shim measuring

[IanA]

Tried a search and not found an answer, what is the best way to measure the valve shims please

[ranton_rambler]

I use a 0-25mm micrometer.
Ian

[IanA]

Apologies i wasn't clear enough in my query. As i understand it they are an inverted cup, do you measure the thickness of just the cap, eg the micrometer goes up inside the shim or the total height of the shim.

[LaceyDucati]

Hello Ian

This is a surprisingly common question/confusion, we have quite a few incorrectly ordered shims for this reason.

The answer is that the quoted shim size is the thickness of the "working" part of the shim in the recess. Therefore you measure the shim with the micrometer in the cap and not the overall thickness.

Regards Nigel

[IanA]

Top man Nigel thanks.

[thebossdj]

I would love to see some of the different micrometers the experts use to measure these. Saw a neat o dial gauge for the shim. It’s always a treat to see specialized tools.

[Samurai]

I've never owned a bevel Desmo, so I may be talking out of my hat, but if they are the similar to the 7 or 8mm shims used on belt drive Ducati's, then there are measuring 'posts' available from a few different sources, a couple shown below:

https://rover.ebay.com/rover/0/0/0?mpre ... 5020951670

https://www.ebay.com/itm/283683012187

These allow the internal lip of a belt-drive closing shim to rest on the 'post', allowing you to more easily measure the total height. You then simply subtract the height of the post from that total and you get the height of the shim itself.

I used to measure them using a small micrometer and getting it to 'latch' onto the internal lip, but I'm sure it's not as accurate, as there is a tendency for the shim to tip slightly if you're not careful and give you a slightly false reading. The measuring tool made this much simpler.

Not sure if the Desmo shims are the same, but I reckon Ducati wouldn't have changed such a basic component over the years if they could help it, the last revision I know of was when they introduced 7mm valves on the Desmoquattro engines and you can get the same measuring tools for them too. I see that the tools are pretty cheap now, so it may be worth a punt to see if they help?

[Jordan]

No arithmetic needed, if you zero the digital caliper on measuring the shim plus tool, then measure just the tool. Readout then gives shim size.
Is there an advantage of the tool over a direct reading micrometer?

[Ventodue]

<snip> Is there an advantage of the tool over a direct reading micrometer?

Was kinda asking meself the same question, Jordan ... Can someone enlighten us, please?

[graeme]

For opening shims, no, a micrometer will do what you need. And good feeler gauges.
Graeme