Sleeves

If you are doing a SeaDoo top end, Yamaha complete rebuild, or just fixing that one Kawasaki cylinder, our jet ski sleeves will help you get the job done quickly and efficiently. These cylinder sleeves are designed to repair broken or worn out sleeves and get your PWC engine back to factory specifications.

As a side note, and some interesting reading, the oldest and most common method of cylinder design is a cast iron block that is machined with a cylindrical bore directly from a solid casting. There is also a cast iron block design that incorporates a sleeve that is pressed into the iron block. Generally iron block motors weren't very successful in small engines (ie jet skis or PWC). Most small engines used in vehicles and equipment need to be light and mobile. This makes cast iron blocks undesirable. A lot of single cylinder motors used in lawn mowers, construction equipment, scooters, small tractors and small motorcycles used cast iron block motors in the early years. These began to disappear in the 60's and they were replaced by aluminum block motors with cast-in iron liners.

This opened the door for new lightweight motors that could be used in many more applications and in bigger displacements than ever before. This was accomplished by placing a cast iron sleeve into the mold before the molten aluminum was poured into the mold. This made the sleeve an integral part of the cylinder block. The sleeve usually had locking rings or flanges around the outside to prevent it from slipping in the casting as the engine expanded from the heat generated by the combustion process. A major problem occurred often when air pockets would develop during the casting operation around the sleeve. This caused hot spots and often caused premature engine cylinder failure.

Next came the aluminum block with a cast iron sleeve that wasn't cast-in, but installed in the block after casting. The cylinder bore of the aluminum block was machined to 3-5 thousands of an inch less than the sleeve diameter, then heated to around 600° Fahrenheit. The sleeve is dropped in. When the block cools the sleeve is held in place by the interference fit and the flange at the top or bottom of the cylinder. This cylinder can be rebuilt by simply re-heating the block to 600° and removing the old sleeve and replacing it with a new sleeve. Of course the finish bore will have to be machined to size and honed.