I just purchased a 250r and have been having a blast on it!!! I have a question on compression.
What is the lowest compression to run before I should rering the engine? This is my second two stroke to own and I am a little rusty on this subject and could use some info.[img]i/expressions/face-icon-small-confused.gif[/img]

 

Yo DaBeechman we need your help over here!!!........late,zubbeyboy

 

You should run it until you notice a significant decrease in power.

 

At 150 lbs it's time to open it up, normally they're around 170 depending on elevation and such.

 

If you do a compression check, use that as your base figure. Check it every once-in-a-while, use the same tester and use the same method so your numbers remain accurate. When you see a 10% drop, time to tear into the top-end.
And why just re-ring?
You reasonably ought to replace the piston every 30-40 also, and while at it, bore/hone the cylinder as needed.

 

liftkit
what year is your R and whats all been done to it and how much u pay just curious i found a R i might buy but i want to see what eveyone else is payin

 

If you get below 125 lbs. then it needs to be done. I think stock is around 140lbs. You won't have 170lbs unless someone has modified it. Remeber to hold the throttle open when you kick it over(checking comp.). I run 180lbs. of compression in mine. When it gets down to 160-165lbs, I open it up. Good luck.

 

I've got 2 stock motors and a new Snap-on comp gauge, the 85 ATC goes 190 and the 88TRX reads 170. If your gauge/hose adds volume to the cylinder it will read lower. The schrader valve that holds pressure in the gauge should be in the fitting that screws into the head so you get an accurate reading.

 

It is an 86 and the guy that owned it restored it from the ground up. He painted the frame dodge candy apple red, replaced all the brakes and bushings, installed graydon proline nerf bars, an ac bumper, ac garb bar, fmf header and silencer, rejeted card, uni air filter, carbon fiber hood with flames and a carbon fiber gas tank cover. The motor was bored and it had brand new holeshots and wheels with omf radiator shrouds. It had an fmf graffix kit with matching gripper seat but the stickers came off. I bought it off ebay in jacksonville florida for $2,900.00. We were going to a fun ride at mapplesville, AL that weekend, so I drove from there on to jacksonville to pick it up. It was 700 miles from were I live.[img]i/expressions/face-icon-small-happy.gif[/img]

 

I was told that any where between 140 and 110 was ok, but when it droped bellow 110 to tear her down. I dont think the motor has been ported, but it has been bored. I cant remember how much it was bored though.[img]i/expressions/face-icon-small-confused.gif[/img]