Topic: The great oil mystery

[Red750K1]

Hey, I've been noticing that I'm using a bit of oil, about one pint between changes, on my 1971 Cb750. I re-ringed it and rebuilt the motor with new gaskets. The only seal I changed was the output shaft seal. I know my early bike has no exhaust seals so they will use a bit of oil.
My main concern is that I noticed when I remove the stator engine cover, there is oil in there. Not a bunch but a few shot glasses full or so. Is there a seal behind the rotor that I should change? I looked at my clymer's but it didn't look like there was a seal there.  Any ideas?  Thanks!!!

[Bob Wessner]

That small amount of oil you are finding behind the cover is normal. Unless there is a gasket leak for the cover, that's not your source of oil loss.

[Sporkfly]

From the reading I've done on the boards that's normal, but I could be wrong. What color is your exhaust? Any drops below the bike when parked?

[Red750K1]

All the gaskets are tight, bike has never (knock on wood) leaked a single drop. The bike burns a small bit of oil untill it warms up, very little smoke then its fine after a couple miles.  Why would there be oil in the stator cover?

[kghost]

All the gaskets are tight, bike has never (knock on wood) leaked a single drop. The bike burns a small bit of oil untill it warms up, very little smoke then its fine after a couple miles.  Why would there be oil in the stator cover?

Lubricates the starter gears and such.

[speedy gonzalais]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

[bwaller]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

There is no seal on the left end of the crank so a little oil in the stator cover is normal.

[KingCustomCycles.com]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

There is no seal on the left end of the crank so a little oil in the stator cover is normal.

If it can drain back to the case it is normal, if not, should be sealed, I just can't remember that level of detail without tearing one down to look.

[Sporkfly]

Smokes at start and after a few miles it goes away... Sounds like valve seals.

[eldar]

How much gets into the stator area? I understand a few drops but you said a few shotglasses worth and that is a lot.

[kghost]

Theres a fair amount of oil that gets in the Stator on the 750's.

The fact that there is oil there is no mystery theres supposed to be oil there.

More than a few drops.

Theres no seal on the left bearing between the crank and the stator.

Theres not supposed to be.

The starter gear and the sprag clutch for the starter need the oil lube.

The stator shouldn't be half full mind you....but theres always at least a shot glass full when I take them off.

[eldar]

See now that is odd to me as I never have more than a few drops.

[kghost]

See now that is odd to me as I never have more than a few drops.

Later engine perhaps? length of time between running and disassembled?

[WFO]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

I would agree also are you sure there are not leaks on the bottom that you might not have seen?

[kghost]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

I would agree also are you sure there are not leaks on the bottom that you might not have seen?

If you agree with that you don't know 750's.

I won't comment on the 650 as I don't have one....but theres sure the hell supposed to be oil there and no seal. Trust me I have 6 of them

Greased? Last engine with covers I saw that needed greased was a 1935 vintage Kinner 5 cylinder radial.

[WFO]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

I would agree also are you sure there are not leaks on the bottom that you might not have seen?

If you agree with that you don't know 750's.

I won't comment on the 650 as I don't have one....but theres sure the hell supposed to be oil there and no seal. Trust me I have 6 of them

Greased? Last engine with covers I saw that needed greased was a 1935 vintage Kinner 5 cylinder radial.

My point is any oil in there probably isn't good but if you think so what the heck do i know we are all here to learn including me............

[kghost]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

I would agree also are you sure there are not leaks on the bottom that you might not have seen?

If you agree with that you don't know 750's.

I won't comment on the 650 as I don't have one....but theres sure the hell supposed to be oil there and no seal. Trust me I have 6 of them

Greased? Last engine with covers I saw that needed greased was a 1935 vintage Kinner 5 cylinder radial.

My point is any oil in there probably isn't good but if you think so what the heck do i know we are all here to learn including me............

Kinda in a mood..so sorry didn't mean to get pissy.

But theres supposed to be oil there.

[WFO]

You Say a pint between changes how many miles? Also oil in stator cover any shafts coming out of the engine will have seals any oil coming through is not normal. anything that would need lubrication behind the covers should be greased.

I would agree also are you sure there are not leaks on the bottom that you might not have seen?

If you agree with that you don't know 750's.

I won't comment on the 650 as I don't have one....but theres sure the hell supposed to be oil there and no seal. Trust me I have 6 of them

Greased? Last engine with covers I saw that needed greased was a 1935 vintage Kinner 5 cylinder radial.

My point is any oil in there probably isn't good but if you think so what the heck do i know we are all here to learn including me............

Kinda in a mood..so sorry didn't mean to get pissy.

But theres supposed to be oil there.

why? and yes iam curious.

[kghost]

Ok heres the oil flow.

[kghost]

Heres the Exploded view of the other side.

See number 12? Thats the Stator. See the gear behind it? Thats the gear that has the sprag clutch on it for the starter.

It has a bronze bearing and sits there when the engine is turning.

Starter turns the gear...gear contains the sprag clutch...sprag clutch spins the engine when the starter is engaged.

Because the gear only spins when the starter is engaged its oil lubed.

[Sporkfly]

There have been a few posts about this in the time I've been here and I'm still agreeing with kg, it's normal.

Now I just have to get myself a 750 so I can put some of the knowledge I've gathered here to use...

[kghost]

If this question of oil behind the stator continues....I'm gonna go pull mine off after running it and video tape it. 

If you click on the pictures in my post they get bigger.

[fuzzybutt]

the k-6 motor in my 74 740k has ALWAYS had an ounce or 2 of oil behind the stator, thats likely the reasoning for the seal thats part of the wiring harness.

[speedy gonzalais]

Ok thats shocking, How does it work? I thought tht the only thing that would need oil in a altenator would be the bearings, The rest should be dry too much oil in there and the altenator wont work propperly.

[eldar]

Maybe they changed the bearing or something in there to prevent so much oil from getting in on the later engines.  Maybe that accounts for the difference. I think in the whole time I have had the bike, I have pulled the cover off twice and only had a little trickle of oil. I will be pulling things apart this winter if I have time, I hope I have time. I will see what I see I suppose. Maybe I will post the pics on dis-assembly online for all to see.