Boring and Honing Nikasil cylinder?

[hsr]

I am going to be tearing the top end apart on my 04 Honda 450r. I have been racing it for 2 years on the stock piston and rings. Although it has not shown any signs of power loss, compression, loss or smoking, I am going to freshen up the top end with a new piston and rings for preventative maintenance. I am hoping that I do not have to bore the cyliner, although my question is...if I indeed do need to bore the cylinder I am going to have to get it re-nikasiled correct? And lets say that it doesn't need bored out, would a simple hone job be alright??? Any help would be appreciated!

[GPracer2500]

If your old bore is not servicable then I think it might be cheaper to purchase a new OEM cylinder than to re-Nikasil the one you have. Honda 450 cylinders aren't that much. Check ServiceHonda for OEM and US Chrome and Millennium Technologies for plating.

But your current bore might be fine. Nikasil is some seriously tough stuff. I've got a 95' CR250 that's had who knows how many pistons on it's OEM bore. Unless your bore recieved some kind of damage (nicks, gouges, etc) it's probably dimentionally ok. Have a machine shop measure it if you want to be sure of it's condition.

With plated cylinders you're really deglazing them between pistons, not honeing them. Nikasil is too hard to hone with traditional honing tools. My guess is that most of the marks you'll find on your bore is material from the piston/rings/etc transfered on to it. You can usually get that off yourself or you could take it to a machine shop for deglazing.

If I had ball hone in 240 or maybe 280 grit then I'd use than do degaze. I don't though, so I scrub the bore with a scotch brite pad in soapy water. For tougher spots I'll wet sand. A ball hone is probably ideal for deglazing a Nikasil'd four stroke cylinder. But you can do an adaquate job deglazing with stuff you've probably already got.

[hsr]

Thanks for the info man. Chances are my cylinder is in good shape. I am just exploring all possible outcomes here. So a scotchbrite and soapy water will work for deglazing then? And say i measure my cylinder with snap gauges and then mic. my pison. What type of clearances should I be looking for???

[Johnny B]

hey hsr, where in pa are you located

[ricks450]

Originally posted by hsr
Thanks for the info man. Chances are my cylinder is in good shape. I am just exploring all possible outcomes here. So a scotchbrite and soapy water will work for deglazing then? And say i measure my cylinder with snap gauges and then mic. my pison. What type of clearances should I be looking for??? filler gauge will work. .004 clearance is your standard what new piston should be, and .007 is your service limit. .007 and beyond, and you need to replace your piston. this is the clearances between cylinder wall and piston. bore size should 94mm. hope this helps! like GPacer2500 said your cylinder is vary hard and unless its scarrd. more than likely fine. :)