Hitchcocks Forum

Hi guys,
I am currently in the process of replacing the sprag clutch on my Classic 2010. While waiting for the new part from our host, I have disassmbled the LH cover and removed the old and broken sprag clutch.

My question: when I removed the cover, I detected that there was no gasket, only some kind of silicon. Since I already have bought a complete set of new gaskets from our host, I plan to use a gasket when putting it al together again. Hovever, is it enough with the gasket (possibly wetted with some grease) or should I cover all surfaces (gasket´s both sides and the two mating metal surfaces) with Hylomar or similar? I have studied several threads in this forum as well as other sources, but it would be wrong to say that I get a clear and concise opinion.... I don´t want to glue it all together so that it will be impossible to re-open at some point in time.

What´s your view, what is suitable for a RE UCE engine?

Best regards,
Gunnar

I recently replaced my sprag clutch and primary chain, so bought a gasket prior to doing the job. However, like you, I found that there was no gasket there when I took the cover off.
From what I've seen on the web, it may or may not have a gasket fitted 'as standard' but if it does have a gasket, you need a shim behind the clutch thrust bearing to compensate for it's thickness.
I didn't use the gasket but used clear silicone 'instant gasket' stuff when I replaced the cover.

Frank

Thank´s Frank. About the shim you mention: I haven´t heard of that, can you give me any reference so that I can study this as well, before I move on with the job?

Best regards,
Gunnar

Hi Gunnar, I just found it when I was looking on Youtube for tips on doing the job. It might have been this one: https://www.youtube.com/watch?v=ruVBmQx4Adw but it might have been another?
My bike had no gasket and no shim so I put it back the same way.

Frank

Hi Frank! I´m not sure this was the video you thought about; whilst it was indeed very good and educating, he didn´t mention anything about the necessity of a shim when using a gasket. He in fact also used silicone. I do not quite understand the need of a shim; what is so sensitive that you need to compensate for the millimeter (max) that the cover will be moved outwards?

The "to be or not to be" concerning the gasket is a bit strange really. Neither the Hayes manual nor a original RE manual that I have on PDF actually describes a gasket for the LH cover. In fact the RE manual descibes the usage of a Loctite product instead of a gasket for this particular place. Our host however clearly shows in their excellent online parts catalogue a gasket also for LH cover. But no shim....

I have a new gasket and I have Hylomar M on spray that I will use to dress the gasket with.

Frank, thank you for your feedback anyway!

Best regards,
Gunnar

When using a gasket I tend to use hylomar on one side grease on the other
Many years ago I was taught to use hematite on one side grease on the other

Just want to conclude my own topic; I ended up using Hylomar on both sides of a new gasket. Not a drop leaking! The interesting thing is of course if it will be possible in the future to open up again without too much effort.

Best regards,
Gunnar

I used a gasket that I greased on both sides. I didn’t do any shimming of the clutch because I wasn’t aware I should, not do I see why, given that the clutch free play is adjustable. Result: no leaks, easy removal of chain case next time and no difference to clutch function. I prefer grease to Blue Hylomar because it’s easier to remove and there is less risk of blocking an oil way.

IF your machined surfaces are good there should be no need for any gasket cement. A smear of grease helps the gasket to come off clean next time. If in need of any gasket cement I always use Wellseal. It works well but is a bit of a sod to clean up.