cylinder wear

[Coop]

It hasn't been mentioned, but make sure your air filter is cleaned, oiled, and you used grease between the filter and air box. If it is in fact dirt (not saying it is without seeing it) poor filter maintenance is your main cause of it getting in there.

[RedFoxCR]

Thanks man! The filter is as moisturized as my girlfriend's p****, so is its inner side also:)))))) ,  and screwed properly. But - correct me if i'm a fool - the sand particles should scratch marks ALONG the cylinder - not AROUND? And they ain't no along, but around the inner side of the cylinder.

The compression is slightly under stock, cause of a small pisston. It's only 66,32! While my bore is 66.4 and the bike is old.

[Chokey]

The marks you're seeing are called chatter marks. They are caused by too much clearance allowing the piston to rock in the bore. If you're running a cast piston you're lucky it hasn't shed a skirt.

[RedFoxCR]

Wow, that must be correct! I've been used a very small Vertex, so small, that it would swing back and forth when pressed on the skirt by finger! After it finally felt apart i installed a kit of Namura. It doesn't swing, and the clearance seems tiny, but....... It's written 66.32 on the top of it, while my bore is 66.4!!!!! And the cylinder is rather old!!! (The previous owner seems had been using Wiseco, replacement diameter C)
A fella suggested just to ride harder, so the pisston gets hotter and the huge clearance disappears. Says, it's a preferrence;small pistons get skirt falling apart, while big ones make overheat or that kind of thing. What do you think?

How big is the proper clearance???

[Chokey]

The specs on a Wiseco Pro-Lite are .015" if I'm not mistaken. Your OEM specs for a cast piston were probably .002-.003" or somewhere in that range.

Your cylinder is worn out. Buy a new piston and send the piston and cylinder to a re-plater like Milllenium Technologies or Powerseal USA and have it re-plated. It will be better than new.

[ford832]

The marks you're seeing are called chatter marks. They are caused by too much clearance allowing the piston to rock in the bore. If you're running a cast piston you're lucky it hasn't shed a skirt.

What he said.I think your engine's a ticking time bomb Red.

[RedFoxCR]

Holy shit!!! Is there any way without a new cylinder?

[Chokey]

Holy shit!!! Is there any way without a new cylinder?

Why would you need a new cylinder? Just send your cylinder out to be re-plated. $200 and it's better than new. Millenium Technologies and Powerseal USA both use plating compositions and techniques that are superior to OEM.

[RedFoxCR]

You mean, plating some Nikasil onto the cylinder?? But in our country no one does re-plating! The nearest country in Europe doing that is Poland.
Nikasil seems fine. It should be a bit blue inside, shouldn't it?
wHAt about buying a sleeve?

[Chokey]

You mean, plating some Nikasil onto the cylinder?? But in our country no one does re-plating! The nearest country in Europe doing that is Poland.
Nikasil seems fine. It should be a bit blue inside, shouldn't it?
wHAt about buying a sleeve?

Oh I'm sorry, I didn't realize you lived in Europe.

I guess in that case the decision would be based on cost. How much difference in price would there be bewteen installing a sleeve and buying a new cylinder?

While I never recomend a sleeve over a re-plate, if re-plating is not an option and money is an issue then a sleeve is the next best alternative, as long as you can find a GOOD machine shop that can bore it true and match the ports properly. If not, you're better off buying a new cylinder.

[ford832]

I'd try giving it a light hone(yeah,even though it's plated)see how the marks look and measure it with a bore gauge.If the bores not too bad and not tapered too badly it may survive.Honda typically used A and B cylinders(it's stamped on it)and corresponding A and B pistons.I think the A piston/cyl are smaller so if you have a slightly worn A cyl you can usually fit a B piston-or vice versa.Maybe some Honda types could chime in here......

[RedFoxCR]

Sorry, i can't do re-plating. I live in RUSSIA. No one does re-plating in our country. A man that taught me to ride, uses old cylinders as pen stands or keeps small parts in them (