what is sleeving and replating?

[tman12345]

what is sleeving and replating?

[drew416ex]

Resleeving is taking out your old sleeve and installing a new one. Replating is when they coat the sleeve with a hard material to resist wear. The material is called nickasil and it comes on the 450s and many 2-strokes.

[tman12345]

whats a sleeve?

[drew416ex]

The sleeve is the guide that the piston is inside of.

[GPracer2500]

Here's a picture of a 400EX cylinder sleeve. It's the far left.

http://www.lukesracing.com/XR440.jpg

A stock sleeve will allow a certain number of over sized bores. After that if you want to go back to the original bore size or go larger than the original sleeve will allow, you would have a machine shop install a new sleeve (i.e. re-sleeve the cylinder).

Sleeves are generally made out of iron. Sleeves are pressed into the cylinder or "jug". Since the cylinder itself is made out of aluminum, a sleeve is needed that is made of a more durable material. Pistons are aluminum but the piston rings are made of a type of steel. The rings would quickly destroy an aluminum bore, so iron sleeves are used for the piston to move up and down in. Unless....

....the bore is "coated" or "plated" with a special, super-hard surface treatment. These coatings can be applied directly to the walls of an aluminum cylinder. There's no need for a sleeve of any kind when a bore is plated. Now, if a cylinder originally came with an iron sleeve and you wanted to convert it to a coated bore, then you'd either plate the existing iron sleeve or you'd remove the iron sleeve and install an aluminum sleeve and plate that. But most plated bores don't have any sleeve at all.

[tman12345]

oooo, alrights thanksfor the help.

[drew416ex]

Actually like I said before, the 450s that are plated like the honda, are sleeved and plated.

[GPracer2500]

Originally posted by drew416ex
Actually like I said before, the 450s that are plated like the honda, are sleeved and plated.
Sure?? :confused:

This pic shows one from the top. No sleeve there that I see.
http://i15.ebayimg.com/08/i/000/bc/71/2450_1.JPG

Here is a damaged cylinder. Again, I see one continuous piece of aluminum. Notice the crack on the left--it runs through the protruding skirt of the cylinder and all the way up the side of the cylinder's exterior.
http://i187.photobucket.com/albums/x42/Knowpig/DSC01225.jpg

If you're going to design a cylinder to have a coated bore, there's no reason to use a sleeve. If makes more sense to make the whole cylinder one continuous piece of cast aluminum. You can sleeve one--there are aftermarket sleeves available--but a sleeve doesn't make sense with a coated bore unless you're modifying it.

[drew416ex]

Ok well the one I saw must have had an aftermarket sleeve in it.