Cylinder life

[JimmyHoffa]

This is just a quickie question from a Nikasil noob...

Honda suggests piston replacement every 20 hours. How-a-bout those cylinder walls? The automotive engine builder in me says I need to at least hone every time the piston is so much as twisted in the bore, and removal of even the freshest of pistons DEMANDS rings and a hone. How long does Nikasil last compared to steel?

Essentially, how many pistons can I get to a cylinder?

Thanks,
-Jim

[GPracer2500]

Nikasil is extremely tough. Way, way tougher than a steel liner. I imagine you should be able to get many hundreds of hours of life from an OEM Nikasil bore. I've got a 95' CR250R that I bought used. It's had who knows how many pistons through it's OEM bore. The Nikasil is still in reasonable shape. I'd guess there is more chance of having a piston, crank, valve, etc. fail and take the cylinder/bore out before it just wears out from normal use.


And BTW, when you "hone" a Nikasil bore what you're actually doing is deglazing it, unless you're using diamond impregnated honing tools (which many or most machine shops don't even have). All a normal hone will do is clean debris from the existing crosshatch--restoring it, so to speak. Nikasil is too hard to actually install new crosshatch or dimensionally change the bore with anything but diamond hones.

[JimmyHoffa]

Sweet! You're that one guy who knows everything. You helped me with 400ex engine stuff before. I appreciate it.

Sorry about the hone slip up. I actually have a three-stone deglazing tool, so I'm set. Just switched words. All that jackhammering today... I think something bad may have happened to my BrAiN...

This Nikasil stuff... I know it's some type of ceramic, so it would follow logically that a porous stone hone couldn't take too much material off. That makes sense. I was just terribly confused by the bore in my friend's RM-Z 250, where the bike looked relatively young, but the ring had worn through the Nikasil to the aluminum, and lots of icky things happened. That's really all that threw me off. I'll just chalk it up to Honda being grossly superior to Suzuki, and a fairly lax maintenance routine on the part of the previous owner of my buddy's bike...