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Hi All,

I have read a number of posts related to valve guide seals and understand that there are 2 types: an internal o-ring, or an external cap (mushroom).

I have removed the head from my engine (n°750617) and found an external seal that does not look like the cap (mushroom) type, but a more standard cylindrical automobile type.
It was very hard/stiff and was damaged when removed.

What confuses me is that there is no groove on the guide itself (neither external or internal), so I assume a new replacement valve seal cap (mushroom) will not stay in place. Do I need to replace it with the same cylindrical automobile type? If yes, where would I find the correct one?

Any help would be appreciated.

Thanks,
Christophe

I just found that it is actually identified in the parts book as 0755.92.150 (vs 0603.92.150).

A quick search on the internet and I found this statement on another forum (https://www.ducatiforum.co.uk/threads/a ... parts.594/):

750 VALVE STEM SEALS: D=0755.92.150
The black valve stem seals with the circular springs and firm sides from the first 500 bevel twin motors can be replaced by a General Motors part GM 902 15296. These are a perfect fit on the longer exhaust guide, but need a little bit of sealant on the shorter guide to ensure adhesion.

Any ideas where to find the originals or the GM equivalents?

I ran into the same issue when rebuilding the heads on my 1972 750 GT. Below is the reply I got from Harne at back to Classics in the Netherlands.

These valve guides are original! But only used on the very first 750's so you must have a 1972 engine. The valve stem seals for these are much different an no longer available. So it would indeed make sense to replace them for the later type which do have a recess for the seal to attach to.