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1980 CB 750k, rotor side oil seal

leo750k

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Is the oil seal behind the rotor coil serviceable without removing the motor and splitting the case? And is a minor oil leak/drip in this area detrimental to the coil, stater, or brushes?
Any info or advice is appreciated. I just finishing up installing a new rotor, and stater coil, don't want to chance ruining them. If I have to split the case to replace the seal, then I might put it off for a while. If all i have to do is to pull the rotor, then I will do it now.
Thanks for the help,
Leonard:cool:
 
No, cases must split to get it out.

http://www.cb750.com/threads/6454-79-CB750k-no-6th-gear

Go down to post #8 and download the imgur pic there and blow it up, or save it to your drive and blow it up even bigger. On the left end of crank it clearly shows the seal has a rib at the back of it that locks it in place and the cases have a groove cut to hold that rib in place. It stops you from simply pulling the old seal and knocking another back in the old school way, intended to have to split the cases to get it in. If you try to force the old seal out the cut groove creates a weak spot that may crack loose to have the entire seal support area break off scrapping the cases, you don't wanna go there.

Alts have run in oil before, it does not really affect the charging, but that type won't as the brushes themselves are the problem, they will burn oil at the sparking brushes to then burn the rotor tracks and then they will quickly drop way off in electricity carrying to not charge. The 750 and 550 SOHC can charge in oil because they don't have brushes running in oil. The coils of stator and rotor do not care.
 
Ya I see what you mean, it looks like it will also be necessary to un-cap the crank bearings too, so it can be lifted up just enough for the seal to clear that groove. I did also see some black streaks on the slip rings (looked like carbon) and I have been having a charging problem, even though the stater coil tested good, and the rotor, and volt. reg. are brand new. I think the oil (even though its not much) is giving me problems already.
Well thanks for the insight, do you think it would be foolish pull the motor, and split the case to ONLY replace the crank seals?
 
Your call there. The rotor tracks will carbon up even if the compartment is oil tight. Look at practically any alternator on earth. The brushes themselves are made of carbon.
 
No, cases must split to get it out.

http://www.cb750.com/threads/6454-79-CB750k-no-6th-gear

Go down to post #8 and download the imgur pic there and blow it up, or save it to your drive and blow it up even bigger. On the left end of crank it clearly shows the seal has a rib at the back of it that locks it in place and the cases have a groove cut to hold that rib in place. It stops you from simply pulling the old seal and knocking another back in the old school way, intended to have to split the cases to get it in. If you try to force the old seal out the cut groove creates a weak spot that may crack loose to have the entire seal support area break off scrapping the cases, you don't wanna go there.

Alts have run in oil before, it does not really affect the charging, but that type won't as the brushes themselves are the problem, they will burn oil at the sparking brushes to then burn the rotor tracks and then they will quickly drop way off in electricity carrying to not charge. The 750 and 550 SOHC can charge in oil because they don't have brushes running in oil. The coils of stator and rotor do not care.
Is it the same on earlier cb750's? 1975
 
im not that kind of mechanic. safe to say at the price, when i find oil on the bolts when removing the stator cover, shes toasted. good to know i got taken again. great community this one.
 
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