CR250 Cylinder Help

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5/20/2018 11:28 AM

Hey guys, I picked up a recent project bike, 02 CR250. Long story short pulled the cylinder off and theres a crack in it with a lot of major scoring on the inside of the sleeve. I’m looking around to see if any other cylinders (later years) work with the 02 motor. Does anybody know if the later 04 year cylinders work or if you can get them to work with some modifications? I’ve seen in other forums theirs a list of all the changes they made from 98-07. I wasn’t sure if anybody has come across a similar issue and how did you guys fix it? Any help is much appreciated thanks.


5/20/2018 12:46 PM

As I understand it, 02-04 are the same other than porting changes and a slightly different power valve in the 04, along with a D-shaped exhaust port. Pipes will interchange between them.

05-07 are a flat-top piston along with the cylinder switching to a female outlet (the pipe fits in the cylinder as opposed to 02-04 with an exhaust flange that the pipe goes on). They also have different power valve access.

I believe you could use an 05-07 cylinder, but you’d have to use a matching pipe, piston, and possibly head.

If the crack is in the exhaust bridge, millennium can possibly fix it.

While you’re in there, I’d consider putting in an 05-07 OE crank-it gets rid of the shells on the 02-04 that can crack and ruin your day.


5/20/2018 2:22 PM

02-04 cyl's will interchange. Just need the corresponding yr. PV's as Honda reconfigured the exhaust port each yr..

05-07 cyl's can be used, but you'll need a domed piston, head, male expansion chamber & CDI..

The 02-04 models use a flat top piston.


Speak softly and carry a big stick.

5/20/2018 3:32 PM

I would shy away from repairing your existing cylinder and find a new/good used one. Maybe Millenium will take yours as a core and you can buy one from them.


If you're not mixing gas, you're not haulin ass.

5/20/2018 3:36 PM

Awesome thanks for the heads up guys. I talked to milinium twice and they said if it cracked between the power valve it would be better to buy a new cylinder because they’re unpredictable when trying to fix the crackin that area. I know a someone I may be able to get an 04 cylinder from so I’ll try that. Any thing else I should know trying to get this bike together?