BannedCR500Riders.com

Tharrell wrote:Pull the topend.
Check your ring end gap.
It may be that simple.
They're supposed to wear.

Are you saying re-ring it if they are out of spec?

For sure!
But, if the rings are out of spec, the bore MAY be also.
One other thing.
Usually I put a new topend on a bike that needs rings.
Back in the day when I raced a lot I would just put rings in on a regular basis.
Usually 3-4 races on a 250-500 more often on the 125's waaaaayyy back in the day.
The intake skirt will probably be weak and you don't want to grenade the bottom along with the cylinder.

Mic the piston, bore, and check the end gap.
While you have it tore down, check any play in the crank.
I don't have the specs in front of me but someone here will post them I'm sure.

My usual scenario when rebuilding the top includes crank seals too but, that's just me.
The only thing I don't reseal are the cases on a topend rebuild.
I do a leakdown test after a rebuild also. I hate surprises.
Do it right and maintain it and you're good for a long while on a 500.

the only way to know if anything is wore out is to take it apart and measure. doesnt sound like you have a bore gauge or micrometer though. machine shop will probly measure it for a 6pak of beer then youll know what you have. pressure gauge doesnt tell you diddly sqaut unless you knew 6 months ago it had 180psi then it may be a indication something is worn. you might see low psi with a scalloped jug, thats why their there....... to bleed off pressure. doesnt necesarily meen anything is worn. hone will only make the hole bigger, thats not what you want. run it as is or bore to the next .010". any of this make sense ?

they should measure it for 0$

No gauges, I was trying to do it commando... Have issues with locals shops and honestly wanted to get it done in a few days and not miss riding. If I have to send it off Ill send it to Adam.

Being that I dont know the history on the motor, Im worried that it will tweak out on me and I'll be out more than a topend. Guess I'll quit being a pussy and run 10-20 tanks through it and check the compression again.

Pull off the jug and post some CLEAR photos of the piston and bore.

You can prolly' just ring what you got and run it for a long time.... no worries.


This is a 4 year old Vertex. Bel Ray sticky blue oil + 927' made it last a long time, with more life in it.

I sprayed it with fogging oil, and bagged it up. Its 100% usable.

AlisoBob wrote:Pull off the jug and post some CLEAR photos of the piston and bore.

You can prolly' just ring what you got and run it for a long time.... no worries.



This is a 4 year old Vertex. Bel Ray sticky blue oil + 927' made it last a long time, with more life in it.

I sprayed it with fogging oil, and bagged it up. Its 100% usable.

really, no hone just ring and go? Need to get a gasket set in here then...