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52 R25/2 kick start noise/trans issue

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Posts: 8225
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

Re: 52 R25/2 kick start noise/trans issue

Post by schrader7032 »

I have the R25 - R25/2 workshop manual but it doesn't show any specs for the clutch disk thickness. I looked at my notes when I overhauled by R25/2. I measured about 7.1mm for the disk thickness. I haven't had any issues with using it so far.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

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Posts: 120
Joined: Fri Oct 27, 2006 3:00 am

Re: 52 R25/2 kick start noise/trans issue

Post by vechorik1373 »

The R24 through the R25/2 used a 7 mm thick clutch plate, part number 21 21 0 070 005
The R25/3 through the R27 used a 5 mm thick clutch plate.
The R25/2 uses 3 clutch coil springs, and the part number for them is 21 21 0 070 126.

Now, the number one reason you would have a slipping clutch, is a oil soaked clutch plate. The source of the oil, usually is the input shaft seal of the transmission. When that seal fails, the centrifugal force of the spinning shaft will throw the oil out onto the clutch plate. Once a clutch plate gets oil on it, it is done. You can never get the oil out of the fiber material, no matter how well you clean it. Heat will cause the oil to come to the surface again, and it will slip again. Throw it away and buy a NEW clutch plate. And thoroughly de-grease the spring plate and outer thrust plate. It wouldn't kill you to replace all 3 clutch springs also, while you have it apart.
But the most important thing, is to replace the oil seal on the input shaft of the gearbox, which is the source of the oil leak.
Technical Adviser, Former owner, Bench Mark Works
662 312 2838 cell 9 am to 4pm CST PLEASE!

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