what to do to the motor?

[DEERCHOOPER]

im still building my 86 250r from the ground up, its going to be a while before its on the trail. but im coming to the point where i get into the motor.

i know im replacing all the bearing and seal inside the motor. i have it torn down now, getting a new crank as well.

now the tough part. what do i do for a top end? thinking of one of the esr kits. but what size? i just dont want to put all kinds of money into it then find out i want more after its running. i would like to do it one time and be smiling, lol. im a bigger dude so more is better.

i do xc, ft/tt and little trail riding.

[rustyATV]

Make sure you use the main bearings with the 8 balls (88-89) inside instead of 7 (86-87). The "8-ball" bearings are the same as the CR500 mains.

Those riding conditions require polar opposite motors.

An XC motor is usually smooth with a lot of low end power.

An all around trail motor allows more midrange.

TT and flat track are usually hard hitting and have a lot of top end power.

What do you do the most? A TT style motor would be miserable for XC or trail riding, but an XC motor could be a slug on TT.

[DEERCHOOPER]

lets just start with the bore for now. all those riding conditions require port and polish.

everyone said the same thing with my 450r build. you cant have a motor do it all, i got it. i know im working on a 2 stroke now and things are different, but ill try to find a happy meadin.


8 ball bearings, check.

[woodsracer144]

i personally havnt rode on a esr motor that left me with a wow factor at all.. call up arlen at led and have him hook you up.. or ct. also are you looking for a stock cylinder or an aftermarket one...

[DEERCHOOPER]

i have 2 stock cylinders close to max bore.

[woodsracer144]

so are you going to a niks-pro x set up ported by some one or what were you thinking?

[DEERCHOOPER]

im looking for everyone else's idea of which cc motor to go with. then the work of which porting to get

[rustyATV]

I'm thinking a 310cc powervalve cylinder would be good. Not too big that you need aftermarket gears (someone correct me if I'm wrong), but big enough to give some grunt down low, and wider power spread to cover the different types of racing. Get an MX/XC port job and swap pipes to suit the racing you want to do.

[woodsracer144]

Yeah a 310 sounds good of or not and stock or aftermarket cylinder any way... I have a lrd 310 resleeved kit and it rips and I don't have it even jetted 100% perfectly

[Honda 250r 001]

i got a Pro x310 blank, no porting on my Short rod 250r. In a drag race against a 450, its neck and neck. I also have the other essentials, such as carb, reeds, timing, compression, and pipe. But i am almost sure you would be happy with a 310. bad ***, but not a pain in the ***. Lots of power, you can use a stock clutch. But if you feel you need more, get one ported. Night and day. fulltiltrider has a 310 and hes a pretty big guy and he says he lovs it.

[Rich250RRacer]

Originally posted by DEERCHOOPER
lets just start with the bore for now. all those riding conditions require port and polish.

everyone said the same thing with my 450r build. you cant have a motor do it all, i got it. i know im working on a 2 stroke now and things are different, but ill try to find a happy meadin.


8 ball bearings, check.

Those bearings are pretty much standard on all CR250's too Terry, not just CR500. I use them on all my rebuilds. Part number 91008-KAE-731 if my memory serves me.

[DEERCHOOPER]

thanks rich.

so a 310 should do it?

[mxduner]

Originally posted by DEERCHOOPER
thanks rich.

so a 310 should do it? I went with a 310 non pv, it rips great but revs real fast for my taste. a properly tuned pv would be nice for xc.i hear the 330 and 350's rev a bit slower.next time i'm going 350pv.hope that helps

[zedicus00]

http://www.cpindinc.com/pub/part_list?manufacturer=2

if you are going all out, pick from that list. they are as far ahead of the pro-x as the pro-x is ahead of the stock.

also i would say go for good all around power, itl do great everywhere other then TT, and you can regear when headed to the TT track to get you into power.

[Honda 250r 001]

damn i didnt notice that they made a 310 puma kit! Hell i would love to have one of those. Whats the pricing on those puppies?

[zedicus00]

pricey, but i hear their 310 will EAT 350/370 pro-x set ups. theres a dealer links page on their home page. fire off and email and get a quote.

[DEERCHOOPER]

whats the limit before you have to bore the cases?