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Discussion Starter #1 (Edited)
I tried the search function,but really didn't get the answer i was looking for.
I'm in the process of shimming my 900 and my 944.Went to the nearest duc dealer (1 1/2 hour away) and didn't take enough time.I have a closer that is .015" too big.Arrgh! Having never sanded them down on a plate of glass with wet paper before.Is this a futile thing to even try? And will it effect the hardening of the closer material?
And....why the f**k are closer shims $29 in Canada,and $9.50 from EMS?:eek:
 

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I tried the search function,but really didn't get the answer i was looking for.
I'm in the process of shimming my 900 and my 944.Went to the nearest duc dealer (1 1/2 hour away) and didn't take enough time.I have a closer that is .015" too big.Arrgh! Having never sanded them down on a plate of glass with wet paper before.Is this a futile thing to even try? And will it effect the hardening of the closer material?
And....why the f**k are closer shims $29 in Canada,and $9.50 from EMS?:eek:
Ric,
When I did my adjustments on my 999S I aimed for a consistent opening between valves. Because of this I ended sanding down almost all of my closer shims with no problems whatsoever. Just make sure you do it in circular motions, use light pressure (i.e. creep up on the dimension), and measure often with the right shim measuring tool.
 

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Discussion Starter #3
Ric,
When I did my adjustments on my 999S I aimed for a consistent opening between valves. Because of this I ended sanding down almost all of my closer shims with no problems whatsoever. Just make sure you do it in circular motions, use light pressure (i.e. creep up on the dimension), and measure often with the right shim measuring tool.
But is fifteen thou a ridiculous amount to attempt to sand off?
 

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Yes it is!

You'll go through the shim's surface hardening in about 3-4 thou.
So find the right size shim or something closer and work it down.
Although adjusting the shim by 0.015" is quite a lot, I'm not convinced that the hardening layer is that shallow. The shims are quite small in cross-section and it is conceivable that entire shim cools down quickly enought during a quenching process making the hardening process quite effective. A case hardening through carburisation may result in a shallow hardened layer but my "sanding" experience does not support this.

I guess this is all rhetorical as I have not asked EMS how they heat treat their shims nor am I willing to section one of my spare shims to investigate.

Anyhoo. :)
 

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EMS shims are made from A2 tool steel and are hardened through, so sanding them down to size will not affect the hardness.

Ducati OEM shims are not as hard, but not sure what heat treat process they have been through. I would say that its ok to sand down OEM shims cause the surface contact area is very large (on the bottom of the shim for closers). The high stress areas on the shim are in the groove where the half rings sit, not on the bottom of the shim. Also the closer shims do not see the wear on the bottom since the rocker arm is simply pushing upward on them. Not like the cam and rocker where you have a sweeping motion and the wear would be much more. I have known people to machine down the OEM shims and they still worked fine.

Concerning cost, we all know ducati charges alot for their parts. How come car belts are so cheap, but Ducati belts are big bucks. Can you say big mark-up? No different for shims.

To remove .015 in. from a shim would take a very long time and your arm would get tired. A few thousanths is no problem.

Mike
 

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No need to cut a shim.....
Just bend a valve and see just how the shim contact surface deforms when it runs into resistance when the valve stops! Practical science.
Hell any experienced Farmboy can spot this a mile away!



Although adjusting the shim by 0.015" is quite a lot, I'm not convinced that the hardening layer is that shallow. The shims are quite small in cross-section and it is conceivable that entire shim cools down quickly enought during a quenching process making the hardening process quite effective. A case hardening through carburisation may result in a shallow hardened layer but my "sanding" experience does not support this.

I guess this is all rhetorical as I have not asked EMS how they heat treat their shims nor am I willing to section one of my spare shims to investigate.

Anyhoo. :)
 

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Shims

Ric: Does the muffin have MBP collets? If so call Guy and ask him to send you the shim{shims } you need and Guy2 will make it right by him. My best, Guy du Poisson, Chevalier du St. Denis
 

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The only real issue is that if your sanding off a lot, you will have difficulty keeping the original flat and parrallel, flat and parrallel. That is, if the shim surface is not kept square, as the shim rotates during operation the valve tightness will accordingly change. If you can somehow measure the thickness around the perimeter of the shim and you can keep it consistent, then no problem.
 
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