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First time rebuild

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I have a 2002 CR125R that when I bought looked like it was never used. I tore it down some, inspected and put back together and been riding it. I just passed 21.5 hours (on the hour meter I mounted) and I'm looking at replacing piston/ring/pin/clips/upper con-rod bearing. The manual also mentions replacing the reed valve's (valve only) and I'm looking for some input on this. I'll pull it apart this week and take a look, but if they're not chipped/damaged should I still replace them?

Edited by MSFIT

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I have a 2002 CR125R that when I bought looked like it was never used. I tore it down some, inspected and put back together and been riding it. I just passed 21.5 hours (on the hour meter I mounted) and I'm looking at replacing piston/ring/pin/clips/upper con-rod bearing. The manual also mentions replacing the reed valve's (valve only) and I'm looking for some input on this. I'll pull it apart this week and take a look, but if they're not chipped/damaged should I still replace them?

reeds are cheap and easy to replace. If its been awhile since they was replaced then it would be a good idea. Even when they look decent they can be weak and cause issues.

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run a compression test on the top end, also remove the exhaust to visually inspect them, if you are trail riding its possible everything is still fine.

 

and as for the reeds, you can usually tell when they need to be changed, once they get to a certain age they become weaker and will start to gap.

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195 is a good reading, likely all is still fine, swapping the top end is not needed with that compression unless you really want to.

 

what type of riding do you do?

 

Of these 21 hours the majority was trail, one day of moto (2 hours), and one hare scramble (1.5 hours).

 

The bike still runs great, I was just going off hours and the book :)

Edited by MSFIT

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the book quotes are for what these bikes were made for, MX racing.

 

have a look at the piston and cylinder and you will know for sure, if it looks good i would run it and do comp checks every 5 hours to monitor wear.

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