need some advice

[undergroundart]

so. before I do something dumb I m thinking that I should ask for some advice on here about building my boy a quad. this will be for flat track racing. what im thinking is a blaster frame, dirt bike engine, go kart rear tires. my main concern is an engine. I don't know much about dirt bike motors, what would be something good to start with? is there a big difference between an 80 and an 85? as builds go this is gonna be an average priced build.

[undergroundart]

looks like I can get a complete older dirt bike for about the price of just a single newer engine on ebay. is there a big power difference between an older engine and a newer one? I m leaning towards a Honda, I think parts and finding someone around here to help work on it would be easier with a Honda.

[bigdaddy77]

I would scrap the cart tire idea. We are in the process of gathering parts for the same build. I was hoping to have Jeff Roberts build our a arms and swingarm but he is pretty back logged. What he told me was the cart tires were big before they started making a smaller flat track tire. Now you can get several brands in the 15" tire. We still run cart tires on our Xtreme but run them on all 4 wheels. As far as motors we run CR motors in our MX quads . They are 85 cylinders with the bottom end stroked making them 90cc. You can probably get by for a while running a stock cc motor. The bottom end on these motors are the same from like 1996 to 2007. In I believe 2005 they changed the way the pipe came off the cylinder, also 2007 motors have the best electronics and stator. So if you can find a older bottom end you can put a 85cc cylinder on it. The problem is these bottom ends start to get a lot of wear on them. Last but not least the most important part is DO NOT CUT THE PIPE TO MAKE IT FIT !!!!
Look on the Blaster part of the forum there is pictures of a few that have been done. Seems the YZ motor fits in them pretty sweet too.

[bigdaddy77]

I would scrap the cart tire idea. We are in the process of gathering parts for the same build. I was hoping to have Jeff Roberts build our a arms and swingarm but he is pretty back logged. What he told me was the cart tires were big before they started making a smaller flat track tire. Now you can get several brands in the 15" tire. We still run cart tires on our Xtreme but run them on all 4 wheels. As far as motors we run CR motors in our MX quads . They are 85 cylinders with the bottom end stroked making them 90cc. You can probably get by for a while running a stock cc motor. The bottom end on these motors are the same from like 1996 to 2007. In I believe 2005 they changed the way the pipe came off the cylinder, also 2007 motors have the best electronics and stator. So if you can find a older bottom end you can put a 85cc cylinder on it. The problem is these bottom ends start to get a lot of wear on them. Last but not least the most important part is DO NOT CUT THE PIPE TO MAKE IT FIT !!!!
Look on the Blaster part of the forum there is pictures of a few that have been done. Seems the YZ motor fits in them pretty sweet too.

[Logan #34's Dad]

1st, the Honda CR85's that are '04 and under do have a different gear ratio that the '05's and newer.
I will be selling two BADA** Honda motors here real soon.. One is an '07 Baldwin ported and stroked 90cc. The other will be an '07 Baldwin ported and stroked 101cc(supermini).
Undergroundart...if you can find the right TT circles...they will know where you can find a quad already done... Look up Mr. Haggerty and 404's Dad...

[undergroundart]

my blaster mod is coming coming together pretty good. im not sure if I should use the cr80 radiator or upgrade to something bigger? its the original radiator so it must be ok for the engine right?

[Logan #34's Dad]

Find one on eBay for a CanAm DS450. It's skinnier and taller than some of the others... I don't know what you have room for but, If you can put in the larger radiator...I would.