Yamaha MX 500 Prototype

[Lewis]

I've been offered a Yamaha MX500 that the seller claims is a prototype and one of 15 ever built. It's a complete runner that was raced and put away in a shed for quite a few years. I've trawled thru the internet but all I can find is the SC500 model. Anyone out there shed any light as to the authenticity of this bike. Search using the engine number comes up zero on any Yamaha site,not one bit of information other than peoples opinions on it. So did they actually make 15 of these and how are they identified? Seller certainly appears to be  knowledgeable and says all they right things but I just can get any info anywhere. Ok Yamaha experts what's the general thoughts on this bike.True or BS? If it is genuine any ideas of value? Need a total rebuild as it's complete but rough.

[mick25]

I went on Goggle images and typed in mx500 prototype
and two bikes showed up , they didn't look like SC500 bikes diffrent tank.
I'm not sure if they are the real deal on goggle images.
I found some info on the net 13 were made three came to australia but only two left in australia that they know of .

[gt96]

http://www.vintagemx.net/1975-yamaha-mx500-prototype/

http://dropbears.com/gallery/yamaha/Yamaha_1973c_MX500_SC500.htm

[80-85 husky]

ol mate mr fixit (MacGyver) has an sc 500 for sale as well. they are thick on the ground

[motormouse]

http://forum.ozvmx.com/index.php?topic=25620.0

Not this one again?

[sleepy]

I've been offered a Yamaha MX500 that the seller claims is a prototype and one of 15 ever built. It's a complete runner that was raced and put away in a shed for quite a few years. I've trawled thru the internet but all I can find is the SC500 model. Anyone out there shed any light as to the authenticity of this bike. Search using the engine number comes up zero on any Yamaha site,not one bit of information other than peoples opinions on it. So did they actually make 15 of these and how are they identified? Seller certainly appears to be  knowledgeable and says all they right things but I just can get any info anywhere. Ok Yamaha experts what's the general thoughts on this bike.True or BS? If it is genuine any ideas of value? Need a total rebuild as it's complete but rough.

What is the engine number?
Any photos?
There is this photo on the net.  http://i177.photobucket.com/albums/w235/f1ed/1973YamahaMX500.jpg
Looks like an SC500 to me.

[Lewis]

Thanks everyone. That's all I need to know. Best to leave it in their shed.

[Iain Cameron]

Not this thing again .

[Rossvickicampbell]

the prototypes/works bikes didn't come with engine numbers did they???  IT may even be a SC500 in a YZB frame - popular hybrid in the West.

[Iain Cameron]

No Ross this franken bike shows up every few years , the owner spins the same bull each time  (prototype only 13 / 14 /15 made )
Its a 1975 MX250 frame 509 with a DT400c motor . Yes the prototypes had frame and engine numbers . usually OW but some of the early works used YZm .