atc250r, cr500 cylinder swap

[atc500x]

Someone ever try it? I talk with a guy near me yesterday on facebook who fit a cr500 cylinder on a 250r crankcase(he bring them to a machine shop who did it for 2500$.....................),the got 69hp and 70 lbs torque out of it.He kept the 250r crank and change the rod.It's not a 500cc since the stroke is shorter,but 69 hp is very nice,especially if you can keep a stock frame with foward kick start.I think I will try it this winter.....

[oscarmayer]

more details and pics!!!!

[C.J]

Not too similar but a buddy of mine is running an aftermarket Liger CR500 cylinder on his quadzilla bottom end. It's like a 680.

There was a dude on trx250r.net or .org or something like that that was making cases that kept the engine forward kick but used all the internal parts of the CR500 and it just bolted into ATC/TRX's.

[jeffatc250r]

I dont think the clutch, trans would hold up without serious upgrades. Although it would be nice to have the atc gearing and eliminate the rear kick issues, i think your gonna spend alot of time and money trying to get it right. Just my opinion. Cr500 motors are pretty much bulletproof and best bang for your bike IMO My only real complaint with mine is if you gear it so you can still drive in tight woods, you end up with a machine that has the top speed of an sx, go the other way and your constantly on the clutch.
I would like to find a lower gear ratio for first, that would be nice.

[Rex Racing]

way easier to just bolt on a 330cc cylinder, mine makes 55 horse at rear tires, port design on cr500 not that great either, would love to see what a cr500 makes on the same dyno.

[atc500x]

No too much detail about his setup,and not sure he know more too,the machine shop built it,and he don't know what rod they put in it.I think if I want to know what it look,I will have to build one.The cases and cylinder are on the table......

What I know is he used the 250 pipe and he have overheating problem,normal I think.....he told someone will built a custom pipe for it.69 hp with the wrong exhaust,imagine with the right one.....
True or false,he tell me he did 100 mph with 15-36 gearing.....

I really have to built one to try!!!!

[atc300r]

There used to be a website about a company that did this setup .But I cant find it. The 400 pilot cylinder is a popular setup for the 250r.

[Super350]

I dont think the clutch, trans would hold up without serious upgrades. Although it would be nice to have the atc gearing and eliminate the rear kick issues, i think your gonna spend alot of time and money trying to get it right. Just my opinion. Cr500 motors are pretty much bulletproof and best bang for your bike IMO My only real complaint with mine is if you gear it so you can still drive in tight woods, you end up with a machine that has the top speed of an sx, go the other way and your constantly on the clutch.
I would like to find a lower gear ratio for first, that would be nice.

Get the close ratio gearbox Hundo like mine!.....I thought you had one

[jeffatc250r]

Your bike just has a slower 5th gear ratio, rest is the same as mine.

[atc300r]

I think this is the article.http://www.atvsource.com/articles/pr...mac_racing.htm

[atc500x]

I saw this article,but I was curious to see the setup closely

[LastFoolerInVA]

reading that article... it actually sounds alot like what Billy was doing to the hybrid he was working on.

[Rex Racing]

No too much detail about his setup,and not sure he know more too,the machine shop built it,and he don't know what rod they put in it.I think if I want to know what it look,I will have to build one.The cases and cylinder are on the table......

What I know is he used the 250 pipe and he have overheating problem,normal I think.....he told someone will built a custom pipe for it.69 hp with the wrong exhaust,imagine with the right one.....
True or false,he tell me he did 100 mph with 15-36 gearing.....

I really have to built one to try!!!!

it could happen my trx330 with 15-38 gear and me 260lbs, on radar not no guessing 86mph, 3wheeler is lighter and a lighter rider

[Tecate250]

Hey Atc500x Do you know Tordeur4x4 "Eric" Great guy. Anyway I remember back in the day people used a jet ski piston for a over bore piston for a Tecate.

[Dirtcrasher]

I dont think the clutch, trans would hold up without serious upgrades. Although it would be nice to have the atc gearing and eliminate the rear kick issues, i think your gonna spend alot of time and money trying to get it right. Just my opinion. Cr500 motors are pretty much bulletproof and best bang for your bike IMO My only real complaint with mine is if you gear it so you can still drive in tight woods, you end up with a machine that has the top speed of an sx, go the other way and your constantly on the clutch.
I would like to find a lower gear ratio for first, that would be nice.

Jeff (Or anyone), how much fatter are the 500 gears. The gear shafts are the same OD??