I'm doing some long needed TLC to a 1987 K75S with 67,000 miles that includes a good tune-up. Since it's bucket and shims for the valves, I thought a thorough check of clearances was all that was required.
The specs I have for intake clearances is 0.006" to 0.008", a universal intake dimension. Bear with me, I am now comfortable the specs are accurate. I use a 0.006" feeler gauge as my "Go" and the 0.008" as my "no Go"
I get to #1 intake and I'm a "no Go" at 0.006". I'm a "Go" at 0.003" but close to a "no Go" at 0.004" and definitely 0.005" won't go.
This is the intake so I doubt I've got a cupped valve, compression and leak down were great. I'm now concerned I have a pulled stem.
The question: Do I change the shim to gain clearance or do I assume I have a pulled stem?
Next question: Do these engines drop valves?
There are some engines I'd be yanking the head and replacing all the valves if I saw this because I know they drop valves. Camshaft lobes don't grow. Add a moderate amount of wear to the camshaft lobe, maybe 0.001" max without case harden break through, I'm thinking this engine is necking the stem by 0.002".
I feel like I'm gambling with this one and the only place I gamble is Vegas and I know I will loose there most of the time. I don't want to gamble on this one.
Then again, I might be the only person that ever checked and it's been like that from the assembly line...........
Thoughts? They are very much appreciated.