shortcut adjusting valve tappet clearance

Specs are:
intake: 0.05mm
exhaust: 0.08mm

Of course the cylinder head also expands when heated, and the valves and
heads are made of different alloys. We would need to know the
difference between the coefficients of thermal expansion. Also the
operating temperatures of the parts and the lengths of the valves.

 

Would everyone agree that it doesn't matter what method is used to
adjust the tappets as long as: after tightening the lock nut, the
specified feeler gauge is a go and the the next bigger one is a no-go?
Also I would want to use this test to decide whether a tappet needs
adjustment in the first place.

 

OK, 0.08mm sounds a lot more credible for the exhaust valves. I was
understanding you to be writing that both intake and exhausts should be
set at 0.05mm...

If I were setting those valves, I would shoot for 0.06 intake cold, and
0.09 exhaust cold. I'm talking about setting the valves less than four
ten-thousandths of an inch loose, for anybody who's *horrified* by the
arrogance of my recommendation...

That way, I'd have a tolerance band of 0.05mm to 0.07mm on the intake,
and 0.08mm to 0.10mm on the exhaust, and I'd adjust the valves by the
Goldilocks Method (GO/NO-GO and Just Right)

I would safety wire 3 feeler gauge blades together, 0.05mm, 0.06mm, and
0.07mm for the intake valves...

When I check for GO/NO-GO, the 0.05mm blade should feel too loose, the
0.07mm blade should feel too tight, and the 0.06mm blade would feel
Just Right after I tighten up that little lock nut.

Just Right feels like pulling a business card out of a thick telephone
book...

Try that and see if the valves clatter too much when the engine's
warm...

Be sure to get that lock nut as tight as you can. The nut and screw are
hardened steel, you can tighten the nut pretty tight...

 

sorry ...

Not exactly horrified: 0.01 mm is equivalent to 1/100 of a turn. I
would be fiddling with it all day. I can't believe anybody adjusts it
that precisely.

 

The first time I set the valves on my GS-1100 using metric feeler
gauges, it took me six hours. I wondered why it was so incredibly
difficult getting those rascals set perfectly, then I realized the tiny
difference between blade thicknesses, plus the lock nuts were pulling
the clearances open when I tightened them, *and* the engine has 4
valves per cylinder and uses forked rocker arms that tilt a little bit
when I tried to slide the blades between the screws and the valve
stems...

 

Yep, my 83 Interceptor has forked arms. The key is to use two gauges,
(tied together with a length of string) It reduces the tilt factor.
The other pain with screw adjusters is that each seems to have it's
own personality. On some, the clearance doesn't change as the nut is
tightened, others incrcrease, or even decrease the gap as it's
tightened.
My fix solution was a new bike (ZX-11) and a set of shims bought cheap
from a closing dealer. Measure once, swap shim, go on to the next.
With screw adjusters, I'd often have to try 4-5 times to get one set
properly.

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