an oil leak!!

[MotoMike]

Well the 450 has about 250 miles on it since it's recent ressurection. This morning I noticed a dime sized drop of oil under the engine. appears to be coming from the drive sprocket area under the right side cover. A quick look at the books don'tt really show what would be properly be described as an oil seal on any of the shafts that exit the case under that cover. It doesn't really look like the oil level would be at the shaft height, but that the gears must run through the oil and I'm sure splash it around pretty good.

so are there seals on those shafts? Can they be replaced without a tear down? Discussion is appreciated. The oil level is between the marks on the dip stick when held against the dipstick hole. that is to say, with the dip stick not screwed in.

[Jon Pegler]

There are no seals as such on the shafts near the final drive sprocket.
They rely on sealed bearings fitted into the case during initial assembly, so any serious leak requires the cases being split.
The clutch pushrod passes through a rubber seal, held in with a washer, which has part of the case peened over to hold it in place. This seal is fitted from the outside, unlike the shafts.
Nigel Lacey does a proper oil seal conversion that fits in place of the original flat washer if it's past it's best.

[MotoMike]

Thanks Jon

I looked at the seal conversion on Nigel's site. the write up makes it sound like it is for the Narrow case only. Then when looking at the replacement seal some mention is made of needing to bore the WC hole to fit the seal. Not sure if they mean you then use the seal with the original washer staked in over it of if you must bore it to fit the conversion. I guess I need to pester Nigel with yet another of my emails.

I will pull that cover in the next day or so and see if I can tell just where it is leaking and why.

[Teckhardt]

When I took my side cover off to remove the c/s sprocket, I noticed the same thing. Small bit of fresh oil. I did a bit of research cause it seemed strange to me that there was not a seal of some sort . Sure enough, the only thing that holds oil is the bearing shield. Some have recommended going to a rubber sealed bearing (2RS) in that spot if you rebuild (some say remove the inside rubber seal others do not).

I also discovered that original sprockets have a reverse thread on the shaft to act as a oil slinger. The one I removed did not have that. When I ordered my new 428 sprockets from Nigel @ Lacey, he gave me the option of with or w/o the thread. I got it with. Figured it could not hurt.

Curious to hear if there are "mods" to help with oil sealing in this area.

[MotoMike]

Things that occur to me:
My oil level is too high. I seem to recall that the drill in one of my books says to hold the dipstick against it's opening to measure level. If that is not correct, I could be on the high side of my oil level.

I have excessive blow by: The bike has good compression and when up against TDC, it offers substantial resistance to my not insignificant weight. but I did notice that the oil is getting dark already. I thought I would do a short oil change just to get rid of what ever I didn't get rid of on the first oil change to get it running again now that I have been stirring up the sumps contents.

the bike is 41 years old: The seal at the clutch push rod has a right to leak a bit and what little sealing allowed by the bearing shields might have deteriorated. I don't know what the bearing shields are composed of so don't know if this is off base.

That I need to install a valve in the crankcase breather line as Bob had suggested earlier. a mean negative pressure in the cases would tend to keep more oil inside.

More discussion on these and points I have not considered is appreciated.

Hey, If I can get it to run onto the chain, I could have a self oiler

Mike

[wcorey]

I doubt reading to dip stick incorrectly would bring the oil level high enough to be the only cause of your problem, sounds like a PCV would be a good idea.

I can't imagine why they would specify a shielded bearing, it should definitely be a sealed unit. <Edit> Just to clarify, I'm referring to the countershaft/sprocket bearing. The right side mainshaft bearing wouldn't matter as much as there is already the separate seal for the pushrod, a redundant seal on the bearing wouldn't hurt though. <Edit>
A shielded bearing is exactly what it's called and is not sealed, it only has a (usually) metal washer/ring that protects somewhat from external debris but still has a small gap and is not in any way liquid tight. If there is any debate it would be whether to leave or remove the seal on the inner side. Leaving it would give you an extra amount of protection from oil getting through but then you depend on the original grease in the bearing for it's entire life. Whereas with the inner seal removed it gets fresh oil but is also exposed to whatever else is floating around in the crankcase.
I've got into my 450 motor recently and that (double sealed) bearing is the only one that still feels as good as new, I'm very tempted to just remove the seal and repack it and put the seal back. I've replaced all the other crank and trans bearings already.
I may also do a conversion to a conventional seal on the clutch push rod, seems like it would be an obvious improvement. Would like to do something on the timing cover/crank interface too...

[Bevel bob]

I did not suffer any significant oil leak before my rebuild, i removed the simple washer/shield and replaced it with a single seal bearing and installed the Lacey rod seal. I now have a serious leak!!, I suspect the bearing seal and think it was a mistake to leave out the old shield,I would consider a greased double shielded bearing.Dark oil is a pointer to a rich mixture making too much carbon.

[MotoMike]

Dark oil is a pointer to a rich mixture making too much carbon.

I am running too rich in the middle to open throttle position. . I have a rebuild kit on order with leaner jets. In exchangine posts with Nigel, he advises the Amals are terrible at wearing the needle jet and rich running is the upshot. I have no idea when it was last rebuilt, but it is a pre 68 concentric. Got the low speed circuit dialed in now as I have no popping at the near closed throttle position. I can lately kick it over cold with a tickle or hot without and it will start at an idle and run fairly smooth. but a read of my plug still shows a rich conditon. Doesn't smoke that I can tell.

[MotoMike]

How deep is the clutch in the oil? Is it the clutch spinning through the oil that lubricates the gear box by slinging oil all over the parts there in? Or does the gear box gears run though an oil bath as well? Wondered about the Oil fill tube on my 450. It's design makes me think they at some point said, hey we should have put more oil volume in this motor. and then intalled the extender to get more depth in the sump.

[Teckhardt]

I can't imagine why they would specify a shielded bearing, it should definitely be a sealed unit.

Agreed. It may very well not be shielded. I am only going by advice and that I can only see what appears to be a bearing with a shield. After I looked at the parts diagram, there appears to be a spacer washer in there as well that may be giving the appearance of a bearing shield.

Wondered about the Oil fill tube on my 450. It's design makes me think they at some point said, hey we should have put more oil volume in this motor. and then intalled the extender to get more depth in the sump.

My guess is that the extender has more to do with getting around the kickstand rather than any added volume. If you look at the marks on the dipstick, the level appears to be below coming up into the extender.