Author Topic: 76 RM125 piston in 79 RM125 cylinder  (Read 1031 times)

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Offline Tomas

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76 RM125 piston in 79 RM125 cylinder
« on: July 22, 2013, 04:07:53 PM »
Just would like to know forum's opinion on using piston from 76 RM 125 in 79 RM 125 cylinder. I have 79 RM125 cylinder on last over size(56) and would like to know if 76 RM 125 piston would fit. It would allow another overbore or two and would take bore to let say 57. Cylinder liner is about 3mm thick with 56 mm piston in it so there may be enough for another overbore or two. I know that piston pin in 76 is the same diameter as 79 but thats all. Dont have 76 piston to compare with 79. Any ideas? Anybody ever attempted this?
Thank you for your help
Tomas

TM BILL

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Re: 76 RM125 piston in 79 RM125 cylinder
« Reply #1 on: July 22, 2013, 05:04:23 PM »
76 RM 125 takes a bigger gudgeon pin 16mm 79 14mm  ;)

Offline Tomas

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Re: 76 RM125 piston in 79 RM125 cylinder
« Reply #2 on: July 22, 2013, 05:52:46 PM »
Thank you TM bill.  According to Partzilla.com 76 125B? and 79 125 uses the same small end bearing. But it can be wrong   >:( 

Offline Dono113

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Re: 76 RM125 piston in 79 RM125 cylinder
« Reply #3 on: July 23, 2013, 10:15:07 AM »
Bill is on the money, I have a RM125A, just did a bottom end rebuild, larger gudgeon pin. I tracked down a whole bottom end off "D" as well as another crank from a mate in SA
1983 CR125R
2003 CRF450R
CB750K1
2005 YZ85
1969 TS 250