GS550 tappet gap

[delwil123]

Hi all, can anyone give advice, I am checking tappet clearance on my 1979 GS 550 and find that most are 2thou at TDC and i believe ok. However the no 1 cyl at TDC will not accept even a 0.05 feeler, but if i turn the engine till the cam is vertical which Haynes manuel says is another way to check clearance i can insert a no2 feeler into exhaust valve, but still nothing into inlet. It doesn't seem right that feeler guage won;t go in at TDC. Itlooks like i need a smaller shim for inlet, but do you think the exhaust is ok.
Many thanks
DEL
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mickyboy1

[A100man]

Seems slim. Typically exhausts are around 6-8 thou, Inlet 4-6 thou. Make sure you measuring on compression stroke also that you are using imperial feelers and not metric ones.
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[delwil123]

Thanks for reply, yes on compression stroke and imperial feelers. Clearance is in the range of 0.03-0.08mm [ 0.001-0.003 in,] according to Haynes book and youtube. Just strange how i cant get feeler in at TDC but it goes in when cam moved to upright position.
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mickyboy1

[A100man]

[delwil123]

Hi, upright like a pear sitting. Will check if cam caps are torqued, although i have not had them off. Think maybe I should adjust these 2 tappets on no 1 cyl so that i have the correct gap at TDC on compression stroke, and if gap is wider when cam upright i dont suppose that matters as valve is closed.
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mickyboy1

[jeffyjeff]

tappet clearance should be the same at any point on the cam lobe base circle. Apparently, yours is not. As the mfr. specification is stated at top dead center, compression stroke, adjust the clearance accordingly. As you stated, abnormalities at any other point in engine rotation are immaterial, since the valve is closed.
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History shows again and again how nature points out the folly of men - BOC

[delwil123]

many thanks for your input, always nice to have someone else's thoughts.
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mickyboy1

[Pete.]

As jeffyjeff says the clearance should be the same all around the base circle but you know - things wear over 40 year. You don't want the clearance too tight, it'll burn the valves out.

Those GS valves have a very satisfying rustle when they are adjusted right.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good