A10 Oil Leak into Primary chain case (belt drive) part 2

[rwbeard]

Hi there,

Firstly many thanks to all of you who responded with help.

The story so far. Oil was getting into the primary chain case, and getting onto the dry Newby Belt drive conversion.

The considered opinion was that oil was coming from the crankshaft main bearing oil seal.
So I set about removing the clutch, only to find the drive pulley nut too hard to remove. So I purchased a Clarke CEW1000 impact wrench for £55, brilliant off in 5 seconds! What a tool.

I have attached photos of what I found which I hope explains the issue visually. The spacer between the crank pinion and the drive pully is too small in diameter (4mm) to purchase against the oil seal, and hence there's nothing to stop oil from the main bearing entering the crankcase, and in flung all over the drive pully.

I will therefore send details to Bob Newby, and see if the previous owner of the bike had been sent and then fitted the wrong spacer.

I will keep you informed as to progress

Bob Beard

[fido]

How could anyone not notice a gap between the seal lip and spacer!  I had a similar problem with my B31 but that does not have a seal, just a flinger to throw the oil back into the crankcase. In my case it turned out to be the main bearing which was loose on the crankshaft and oil was getting though the gap between journal and bearing.

[bsa-bill]

looking at the bottom photo of the spacer - depending how you look at it - one way it seems like it might not have the internal champher, looked at from the other side maybe it does.

Could be the wrong spacer right enough

[mark]

I have a Newby belt drive on my A10 and I'm fairly sure that the inside spacer that comes with the Kit doesn't run inside the oil seal. It sits against the original cush drive distance piece (67 1138) which is what seals. This is what has the internal chamfer that BSA Bill mentioned

Mark

[rwbeard]

Thanks all,

Makes perfect sense now, and verified by Bob Newby as well this morning. There's a spacer missing!

I have ordered part number 67-1138 and so should have the show back on the road very shortly.

Regards

Bob

[rwbeard]

Greetings,

Update. All assembled, and back on the road today - and no leak into the primary drive case.

It's still running in, but for a brief moment took it to 70mph, and was surprised how few vibes there were from the SRM rebuilt engine.

There are a couple of weeps from the oil pipes to the oil tank, but when I change the running in oil to the std SAE40, then I have some dowty washers which should sort that out.

Let the good time roll

Regards

Bob Beard

[muskrat]

Great to hear Bob. With the way it was set up your lucky not to have damaged the belt.
That's a great looking bike you've got there. Time to enjoy.
Cheers

[a10 gf]

Always nice to read good news, & nice when members post solutions. & a great looking bike.