bored and stroked 500r?

[hondadozer3851]

Hey guys I was wondering if anyone has ever put a bored and stroked cr or kx 500 motor in a three wheeler

[yamaha driver]

i know people put regular cr 500 engines in 250rs before

[Tri-Z 250]

The thought of too much is just enough comes to mind. You only need to drop the front wheel when cornering anywayz.

[TecateDan]

I've seen severl 500's and had a KX500 motor sitting in a 1985 tecate frame on my shop bench. Somone on her has a noce atc500r called orange crush

[hondadozer3851]

Yea a 500 is already a handful on its own but there's gotta be someone out there that has done it I had a 87 zilla bored. 50 over port & polish full pipe and boysen reeds and that was wicked fast but after a couple weeks of riding it I wanted more power same with Every bike I've owned

[Afrothunderkat]

Thats a quad. Whole different ball game. Trikes take a little more gusto to operate than quads. Zilla engines are also not nearly as strong as a newer CR or KX 500 engine.


50hp 310 kit is enough in a trike unless you ride in the sand.

[RIDE-RED 250r]

Thats a quad. Whole different ball game. Trikes take a little more gusto to operate than quads. Zilla engines are also not nearly as strong as a newer CR or KX 500 engine.50hp 310 kit is enough in a trike unless you ride in the sand.

Not only that, but a well built 310 can make as much or more HP as a stock Zilla motor.. let alone the 330, 350 and so on...

Zilla motors didn't make a whole lot of HP for being a 500.....


To the OP: I haven't come across a whole lot in the way of big bore and stroker setups for the CR500 engine. CPI offers a CR500 big bore that boosts displacement up to 583cc... http://www.cpindinc.com/pub/manufacturer_list IMHO, you would be better off going with a quality and well built/set up/tuned 250r based big bore. I know of a good builder who is getting some SERIOUS HP out of CPI's Sphynx cylinders for the 250r. Pro-x, ESR and others just don't come close. My goal is to upgrade my stup to a Sphynx 78mm bore and a +4 crank in a couple years. That setup should be more than capable of running right on the heels of a CR500 powered R if not more.

[TecateDan]

FYI I know of a company that will build a 127 HP kx500

[RIDE-RED 250r]

FYI I know of a company that will build a 127 HP kx500

Saweet!!! :drool:


Yeah, you would have to be looking at a Saber to run with that!!

[TecateDan]

saber ? I don't know what that is

[hondadozer3851]

I wasn't really comparing the the zilla to the 500 dirt bikes I've ridden a cr 500 and its a wicked bike I guess wat I meant was the thrill of the ride I'm sure there is someone out there that has ridden it after a while and has gotten bored with the 500 motor and wants more out of it maybe its just me haha

[RIDE-RED 250r]

saber ? I don't know what that is

CPI's largest 250r big bore, the Sabertooth. They offer 3 total. Smallest being the Sphynx, next larger is the Puma (runs a CR500 reedcage) and the largest is the Sabertooth. The Saber setups top out at over 500cc but require LOTS of $$$ into the build so it holds together. CHeck out the link to CPI I posted above. You'll see what I mean.. BTW, I have no association to CPI. Just posting the link to show who is building the best/most powerful big bores for the 250r.

Personally, if I wanted CR500 power or more, I would build either a CPI Sphynx 363 or a 431 Puma. BDT Motorsports got 80 RWHP out of a 363 Sphynx without going to alcohol. That's already well beyond the output of the average CR500. ANd the nice thing is you still have a counterbalanced engine. Just make sure the transmission is up to snuff. I'm told a lock-out clutch is not necessary with the Sphynx cylinders. But once you get up into the Puma a lock-out clutch is necessary if you want the tranny to hold together.....

I was already quoted $1700-$2000 for a ported and flow tested, set up, and ready to run Sphynx 78mm bore, stock stroke (344cc) cylinder/piston kit. I would be willing to bet a quality CR500 powered 250r build could easily cost that much, or more, without going a big bore and stroker crank.....

Don't anyone get me wrong, I have nothing against ATC/TRX500r builds. Just want to get word out that there are other options out there where you can get as much to way more power from a quality big bore than dropping in the CR engine and dealing with the usual issues associated with it.

Main issue being the vibration... I do remember seeing a thread here a while back from a member in Australia who customized his 500 engine with his own custom built counterbalancer. He posted some vids he took throughout the process. VERY impressive I must say!