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piston question
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Posted by: theTman

how much over is a 310R...im not to moter educated

Posted by: punker69q

A 310 piston is not usually "rated" as an over size piston, like + 1.5mm over stock, but by it's real diameter. A 310 is usually a 295cc motor, so the base bore is 72mm, vs a stock bore of 66mm. For a 310cc pro-x cylinder, oversized pistons are avalaible up to 74mm for it's last bore, which is a 310cc motor, with the stock stroke.

Posted by: theTman

thanks, but i was just looking for how much over stock it is

ex. .10 .20 .30 etc

Posted by: 2004exrider

Since he's saying 1.5mm, . 040 is equal to a millimeter so it should be .060.

Jimmy

Posted by: punker69q

6mm over stock for the first bore, so this is 0.236'' over, yours may be bored over that.

Posted by: theTman

im so lost haha....i just need to know if its

STD
.10
.20
.30
.40

so i can order a new piston

Posted by: Jester

call esr or someone that sells prox pistons and ask them..

sounds like your confusing stock bore numbers with the 310 numbers.

Posted by: theTman

quote:
Originally posted by Jester
call esr or someone that sells prox pistons and ask them..

sounds like your confusing stock bore numbers with the 310 numbers.

i know it is a 310...just confused it all lol

sorry for the confusion

Posted by: Jester

when you see bores for std, .010, and so on, thats usually from stock bore, for oversizes you need to call to make sure you get the right thing.

Posted by: punker69q

quote:
Originally posted by theTman
im so lost haha....i just need to know if its

STD
.10
.20
.30
.40

so i can order a new piston

not any of those!!

open her up, get a decent caliper and measure the bore! Or since you don't know anything about motors, have someone who know what he is doing measure it and check if you need to get your cylinder bored!

Those pistons won't be stock honda replacement, but pro-x pistons made for their cylinders. I don't remember if wiseco or any others are making pistons for those big bores cylinders.

Posted by: punker69q

I also saw in the "show your 250r" thread that your bike is not running right now, so you can't just slap a piston in that motor without having the bore accurately measured and ajusted (bored + honed) to the piston size you will order for proper clearance. This is critical with those 2 stroke motors if you want it to be reliable.

Posted by: hondardr4life

Well ya see, .040 over is only like 258cc's. And .080 over is only a 265cc. You need to call someone like ESR, and tell them you need a 310 piston. Actually, you would be best off just sending your cylinder to any good name racing shop near you, and letting them do everything. That way you know it is done right, since you say you don't know much about motors.

Posted by: matt250r21

.08 over is a 262

Posted by: theTman

it already has a bored 310 CT racing head...i know more than what im making it look like i know, i know you cant run a stock head and a 310 piston and etc....just tryin to find out where i can get a piston is all

Posted by: Hoppedrap

http://www.ctracing.com/pistons.htm

Posted by: theTman

quote:
Originally posted by Hoppedrap
http://www.ctracing.com/pistons.htm

thanks!!