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Discussion Starter #1
So I decided to do my own valves (helped by the Haynes manual, the LT Snyder book, http://www.ducatisuite.com, http://www.ducatitech.com, the shop manual - yes, I have lots of bed time reading material these days - and the great resource that this board is).
I 'practiced' on the horizontal cylinder first, since it's so easy to access. The measurement of the opener clearance turned out to be very easy and reproducible - the intake opener turned out to be too tight, so I'll get a thinner shim or try to sand the current one down.
I found measuring the closer clearance a little trickier: depending on how hard I pushed down on the closer rocker to measure the loaded gap, I could fit either one gauge (e.g. the 0.102 mm) or the next one (e.g. 0.127 mm) in. Should I go for the largest value (as a worst case, to play safe) or was I pushing too hard on the rocker than is good for me? It's only 25 microns difference but since the spec on the closer clearance is so small, it seems to me that it matters... I guess I could just try to measure the closer clearance directly as a double check (I think I need to get another gauge for that though).
Another question, about Brickwood collets: MBP claims using their collets may extend the check/adjustment interval to 18K miles. However, as I understand it, it only helps the closer shim, it doesn't do anything to the opener clearance, which I assume generally shrinks over time due to wearing of the valve into its seat. Does this mean they claim opener clearance should stay in spec over 18K intervals (I'm at 12K and it seems at least one of my opener shims needs to be replaced...)?
 

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As long as you can easily rotate the closing shim with your fingers, it's good. The old spec, that is condidered better than the new spec, was .000" for the closer. I've installed 2 sets of the MBP collets & while they are a vastly superior product, I don't have enough miles on either bike to verify his claims. This is the 1st I've heard of an opener vs. closer difference with his collets. Contact him dirrectly, he's a nice guy & quite a Ducati enthusiast.
 

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From my observation, opener clearance doesn't change much over time. I've seen crud build up on valve & seat rather than valve sink into head. MBP Collet fixes problem of closing shim adjustments that are caused by OEM wire collets being deformed and work hardened. This has nothing to do with the valve / seat interface.

Do not use largest possible feeler gauge that you can force in when doing closing shim measurements. It is possible to deform rocker arm. Use light to moderate pressure and the largest feeler that goes in without force.

Chris
 

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Discussion Starter #4
Thanks for the suggestions. Tonight I'll have my second valve session (so far I sort of enjoy the whole process...)
 

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i concur. I understand that if everything is adjusted properly with tight tolerances, you can go a long way without and adjust....but they still need to be checked to be sure. You always check them, but you may not need to adjust them.
 

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guess that adds up to less work in the long run! is there such a thing as adjusting the tolerances too much to spec? (i.e. to the point that there is 0.000001 mm margin of error?) - probably wouldn't matter if the other parts are designed with some slop in them.
 

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That's a new one to me Daffy - "too much to spec"!!!
The answer (if you think about it for a minute) is no.
 

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ok thanks... had a conversation with a few local DML-ers about adjusting to spec and for valves, the parts are small enough that the margin for error, or more like margin for no-error, would not be as much an issue.... on larger motors or moving parts that are the size of large SUVs I'm sure that making things too tight will not allow proper movement and make everything seize.
 
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