NEED HELP!!! 250r Big Bore Motor

[jk250r]

This is my first 250r and i am not really sure how to go about this??? I have an 86 motor with a 300 pro-x niks cylinder with coolhead that i just bought for 500 BUCKS (good deal)!!This cylinder is on its fresh third bore and was just honed!! I am going to use this motor with my ground up 250r winter build. Once the cylinder is on its last bore what is the best thing to do then?? If u resleeve a cylinder how much does it cost?? Also once resleeved, does that take the cylinder back to its first bore?? Is it better to buy a new cylinder rather than resleeving it or is it better to just upgrade to a 330!!! Somebody please help me and please be sure to try to touch all bases when explaining because i do not know to much about a 250r???

thanks, josh

[Rich250RRacer]

I don't know about anybody else, but I stay away from sleeved cylinders. They seem to run hotter and go through rings faster than an unsleeved cylinder. This could be caused by by a portion
of the original sleeve that stays intact and is bored to accept the new sleeve. With this, I don't think the cylinder can disipate heat properly. If you can get a sleeve to replace the entire original, then this problem may be eliminated.

[beak7707]

Yes you will have to have the cylinder resleeved. It will then be back to the first bore of whatever size sleeve you put it in. I would say that is like a 290-295 sleeve stock and it is now bored up to a 300. So if you had it resleeved it would be back to a 290 and after you kept boring it it would probably go up to a 305 or so then ou start over again. I'm not sure on price it depends on who you have do it because the new sleeve will have to be ported to match the cylinder. I have heard good think about the 300 resleeve, thats what balance ran on XC r and he had very good luck with it.

[throwinitup]

you better put a seat belt on that thing if you plan on makin it a 330. my buddy has a all-baldwin built 330r. he went to mark and said "money isnt a issue" and he ended up with one sicccc bike...its so fast..... :devil: