I have just replaced the clutch side crank shaft seal on a Sherco 2T.  I have always used an exhaust bung when I wash my bike.  I was wondering if running the engine with an exhaust bung still inserted into the end of the tail pipe would explain the damaged crank shaft seal?

 

         Exhaust bung

Edited April 12, 201610 yr by stpauls

It certainly won't help, the pressure has to escape somewhere. Why would you do that ?

Done it myself a couple of timed by accident. I now use the champagne cork from my previous weekend victory celebrations, this acts as a pressure relief valve, when the exhaust pressure builds the cork pops across the garage forecourt. Apart from a few strangers with a black eyes, no harm done.

As oni says above, my 315 wont start if i've left the exhaust bung in ?   As done it a few times ! 

That's quite an exhaust leak if you can start your Sherco and run it with a bung in? Anne Summers do some very good butt-plugs that would do a much better job....err...I'm told

I've left the bung in by mistake and started it up.Ran badly for a little while and fired the bung into the rose bushes.Scratched my hands retrieving it and learnt a lesson,more careful now

It certainly won't help, the pressure has to escape somewhere. Why would you do that ?

I always warm the engine up after washing the mud off.  I have close neighbours and the bung reduces the volume a lot.  I bet this is what caused the crank shaft seal to fail.

Fair comment, I use a compressor to blow most of the water off, they spray with a moisture displacer. 

 

_{I'm staggered you got it to start with it in?}

Given the pressures the crank seals are designed to hold at full chat I would expect the bung to be forced out before the seals would fail.

Just hold a bit rag lightly over the exhaust if you want to quieten it for the neighbours while running for a short period.

Edited January 31, 201610 yr by 2stroke4stroke

Do you hammer it in or something?