compression and valve clearance

Norge

New member
Location
Austraila
HI everyone this is my fist post ... I have a new to me 1980 3CL 1000 and from the get-go I had issues with it been very hard to start and not idling
My question is how much does out of spec shims play a roll in compression ? as all 3 cylinders are low
Compression
L / 115 psi
M / 50 psi
R / 90 psi

valve clearance in mm
L / In 0.09 / Ex 0.08
M / In 0.03 / Ex 0.19
R / In 0.03 / Ex 0.13

the right & middle inlet are tighter than 0.03 but that's as far as the feeler gauges goes

as you can see it looks very sad

I'm new to working on Laverda's and need all the help I can get to understand if this is a pulldown or do i do the shims to see if compression comes back into spec.
 
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Vince

Hero member
Where are you in Oz. What is important is what size shims you end up working with. If you end up with very thin shims fixing that gets interesting.
 

sfcpiet

Administrator
Staff member
Location
NRW, Germany
0.002mm? Never seen a feeler guage that thin. Or are we talking inches??

Quite obviously at least 2 valves are not closing properly, no wonder the comp readings are low. Specs are 0.20-0.25 inlet, 0.25-0.30 exhaust.

Restore at least some valve clearance, run the engine for a while to let the valves settle in (remove carbon and/or rust from the seats) a bit and re-adjust to specified clearances, repeat comp test and see where you are. This, and the attained shim sizes, will give you a fair indication of the engines' overall condition.

Be prepared to find a tired old dog, it's all I find these days...

piet
 

Norge

New member
Location
Austraila
0.002mm? Never seen a feeler guage that thin. Or are we talking inches??

Quite obviously at least 2 valves are not closing properly, no wonder the comp readings are low. Specs are 0.20-0.25 inlet, 0.25-0.30 exhaust.

Restore at least some valve clearance, run the engine for a while to let the valves settle in (remove carbon and/or rust from the seats) a bit and re-adjust to specified clearances, repeat comp test and see where you are. This, and the attained shim sizes, will give you a fair indication of the engines' overall condition.

Be prepared to find a tired old dog, it's all I find these days...

piet
Hi Piet,
good pick up on the 0.002 it is in mm the lowest one I had was 0.003 and that would not fit so it is a big guess. where is the best place to buy shims from.
 

redax5

Administrator
Staff member
0.003mm is 3 micron, think you mean 0.03mm
I have 100's of shims in stock, in Brisbane
 

Tippie

Hero member
Location
Dr?bak, Norway
I suspect this is a communication problem. You have measured the valve clearances (which you have called shims) with imperial feeler gauges and the clearance figures are in thou? If so .002" is .05mm, too tight. The compression figures are not good either, was done with throttle fully open? Try a little squirt of oil onto the piston to see if it is rings slipping it past, or do a leak-down test.
 

Norge

New member
Location
Austraila
I suspect this is a communication problem. You have measured the valve clearances (which you have called shims) with imperial feeler gauges and the clearance figures are in thou? If so .002" is .05mm, too tight. The compression figures are not good either, was done with throttle fully open? Try a little squirt of oil onto the piston to see if it is rings slipping it past, or do a leak-down test.
Hi Trppie,
it is a communication issue on my part I was referring to valve clearance they were measured using metric feeler gauges.and throttle wide open for compression test
 

CLEMTOG

Hero member
something is not right here, with Piet on this one, I seriously think that you need some professional help.
CLEM
 

piranha-bro2

Hero member
Location
Melbourne
OK. Very first thing is to get the decimal point in the right place - kinda hard to get our heads around valve clearances when 0.3mm would be just a little too big, but 0.03mm would be WAY too small and 0.003mm is as good as zero when it comes to valve clearances. You sure they're not imperial (ie thou)? All those roods, chains and furlongs get mighty confusing for we of la systeme metrique! 😁

Can you relist your clearances using recognisable figures for which we're all on the same page. Then we can go from there.
 

CLEMTOG

Hero member
I like working in thou and its metric, I mean there are a thousand thou's to an inch, that's metric in my books!

8 thou inlet, 10 thou exhaust, gaps wrong? add/subtract one, two or three thou etc, stuff all those 0.0? and 0.00? I am dyslexic and sticking with it. If it wasn't for those little wriggly red lines I would be stuffed, come to thik of it still am.
CLEM
 
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