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Post by miker on Dec 14, 2007 7:49:01 GMT -5
I was looking at the Yamaha parts diagram before pulling my right cover for the first time... looks like there's only two things inside, the anti-wet-sump valve and an oil seal (item #7) that appears to be around the crankshaft end? What is this seal for? The crank doesn't penetrate the side cover, is there an oil galley ending there or something like that? Anything else I should know before pulling the cover, besides "don't disturb the kickstart spring"? About to do the big polish. About time!  miker |
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Post by bigshingle on Dec 14, 2007 10:34:33 GMT -5
The end of the crankshaft is hollow and fits into that seal.
On the other side of the seal (in the case) is a reservoir with an oil passage running directly from the filter chamber.
The seal lets pressure build up in the reservoir and forces oil into the crankshaft.
I've never pulled the crank, so I don't know where the oil goes from there.
Outlets in the crank for oiling bearings ? (similar to the way the rocker arms are lubricated.) Or is that oil cooling something? — dunno.
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Post by miker on Dec 14, 2007 11:36:26 GMT -5
Sounds important, I'll be nice to it. Thanks!
miker
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Post by caferacercarl on Jan 5, 2008 2:00:11 GMT -5
Thats the oil feed to the big end bearing, its critical and should have a circlip holding the seal in, flat side of seal facing towards engine, see if you can get hold of VMX magazine,copies 29,30 and 32 for the rebuild article, regards Carl
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Post by chew652 on Jan 5, 2008 9:52:54 GMT -5
The microfische For 1979 shows no circlip to hold the seal in but the 1981 fische shows a circlip.I wonder if the difference is because Yamaha modified the oilpump cover for more pressure after 1980. I looked at my '79 clutch cover and concluded if the seal was pushed in further it would cover the oilfeed from the pump. Do the later covers have a taller boss to accomodate the circlip? Do you have to buy a new clutch cover if you update your oilpump?Also both fisches show the open side of the seal towards the crank but the Clymer manual says the seal lip shoud be to the outside  . Lordy ,too many variables. Who knew opening up the engine was opening a can of worms? |
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Post by caferacercarl on Jan 7, 2008 1:08:18 GMT -5
The seal hole can be deepened, the circlip groove is already there but you are spot on, you need to dremel the oil feed hole to make sure it is not blocked when you insert the seal that couple of mill further in, Yamaha made a boo boo and issued a circular to all dealers at the time, I have a copy of it, definately flat side of seal facing you when you look inside the cover,that way the more pressure fed into the area,the more the seal actually seals if that makes sense? [too many seals? grab a club!?] Carl.
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tc
Full Member
Posts: 139
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Post by tc on Jan 7, 2008 5:57:28 GMT -5
Carl is it worth fitting a later oil pump to my 78 sr ?? TC
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Post by caferacercarl on Jan 17, 2008 1:37:25 GMT -5
Not critical, but pay attention to rotor condition and renew the little oil seals in the pump,the three bolt pump is fine,just carefully apply sealant around the outer edge of the outer pump cover."carefully" [not much], and its fine. regards Carl.
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. Lordy ,too many variables. Who knew opening up the engine was opening a can of worms?