RM 125 Cylinder

[rudyrood]

I recently had the cylinder micd and here are the numbers.54.02,54.03,53.997.It looks like the specs are 54mm x 54.1mm bore and stroke.Is this cylinder in tolerance?

[MXtras]

Well - it's only out by .001" (.03MM = .001"). It's worn, but considering the plating is usually thicker than .003"-.005" (IIRC), I think you are OK for now.

I assume the lowest number was at the bottom (original size), the next number is mid and the largest number is the top - below the wear ridge. With this wear, your ring groove will wear a tad faster than a new bore, so keep an eye on the ring groove when re-ringing.


Scott

[rudyrood]

Thanks for the response Scott.
Do you have any suggestions before I install the new piston and ring?

[MXtras]

Is there any hatch left in the worn area? I doubt it. A new ring in a non-hatched cylinder will not seat properly. You might want to investigate honing the cylinder.

Keep in mind - if you race or ride hard and there's no hatch left it's replacement or re-sleeve time. For recreational use you will be likely be fine.

Scott