250R big bore or stock cylinder?

[garrettagr]

I have got a lot of help here with the splitting cases questions so i thought that i would pick your brains about the barrel dilema. The whole reason for this is that i want to get some more getty up out of my motor. I could go with a mild ported ESR pro x cylinder or i could just have my old cylinder ported and bored to a 270 or resleaved to a 295. I already have a cool head so i probably will have to get a new dome. What is your take on this, new cylinder or port and bore the old one?

[nitrousbaby]

the most power is gonna be from a esr powervalve kit but resleved to a 295 is also a good jump in power I ve got one and love the grunt it has

[RichM1983]

310 econo port from ESR then send it to flowtek for a nice quality porting job.

[ky 2stroker]

it kinda also depends on how much $$$ you want to spend on your engine for power. yea the ESR big bore cylinder kits are nice, but at close to $1000 for a ported 310 or 330 kit that is quite a bit of money. but there are other ways to get some good power without just thinking big bore.

my 260cc R runs easy with piped banshees in a 300ft drag, and usually wins if everything goes good for me. my mods are in my sig. so that kinda shows you that engine cc size doesnt really tell you much about the power that it puts out. but dont get me wrong, im sure a esr ported 310 or 330 kit would stomp my bike any day, but you gotta consider all the other componets like exhaust, intake, carb, and ignition for making good power too and not just going by bore size.

[nitrousbaby]

Originally Posted by ky 2stroker

it kinda also depends on how much $$$ you want to spend on your engine for power. yea the ESR big bore cylinder kits are nice, but at close to $1000 for a ported 310 or 330 kit that is quite a bit of money. but there are other ways to get some good power without just thinking big bore.

my 260cc R runs easy with piped banshees in a 300ft drag, and usually wins if everything goes good for me. my mods are in my sig. so that kinda shows you that engine cc size doesnt really tell you much about the power that it puts out. but dont get me wrong, im sure a esr ported 310 or 330 kit would stomp my bike any day, but you gotta consider all the other componets like exhaust, intake, carb, and ignition for making good power too and not just going by bore size.

well stated you can have a 330 kit but without the right carb exhaust and porting you gonna eat sand from smaller cc well equiped machines

[joe22883]

Quick question anyone know how much you can out of a longer rod? I am doing my first top end on my 250r and found out somebody put a longer rod set up im assuming an 87 and up crank and rod not sure though. I bought a spacer plate and went with the 86 piston originally the put in a shorter piston instead of getting the spacer plate.

[garrettagr]

Yeah, you will always have people on either side of the fence when it comes to big bores or not. Here is a question NitrousBaby. Does that 295 eat up head gaskets like many people say? I think i am going to opt for maybe a 270 on the stock sleave and get a new pipe carb ect. Right now the bike has an FMF, 36mm carb, stock reeds and so on. I think that any bit of improvement will be a big jump in performance. But i might do the 395 if the price is right and it doesnt eat gaskets or overheat. But trinity and LRD gave me about 800-900 dolalr quote to do this so i wouild just buy an ESR 310 for 100 more if i was going to do that. But nitrous baby, let me know how reliable your 295r is. thanks

[nitrousbaby]

when I first changed to the 295 I went through 2 head gaskets in the first 10 hours of ride time after that I installed a copper plated gasket and have had that one for two years now. And the 295 does produce more heat so I have installed a finn tube in the radiator line and a after market radiator. to get rid of the excess heat. Now my r is as reliable as stock but also get the tephlone coated piston have had great luck with that. I think the reason the head gaskets blow is most people dont get the head work right when you do the 295 kit.

[fiveOnick]

Originally Posted by ky 2stroker

dont get me wrong, im sure a esr ported 310 or 330 kit would stomp my bike any day, but you gotta consider all the other componets like exhaust, intake, carb, and ignition for making good power too and not just going by bore size.

I wouldnt call a bike or maybe two a stomping. Thats about all a similarly setup 310 from ESR would pull on yours. Its not much difference, but there is a lot more potential in the big motor.

[ky 2stroker]

Originally Posted by fiveOnick

I wouldnt call a bike or maybe two a stomping. Thats about all a similarly setup 310 from ESR would pull on yours. Its not much difference, but there is a lot more potential in the big motor.

dang are you serious? I figured that most of the big bore cylinders would out do the smaller bore stock cylinders, even when setup the right way. in what ways would they have more potential? would they just make more torque and stuff or would the hp numbers be much higher with similar setups.

so far, most of the 250r's that ive seen have had like lrd exhausts and big bore cylinders, but ive never actually seen one run in person., i'd really like to ride another modded out R and see how it compares with mine. but anyways, as soon as I get my cases split and replace the crank bearings and seals and put new rings on the piston im really gonna start looking into the cr ignition and start looking on ebay for parts. but I dont hardly ever see any 2001 cr 250 ignition stuff.