Valve Stems and Guides - Lubrication

[Paul Sutton]

When reassembling the valves should I lubricate the stems/guides? I believe the answers is Yes based on the few threads I found. What lubricant should I use? Is engine oil (20/W50) alright to use or should I uses a fine oil like Singer sewing machine oil? I believe greases should not be used because they will leave residues that could make the valves stick.

Thank you for all comments and advice.

 

[5twins]

I just use motor oil. I do have regular assembly lube but it's almost like a light grease or very thick oil. I only use that on the cam lobes.

 

[TwoManyXS1Bs]

Ditto. Engine oil...

 

[Paul Sutton]

Thank you very much 5Twins and TooManyXS1Bs. I should get my new cam chain tomorrow and also the valve grinding paste. It's been 31 Years since I did a topend overhaul on an XS650, but seems like yesterday. Made new 3mm thick brass washers in the weekend to replace those rubber ones. I have done loads of reading so hopefully everything will go smoothly with no major surprises ....

 

[xjwmx]

valve grinding paste

Go easy with the valve grinding. In the factory manual you'll see that the actual contact area with the seat should be only on the order of a mm or so wide. I suppose the issue is the wider, the more likely something is to get under it, or form under it, so that there's no contact at all, I had light pitting but decided to leave them alone.

 

[5twins]

I think it's more like 1.6 to 2mm. I've lapped quite a few, some pretty bad, and never had the seats get too wide.

We're going back into the topend on a buddy's buddy's 650 this weekend. We did it about 8 or 9 years ago when the 1st guy owned it. Now the new owner says it's making a disturbing intermittent ticking, mostly right after starting. It will be interesting to see what we find. This will be the first time I get to check one of my valve lap jobs and also a MikesXS front guide. But, on old bikes like these, really, it could be anything.

 

[Paul Sutton]

Thanks Xjwmx and 5Twins.