A lightly modded stock 250R engine will pull 80+ MPH, so the guys project seems like a waste. Your easiest solution would be to get a 350 Powervalve jug on a 250R bottome end, see CT racing,LRD racing, etc, etc. These will be good for 60-75 HP depending on your pipe/carb/compression/ignition/etc. You can also go with a stroker crank for a motor up to 425cc The CR500 would flat out haul azz. You can turn the CR500 motor into a 100HP time bomb if you want. I see no problem getting a reliable 80hp with mods. One issue with the CR500 motor in a quad is vibration. If you look around on the web you will find tons of big bore mods for these motors. The 350 jug allows you to return the motor to the stock cylinder if desired. The price for the motor kits seems to be high up front, but would be NOTHING compared to the cash you'd have tied up with a street bike motor in one of these machines, and the streetbike motored machine would get it's azz whipped anywhere but on a paved drag strip, and probably even there as well.

The projects you are talking about would be a monumental waste of a good quad, time, and money unless you just have to have something unique, heavy, slow, expensive, unreliable, and un-saleable when you want to get rid of it. Not trying to flame anyone, just pointing out the facts as I see them.

 

KCIH, I couldn't have say it better myself.

 

i dont know where your getting unreliable and slow from...my 98 cbr600 (yes....only a 600) will go 105 in third gear (it has 6) and it reaches 125 very quick i can tell you that (its the fastest ive wanted to take it) and they are bulletproof...go ride one

 

Derekhonda,
Maybe you should read the thread before you reply. And hey, why don't you put the motor from your motorcycle in a quad and then tell me how fast it is after I'm done smoking your *** with a 350 single cylinder.

 

i was talkin to my bro tonight and he said he know a guy who blew up his blaster years ago so he just had a rolling frame for awhile, and another had a cr500 and doin big jumps (like telephone wire touchin, 4X4 truck clearin) and just destroyed the frame, so the guy wit the blaster frame bout the cr500 threw away the frame and modded the blaster to fit the cr500, so i guess him and his friend are gunna beef up the frame and put a wheelie bar on it, hopefully i can see it soon, that would be nuts!

 

There is some race shop I think in Jersey that builds these quads for you. They had a Zilla and a Banshee with 1000cc street bike motors and a 250r frame with a cbr600 engine in it and 400ex plastic they said it would do 150 mph+ but didn't list weight or any real specs. I guess you would have to call them or something. They have a web site but I didn't book mark it so you might have a tough time finding it. Actually SparkyEX found it so he might know the url.

 

I've seen a couple of these types of deals. One was a definite "home swap". A early 70's Honda 750 in a 250x, and the other was super nice looking, a 650 ninja motor in a quadsport 250. Both were way heavy, too much so for the suspensions on a quad. At a radar run the ninja motor was actually rather slow, not enough time/space/gearing to allow the motor to rev. The old 750 actually ripped pretty good, having more torque on the low end. Both machines were disapointingly slow. From what I've seen and heard, for trail and fun riding, a moderately punched up 250R motor is hard to beat.

 

check out aug atv action, or dirt rider, theres an article on a company that mods quads, the article is a 600exi. 400 ex plastic, 86 250r frame with an '02 cbr600. sweet looks totally stock, also states person who ordered it is using it for mx. i think the company is calo racing
yup here is a link....calo racing.com