Hi
I am trying to restore my 1984 BMW k100 currently in my garage with the drivetrain removed...it all started with the loose grub screw in the gearbox..
The engine hasn't fired for close to three years. I peered inside the exhaust ports (exhaust pipes were removed) and I noticed a white deposit on the valve stems..
It's very difficult to remove and my concern is that the valve stems will destroy the valve guides when I turn the engine. I'm not certain if that section of valve stem passes thru the valve guide.
Any opinions would be appreciated..

Thanks
Gabriel

Hi Gabriel,

The valve guides are 'above' the area you can see through the exhaust ports, so the deposits won't be a problem. ('Above' if the engine were more vertical instead of the K's lying down configuration.)
When you have the valve springs off, you will be able to see if there are any issues with the upper part of the valve stem that might be a problem going 'down' through, but there isn't usually a problem there - perhaps a slightly gummy build up that will make it not just drop out, but need to be gently tapped. More than that, you'll need to remove any deposits to avoid damage to the guides.

With the valve springs removed and the stem in the middle of the normal movement through the guide, you shouldn't be able to rock the valve very far. If so, new guides may be needed. 

Bill