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Can you replace piston rings on 4 stroke?

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I have an 06rmz 250 that I am about to adjust the valves on. Only one on the exhaust side is out of spec but I figured while I was there I could replace the rings. I noticed my bike does not have as much compression as my brothers bike (identical rmz 250) and thought that could help. I havent seen anyone, however, say whether or not that is ok to do on a 4 stroke. Bike probably has about 60-80 hours on it.

Any help would be greatly appriciated, Thanks!

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is this a joke?

Sorta.... But as far as I know people do replace their rings in the 4Ts.. oh i thought you replied to me.... stupid email updates...

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First, adjusting the valves is a totally different job than replacing rings. To replace rings, you will need to totally disassemble the top-end. Back in the old days of air-cooled low-performance 4strokes, putting rings in a 4 stroke made sense, as the pistons would last a long time. In today's modern 4 stroke, the pistons have a much shorter lifespan. If you are going to do all the work to disassemble the engine, you might as well replace the piston.

BTW, your lose of compression is probably due to the valves being out of spec. Hopefully you can shim them. Otherwise, things are going to get expensive.

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First, adjusting the valves is a totally different job than replacing rings. To replace rings, you will need to totally disassemble the top-end. Back in the old days of air-cooled low-performance 4strokes, putting rings in a 4 stroke made sense, as the pistons would last a long time. In today's modern 4 stroke, the pistons have a much shorter lifespan. If you are going to do all the work to disassemble the engine, you might as well replace the piston.

BTW, your lose of compression is probably due to the valves being out of spec. Hopefully you can shim them. Otherwise, things are going to get expensive.

Yeah i have heard that but only the left exhaust is out of spec so I didnt know if it could lose that much compression. I know they are two separate jobs but I don't plan on keeping this bike too much longer as I have a new one, so I would like to go as cheap as possible... Then again I should probably just not touch it!

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Yeah i have heard that but only the left exhaust is out of spec so I didnt know if it could lose that much compression. I know they are two separate jobs but I don't plan on keeping this bike too much longer as I have a new one, so I would like to go as cheap as possible... Then again I should probably just not touch it!

how did you determine it has lost compression?

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how did you determine it has lost compression?

My brother has the same bike that we bought both brand new. His seems to have more compression and I don't recall them being that much of a difference when we got them.

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My brother has the same bike that we bought both brand new. His seems to have more compression and I don't recall them being that much of a difference when we got them.

how are you determining the compression? just by kicking it over? Or are you doing a compression test? kicking it over will really tell you nothing. Just having your valves out of spec can decrease the compression at a certain point in the stroke. And you can also adjust the decomp. mechanism on some bikes. If that's out of spec your decompression mechanism can be opening too much or too little changing the feeling of the compression while kicking.

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how are you determining the compression? just by kicking it over? Or are you doing a compression test? kicking it over will really tell you nothing. Just having your valves out of spec can decrease the compression at a certain point in the stroke. And you can also adjust the decomp. mechanism on some bikes. If that's out of spec your decompression mechanism can be opening too much or too little changing the feeling of the compression while kicking.

he said it seems to have more compression. so obviously it's a seat of the pants assessment.

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haha yeah two different things don't worry about the rings just check the valves if ones off pull the rockers off and replace one of the shims

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