CAM TIMING

I thought I'd share this info about cam timing that was in Cycle World magazine, it's from the "guru", Kevin Cameron. Notice that the most important valve timing event is the intake closing point. Also the really small "valve overlap" of only 11 degrees for the new Diavel (and the Multistrada, I believe) for low end grunt.

I hope you find it informative.

Both closing shims installed.

Here a rubber coated blade of a screwdriver is inserted behind the closing rocker arm holding it against the helper spring so that the shim can be installed.

A shim can be made smaller by up to 3 thousands of an inch by carefully sanding.

I take one thou off by sanding on a piece of tempered glass with 400 grit paper and WD40.

Followed with 600 grit.

More can be taken off by starting with 220 grit paper followed with the 400 then 600.

Make sure the shim is held flat and rotate it on the paper occasionally.

BE CAREFUL. THE SHIMS CAN GET VERY HOT WHILE SANDING.

Finish each sanding session with a good cleaning with brake cleaner and compressed air.

This also helps cool the shim before rechecking it.

Write everything down.
I measure in "inches" because it's easier to do the math. But I convert the readings to "mm" to determine the correct shims to get. It's important to take "your" micrometer with you to check the new shims before purchase as they may be labelled incorrectly or checked with a different device.

The top of the shim should be flush with the top of the valve. (R)

You may have to pull up on the bottom of the rocker or snap it a couple of times against the closing spring. This will seat the closing shim.

It’s critical that the keepers are seated correctly!

Keep all the valve train pieces organized.

Makes it much easier on reassembly.

I set up my table with wood head support and feeler gauges.