Whats this bolt for?

[UK-GT]

I had a small oil leak and I traced it to this Chrome bolt directly under the pickup cover so I took it out to see what was behind it, I am none the wiser apart from that it should have had a 'O' ring or rubber washer and it did not, hence the leak, I tried to find something to use until I can get the proper 'O' ring but I could not find anything, so I had to resort to instant gasket.

Any ideas?

[Steve]

Can't say for sure, but I think it's a plug in the oil galley.

.

[tatu]

If there is a spring inside that and it moves then its a pressure relief valve.

[UK-GT]

If there is a spring inside that and it moves then its a pressure relief valve.

No spring. I managed to find it listed on the parts fiche (item 24), it says its for the oil gallery pin, but whats it for??

[tom203]

That's an interesting bolt gizmo- fortunately my 650 doesn't have one and apparently doesn't need one! mine has a solid metal plug driven in flush with crankcase surface.

[UK-GT]

That's an interesting bolt gizmo- fortunately my 650 doesn't have one and apparently doesn't need one! mine has a solid metal plug driven in flush with crankcase surface.

That is what my spare engine is like as well, just a metal (looks like brass) plug that is flush with the surface.

[tatu]

No spring. I managed to find it listed on the parts fiche (item 24), it says its for the oil gallery pin, but whats it for??

That's me out of ideas sorry, seems odd that there would be a double seal arrangement.

[Guest]

Put a new o-ring on and reinstall it and forgetboutit

[tom203]

Put a new o-ring on and reinstall it and forgetboutit

No way, I gots to know what it's there for and why none for me!

[koolaid_kid]

Order and install 0-ring 25. No more leak, no more wondering.

[UK-GT]

No way, I gots to know what it's there for and why none for me!

As they say, lifes too short to worry. But they also say, the devils in the detail. But I think the saying that describes this the best, curiosity killed the cat!!
I am in the process of ordering the O ring but I need to sort out my clutch first (33year old springs).
I have done a search on the web but I can not find out what this 'gallery pin' is for and why some engines have it plugged and some do not.

I really want to get to the bottom of this, I hate starting something and drawing a blank.

I will try and keep this thread alive until I get an answer!!

[tom203]

I wonder if the fancy bolt is on early models (or vice versa) and then got added/eliminated later on- maybe engine designer contemplated oil cooler, but later decided it was overkill .

[UK-GT]

Can you work out the year of the engine from its serial number?

[BigD_83]

I wonder if the fancy bolt is on early models (or vice versa) and then got added/eliminated later on- maybe engine designer contemplated oil cooler, but later decided it was overkill .

The 650M (shaft drive baby kats) had oil coolers, didn't they?