Removing a Primary belt drive

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O Wise Ones!

I have to replace the crankshaft seal on my 72 Commando which obviously necessitates removing the primary drive on this case a Les Emery installed belt drive.

Has anyone done this? What are the dos and donts? Is there a source for info on how to do this somewhere on the interweb?

As ever any guidance gratefully received

Nick

Remove alternator rotor and…

Remove alternator rotor and stator as per chain primary
Remove guide plate on outside of engine pulley and slide belt off
Screw 5/16 UNF bolts from standard engine sprocket puller into engine pulley to a good depth
Tighten the puller centre bolt against the end of the crank until the pulley comes away (heating pulley can help)
Prise out woodruff key
Screw 2 self-tapping screws into case of oil seal and use to draw seal out
Clean away any swarf.
Fit new seal (and new belt if oily)
Reassemble.

Hi Stan Thanks for the clear…

Hi Stan

Thanks for the clear concise information. Much appreciated

Nick

Blow By

Hi Nick,

I would also ask why are you replacing the seal - do you get oil in the primary drive, which is of no use since you are running a Norvil belt drive?

If yes - a new seal may not help, as what is happening is your bike is wet sumping and on start up the oil in the crankcases is pushing past the seal, prior to the oil pump clearing out the excess oil from the crankcases - the same will happen with a new seal, regardless.

Anyway - give it a try - but things may not improve!

Regards - Paul.

Hi Paul Yes the reason I am…

Hi Paul

Yes the reason I am changing the seal is the amount of oil in the primary case due to wet sumping.

In times gone by this was never an issue. As I leave the bike unused for months at a time (it is in France and I only get there 3 times a year), I have taken to draining the oil before leaving. However on one occasion I drained from the sump not the tank and obviously plenty of oil still came down from the tank. Result was enough oil to cause the clutch to slip and the belt was well soaked in oil and plenty came out when I removed the primary cover.

What I am concerned about is that oil will continue to leak into the primary while riding hence the idea to replace it. It seems that the amount of leakage has increased over time so maybe a good idea to replace it. Engine was last rebuilt in early 2000s so it may be time.
I now drain all the oil out of the tank before leaving it standing and refill when I get there. I know that the wet sump issue is there for ever it is just how to manage it I guess.

it would be nice to not have to do it! Is it something I can get away with? Not sure!

Cheers Nick