Cylinder Head Shim Problem

pf1

pf1

Hero member
Location
Portsmouth UK
I have just bought a much abused Spanish triple with a cylinder head stamped
980 which I assume means September 1980.

The right hand exhaust shim has disintegrated, the top having completely separated from the flange causing some damage to the valve tip and battering the flange onto the valve.

Are the heads of this period problematic? Is this a known problem? Can I just replace the valve and shim and live happily ever after or is there remedial action which needs to be taken?
I haven't had a chance to examine the head thoroughly but I cant see any obvious cracks or damage.

Any advice would be appreciated.
Cheers Pat.

 
Pat,

Two things to check are:

1. Does the head have the short valve springs?  If so, replace them with standard triple valve springs.  The spring retainers will also need to be replaced. 

2. What is the exhaust valve size?  If 36.4mm instead of the normal 35mm, then this might result in inlet and exhaust valve to valve contact.

Might also be a good idea to check for hairline cracks in the corners of the cam chain tunnel. 

HTH
Tom
 
Thanks for the replies lads, I've been trying to resize some pics, lets see if it worked!
Now this bike got me thinking, isn't this just what the hipsters are trying to reproduce?
It was used to terrorise the good citizens of Malaga in it's day and I quite like it  :D

 

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Looks like an all-alloy head, can of worms imho.

I'd check the thicknesses of the other shims first.  If a shim breaks up, chances are it was ground paper-thin.  The others won't be much different, so a complete overhaul will most probably be on the cards, in which case the correct springs and retainers can be fitted. 

I've yet to see any half-decent Laverda to come out of Spain, most are run into the ground.  Hope for the best, expect the worst...

piet
 
Thanks Piet, I'll have a better look when I go down to Portugal again in a couple of weeks.
The bike is sat down there adding to the general air of neglect.
 
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