can u bore a 250r to a 315 or wat is the most?

is it a stock cylinder...if it is i dont think it can be bored very big at all...my buddy has one thats bored and its like a 265...but i think he can bore it more but not sure how much...you should just buy the sabertooth cylinder...lol..you should chech it out its a 500..its insane...

or go puma

265 is about as big as your going to go on a stock Jug. You can get different kits through most engine builders, I know Sparks and CT always built some kickass 250R engines. I had a 265 Sparks and that thing was nasty. You can bolt on a 310 with out having to have your cases machined. But if you go with a 330 and up you need to have your cases machined out. I will say, that I got the chance to take Nic Grandlunds CT 370 for a spin and that thing was just insane... way too much power for me to ever want on a MX track.

send your motor to packard if your looking for big hp numbers

you can resleeve and get out to 295. Or you can bolt this on for 272cc and proven 57hp

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...em=180340169257

There are a ton of big bore options....if you want more than just the normal +0.25m sizes....

you can go up to about 295/310cc (depending on company) with just bore size on their cylinders with no case machining... above that... you need to machine the cases.....

some companies even offer a complete Nikasil cylinder...unlike the typical and stock iron sleeved type... a bit more money... but then again....your getting a better cylinder.....

good thing about the aftermarket cylinders is that they all come pre-ported.....usually with your option of type... MX/trail vs drag race, etc....and they also 'usually' come with some type if interchangeable head dome system..... very nice setups for a reasonable price.....



ESR/Duncan/CT, etc...all fine 250r companies.


jmho....Greg

Greg pretty much sums it up. With a stroker kit, machining the case halves and using the Pro-X or Honda FL400 Pilot cylinder you can get it up to 410cc. The largest bore on the stock cylinder is 265cc. Don't buy the BS marketing of the "310" kits as they are actually only 295cc. Anything over 295cc's without a stroker will require you to machine the engine cases to fit a larger sleeve as well as go with an aftermarket cylinder.

If you want a sweet setup, shoot for a non-stroker 350cc kit with a powervalved aftermarket cylinder. Save yourself some heartache and replace your 2nd gear in the transmission while the cases are apart. It's around $100 and it's always the first thing to give with the big power builds. Also get a 38-39mm flat slide carb to go with it and a good reed cage setup.

Cool heads are good insurance for a big cc build as well. Good luck!

Jared

eddie sanders racing makes a 330 bolt on thats what i run on mine as long as you have a long rod crank (i believe its 87 and up that come stock with it but could be off by a year) but with the 330 bolt on you lose a bore on the cylinder but they make the same power i havent got mine on a dyno yet im getting a port first but they scream when you get the jetting dialed in

I have a 86 motor on a 88/89 frame. Stock cylinder on a 86/87 can be bored 69mm, making it
a 269cc. The long rod's are on the 88/89 motors. ESR has good stuff for the money.

actually......86 was the only year for this setup.....

all years have the exact same stroke... but the 87-89 machines had what is called a LONG rod.... some even call it a stroker.. but again....it aint... just a longer rod which utilizes a different piston (wrist pin placement).. you can put an 87-89 crank in an 86 engine...so long as you use the correct piston with the crank.... it wont gain much unless the cylinder was designed for this setup...... most companies build their HIGH HP machines around the 'long rod' setup and therefor it is beneficial.....

the bore and stroke for all trx250r's was 66mm bore X 72mm stroke.... just as a reference.... an 06/newer 450R has a 96mm bore and only 62.1 stroke.....

basically.....the two stroke has an over-stroke setup... while the four bangers are an over-bore setup.... kinda funny when you realize how those 250r's rev up.....

DeadEye was purdy accurate.....a nice bored carb 38/39 along with 350+ cc machine, interchangeable dome head, good porting and pipe.....and these machines will absolutely rip.... 370-410 kits are not considered reliable machines.... drag race only..... as for power valve cylinders..... a nice option..... doesnt really make more power.... but makes more 'usable' power for those who use the lower/mid portion of the power band..... a bit pricey tho....

my biggest issue...is finding the right set pf paddles.......my lower HP 250r needs a LOT more paddle then my nitrous fed 450r..... go figure.....lol


jmho....Greg