat on the ground, the bracket holds the CR 500 engine in place perfectly. 50K - Click for full size
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This picture shows the CR 500 engine just moments before the engine is rotated into position. The mount just behind the cylinder head is already joined to the top bracket. The rear mount was designed so that the original NSR engine bolt could be retained and slide right through NSR style.

That completes Part one of Project NSR 500. Part two will show you the complete engine installed, carburetor installed and the beginning of the very interesting expansion chamber for this special machine. Stay tuned for Part two..........coming soon !!

Part one - getting started
Part two - engine installation and exhaust
Part three - completion

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