First, we would like to thank Eric Lester from Elite Performance for allowing us into his shop to get the skinny on how one goes about replacing a piston and ring set on one of the newer 4 stroke engines.
Eric gave us a heads up that he had a Kawasaki 450R in the shop due to a damaged piston and cylinder and we would be free to come hang out and try to capture all the steps in this process.
Erics customer was riding when his engine started loosing power. Immediatley the rider knew there was a major issue with his engine and shut it down as soon as possible. Knowing the damage was internal, his KFX was taken to Elite Performance for a diagnosis and subsequent repair.
The engine did not need to be removed for this procedure, however Eric wanted us to have full access to all angles if needed to do our thing!
The first and foremost thing everyone should have for their ATV is a good shop manual. It will walk you step by step through almost everything and can save you the cost of it the very first time you repair your machine yourself versus letting the dealer have a crack at it
A few others things will make any job go a little bit faster and should help prevent some issues....
1) Get the correct manual for your machine
2) Get the tools you need BEFORE you start
3) Make sure you have all the parts you need BEFORE you start if possible. With a piston needing replaced, until you open the engine up you wont really know what will need to be replaced, however have as many of tehe parts you need on hand for most jobs.
4) A clean work area and hopefully a clean engine/part to work on.
There are a few tools for this job that you may not have and should either buy or rent and have a working knowledge of what they do and why they are used.
Beyond the typical sockets and wrenches, you will need:
With this engine being on the bench, a spare set of hands will be needed at a few points to help steady the engine. A helper always comes in handy even on an "In" frame install.
The first step in the actual work will be to remove the slotted inspection covers. This will allow you to bring the engine to TDC (Top Dead Center)
The cam Caps are next on the list and they should be loosened in a pattern so that they come loose evenly as to not put uneven pressure on the caps. The manual will show you the small details, just take your time.
Using a pick or very thin flatblade, the cam caps can be removed, but they need to be loosened first and again, they should be taken up evenly as to not cause damage to them.