Cylinder question 98' RM125

[Reid55]

     

What is the cylinder on my 98' RM125 plated with if plated at all? I haven't deglazed it yet and everything is "very" smooth with no signs of crosshatch. Just want to know if I should be looking for the crosshatch when I start to use the #2 scotchbrite. The piston was pretty far gone with blow-by almost all the way around. This is my first topend rebuild and I want to make sure I don't reuse a cylinder that I shouldn't.

[ossagp1]

Judging from the year (98) I am guessing you aren't competing regularly with this rig. If you can't find any place that the plating is worn off (factory they came with a plated aluminum cylinder. every company has their own unique name), then I would say to reuse it. I use an aluminum oxide hone,,,anything from about 320 to 360 grit (seems to just depend on the brand) makes me happy. Lots of them get reused when there is just a little plating missing around the exhaust valve etc.

[RMer98]

hi as far as i new they were nikel plated but as far as i know well hey from rich to poor i am a novice
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[Reid55]

Thanks......I did notice some missing just above the exhaust valve. So what about the crosshatch. Will it be there underneath the smooth surface that I have now? I'm gonna be using the scotchbrite for the honing.........any tips or techniques I should know. Like I said, I'm ******* ** ****** on this one.

[ossagp1]

I dont often use scotchbrite, so I can't give you a good guess as to what you will find. Assemble the cylinder dry or nearly dry and the ring will seat pretty fast. It's an old trick. Just lube the bearings well, and don't go testing the extreme top end jetting as soon as you start it.

[Reid55]

I did happen to pick up a hone yesterday. Do you think I should use it or just run what I got. The piston gets here today, but I haven't done anything to the cylinder yet. In my Clymler manual under the inspection section for the cylinder it says this " Inspect the bore for obvious scoring or gouges. If damage is eveident, replace or resleeve the cylinder. The chromed bore cannot be bored or honed". That along with what was just said make me think I should just run it. Like I said before though, the piston was blackened almost all the way around below the rings. I looked for a micrometer yesterday to check the specs, but couldn't find one that would do the job. Should I really be so concerned?

[triplendo]

Run it!!

[ossagp1]

I would do like Trip says, the honing is up to you. Do it dry and it wont really matter if it is honed, they seat reasonably well.

[Reid55]

Done, seems good so far, still breaking it in. Thanks guys

[ossagp1]

Makes you all warm inside when you get one back together and it is running. Of course in Florida you should be warm all over.