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Discussion Starter #1
I'm rebuilding a 1972 TR6R and the 4 Aces rebuild DVD makes mention of a drive-side crank seal, but there wasn't one there when I tore it apart - which doesn't mean much, because somebody along the way put a jap main bearing in the case that started to wear out.

Now that it's going back together with new English bearings, I can't find any mention of a drive-side crank seal in the 1972 Parts Catalogue or in the Workshop Manual.

Am I missing something?

Thanks!
 

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I guess there's no need for crankshaft seals as the engine breathes through the primary drive case. The same would be true on the timing side as everything runs in oil there as well.

Just the observings of the "village idiot": Jim
 

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Hi again,

Just wondering....are you related to Gregory "Pappy" Boyington, by any chance??

Sorry, but I just had to ask: Jim
 

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The oil seal was installed in all bikes up to and including 1969. From 1970 onwards they omitted the oil seal and vented through a pipe from the chaincase. There are also I think 3 small holes to regulate the oil level of the chaincase. Prior to 1970, 20 grade oil was used, afterwards the same oil as the engine ( usually 20/50). There is some movement of oil between the crankcase and chaincase but not a lot. Generally some small amounts of oil mist get into the chaincase and condense in there to weep gradually back into the crankcase, the fumes escaping through the vent pipe which is usually routed out the back of teh bike.
 

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Discussion Starter #5
Thangew all. Jim - I'm not related to Pappy at all, on another forum, another former USMC enlisted guy had Chesty Puller for his avatar... so I had to get a good USMC avatar also.

Thanks for the replies... I read on a couple of other threads about the crankcase breathing through the drive-side case like that - I found the three little holes the oil is supposed to migrate through and made sure they're all cleaned out. The drive end of the crankshaft looks like there's supposed to be something covering it - like a seal.

But I guess not!

Thanks again!
 
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