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K75 Valve lash

nickrides

Nick Kennedy
Hi Gents
Over a long period of time do the valve gaps tend to open up or tighten up?
I mean like over 40k or so miles.
And is it different for the intake and exhaust?
Thanks in advance!
 
On K75s the valve settings are very stable. My '86 took one shim at 600 miles and not another until 60,000. Then one about 100,000 and one at 200,000 or so. When the bike died in a crash at 369,000 it still had one original shim from the factory.

One reason is offsetting wear. As valve seats and valve heads wear the gaps will close. But as cam lobes and shims wear the gaps will open. Eventually, usually at very high mileage valve head wear overcomes other types and a valve job is needed. The ones I know about happened with 400,000 or more miles.
 
Paul
Thanks for the response
My 1990 K75RT valves seem to be very stable over the last 30,000 miles.
All were perfect at the last check.
Very slightly tight on the intakes, .001 and very slightly loose on the exhausts .001
 
Rules: If valves tighten up, your are doing a valve job because the valve is either stretched or the seat is worn.

If the valves are loose, you are looking at worn camshaft followers as you won't see worn lobes at valve adjust. Sometimes it's worn rockers.

But, my buddy has another 20K miles on his K75 since I first found a slightly tight exhaust valve and three seasons later, it remains slightly tight.

No worries there.
 
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