Shim guidance

Schurminater

Schurminater

Hero member
Location
Surrey Hills
So my first technical question guys and girls,I just need a bit of clarity and conformation.

Taking my first look at the valve clearances has given me the following values with A11 Cams.

In:  0.25 - 0.21 - 0.25
Ex: 0.22 - 0.33 - 0.38

Would it be generally be considered right to adjust No 2 Inlet,and No 2 Exhaust as they are very close to the limits?
To me........ No 3 Ex looks a tad big and No 1 Ex looks a tad small.

Whats the general feeling please

thanks in advance

Steve




 
Thanks impala,

I have looked around using the search option and going on that thread and Dellortoman's posting ideally i should be looking at clearances between

0.25 - 0.30 for inlet and 0.30 - 0.35 for exhaust.

Steve
 
I use 0.20 for inlets and 0.35 for exhausts.
Looser is less of a problem than tighter.
Some folk run up to 0.25 inlets and up to 0.30 for the exhausts but I try to keep them closer to the former.
 
And do not torque the cam blocks back down to the green book values - they are too tight and will a) provide you with a tighter shim clearance than you expected, and b) risk stripping studs.
 
Thanks Guys,

Grant thank you, i think that is where my confusion is creeping in and i just need to get a base feeling of what is acceptable limits to allow on Laverdas,I understand that too tight is not so good.

Based on your ideals No 2 inlet would be okay and No 1 & 3 may be too big whereas I was looking the other way as in 1 & 3 were good and 2 was a tad tight?

see what i mean?

I think now i have the measurements I will go ahead and see what shims are fitted and see whats available and go from there,at least they are not too far off the mark  :)

Steve

 
Davo said:
And do not torque the cam blocks back down to the green book values - they are too tight and will a) provide you with a tighter shim clearance than you expected, and b) risk stripping studs.
Click to expand...

Thanks for your cautions Davo,much appreciated,.....i wish the former spanner wielding owner had taken the same advice when fitting the sprocket cover and drain plugs  :-X

Steve
 
Davo said:
And do not torque the cam blocks back down to the green book values - they are too tight and will a) provide you with a tighter shim clearance than you expected, and b) risk stripping studs.
Click to expand...

I've always done the studs to 27 ft/lbs and 20 ft/lbs as described in the latest edition of the Green Book - if head is removed i personally helicoil or similar the centre 8mm stud tappings as it's not so easy to repair if they strip with head and motor in situ.
 
Sorry Phil, my stupidity. Meant the factory workshop manual and not your excellent tome.
 
If valve clearances close up after torqueing the cam bearings, there is something wrong... prossibly the bearings succumbing to the pressure and crushing, especially if the early type bearings are still in use.  Omitting the locating dowels (early heads) or fitting knackered bearings in chewed up guide slots (late heads) will result in ever-differing valve clearances from one cam installation to the next.

Factory spec was 0.20-0.25mm for inlet, 0.25-0.30mm exhaust.  Should be measured with a tensioned timing chain and/or pushing down on the cam while measuring to take up the more-than-generous clearance in many cam bearings.  Differences of up to 0.05mm can occur.

No problem with adjusting to the lower limits, just need more frequent checking.  I use the upper limits for customer bikes, I never know when they may feel the need for the next service.  Very often 3-4 years/20-30K km before I see the bikes again, without the cam cover having been lifted.

piet
 
Thank you Phil and Piet,

you input is most appreciated and your knowledge is a bonus to me as a laverda newbie, all input is of great help and taken on board,

Steve  :)
 
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