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ST2 shim sizes. Valve clearance.

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Recently bought a 1998 ST2 with 20k Imperial miles on it.
Thought I would start with a full service as it has no recent history.

Checked valve clearances and 3 have closer clearances of around 0.10mm
one has a closer clearance of 0.20mm

I have referred to the Ducati workshop manual and am confused by what it has to say about clearance specifications.

OPENING ROCKER ARM
Inlet:
0.05 - 0.12mm/0.0019 - 0.0047in.
Exhaust:
0.05 - 0.15mm/0.0019 - 0.0059in.
A clearance (A) of up to 0.05mm/ 0.0019in
is permitted: above this clearances
must be reset.

CLOSING ROCKER ARM
Inlet and exhaust:
0.03 - 0.20mm/0.0012-0.0078 in
A clearance (B) of up to 0.20 is permitted; above this
clearances must be reset.

Is there something being lost in translation from the Italian here?

with regards to the opener clearance it states
0.05 - 0.15 mm(exhaust)

but then mentions
"A clearance (A) of up to 0.05mm is permitted: above this clearances must be reset."

This appears to be telling me that up to 0.15mm is acceptable but then appears to say that clearances over 0.05mm must be reset.

Am I missing something here?


Regarding the closers it states
0.03 - 0.20mm and then mentions,
"A clearance (B) of up to 0.20mm is permitted; above this clearances must be reset.

This appears to reiterate that its o.k.to run up to 0.20mm clearances on the closers.

Later, the manual goes on to say that.

"It should be remembered that on Desmodromic valve timing systems any increase in opening clearances will automatically decrease the closing clearances and vice versa.
If you change the opening adjuster you must therefore also change the closing adjuster."

I do not understand how the one can effect the other.
They are opened and closed by different cams. When you check the opening clearance the valve is always going to be closed unless you have less than no closer clearance.
Surely if I reduce the opening clearance with a larger shim it wont effect the clearance clearance between closer rockker and closer cam lobe.

If anyone could shed any light on this issue I would be grateful.
I dont want to put it all back together and then read somewhere that I have done it wrong.
 

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2001 900SSie
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Sorry - read your question again!

I suggest the ST forum section as per this link will be a better place for ST specific questions/answers.

http://www.ducati.ms/forums/forumdisplay.php?f=40

Richard
This question applies to all Ducs, irrespective of model.

Clearances MUST be checked with an absolutely cold engine.

I think the ItaloEnglish info is that this is the range of clearances allowed. If it goes more than 0.05 greater than the 0.15 maximum/preferred (I.e. 0.20), then re-shim to get it back to between 0.05 and 0.15
 

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inlet or exhaust

Hi there
Ok, but what about the exhaust also openers to .004 and closers to .0015?

regards
Arnego2
 
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