Shimming the Clown Car

As a habit when i acquire another ducati pretty much the first thing that gets done is checking the valvetrain shimming and cam timing. Since this one was bought in Feb last year it was put off for the summer/fall while I rode it about 8000 miles (started at 1700). That being said this is a winter project. The valvetrain was poorly shimmed from the factory so at 9700 miles there was an out of spec closer (loose) and an out of spec intake opener tight at 0.003 inch. Of the 16 closers on the bike 14 were 2.85 mm. The closer clearance on the valves with the 2.85's varied from 0.003 to 0.009 inch. So I'm thinking it was assembled on a friday afternoon after a few vino's at lunch. And the rear exhaust cam was 8 degrees out of time (advanced). Fine job.
I have a lot of 7mm valve shims, early desmoquattro (slightly lower range) and 2 testaretta sets. Normally the approach is spin the cylinder up to TDC. Measure clearances. Take cams out measure shims from motor and then go thru the appropriate shim bunch measuring to find the perfect one (any given shim size will vary as much as plus or minus 0.001 inch). Put the appropriate shims in motor, check work move to next cylinder. Man was I spoiled. Since there are no shim sets available instead the entire valvetrain was measured, cams removed, every shim from all valves were removed, measured and put in it's own appropriate cubby a posted with the size. Then I laid out a grid and figured out what shim from here should go to there. What a PIA. Regardless 14 shims were needed to put the clearances where I wanted, 4 openers and 10 closers (to correct the 2.85 BS). Shims were ordered ($280) and took 5 weeks to get here from Italy. Unfortunately, 3 of the closers were defective. One, an alleged 3.00 mm was actually a 2.80, one the bore where the opener sits was too tight and one where the face of the collet bore and the closer face are out of plane to each other. Took me awhile to figure out what was wrong with that one. I sized a hardroll and spun it in the opener bore of the one that was too tight so I could use it, the other 2 were useless.
In the end all the intake openers are 0.004 inch, exhaust openers 0.005 to 0.006 inch, all closers are 0.002 to .003 inch except two, because I didn't want to wait another 5 weeks, are 0.004, 0.0045. These are on the back left cylinder exhaust valves that are easy to get (relatively) at and change.
Cams were timed (precisely) with the intakes closing at 46.5 degrees and the exhausts to factory exhaust opening of 56 degrees. All in all between disassembling the entire motorcycle, you have to pull the front frame to get at the front head and the subframe to get to the back head, shimming the valvetrain, timing the cams and reassembly about 40 hours. This does not include the time I spent building fixtures to use to time the cams (ducati service tools for this over $1000).

In my experience, I have never seen it this bad.
However, I have found that the half rings that hold the shims break. That was already the case with the 1299. However, it's worse with the V4.
When the half rings are replaced, the tolerance often fits again.

Yep a little worst than any twin I've had. The 1103 V4's use steel collets instead of half rings. I looked at them all no signs of degradation at all. The R collets are titanium. Half rings break from way loose closers. And lose openers pound the rockers (particularly the chromed ones). The rockers are now nitrided instead of chromed so the tool steel cams are now sacrificial to the rockers.

baggerman said:

The 1103 V4's use steel collets instead of half rings.

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And in my experience they break as well.

More broken than undamaged

Wow I did not have a single collet traumatized. How many miles?

Sounds like a chore. No wonder most of these bikes get sold before the desmo service. That is if the engines doesn’t let go before then…

And so many members here champion the ease of service on these bikes

That was a V4 2018. 12.5 k miles. 2 years ago.

I don't think it's any harder than, for example, an R1 RN65.
Even the chain tensioner is such fun on these bikes

bu2tler said:

And in my experience they break as well.

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You know the R's run titanium collets. I thot this was for weight but it must be for ductility. The R's call the closer minimum to be 0.0015 inch. If you're breaking the steel ones I'd try a set and run the clearance way down. I'm doubly happy now that I set the closers tighter. I was thinking about taking the closer springs off to see if I could run them at 0.001 but I was too lazy. BTW my rev limiter is set at 13,500 I wonder if that stopped the breakage of the collets.

bu2tler said:

I don't think it's any harder than, for example, an R1 RN65.
Even the chain tensioner is such fun on these bikes

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Cam tensioners should have a locking grub screw.

bu2tler said:

I don't think it's any harder than, for example, an R1 RN65.
Even the chain tensioner is such fun on these bikes

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Did you have to remove the engine from the frame for the R1?

I’ve done a few Triumphs and it was easy as. Everything was accessible and tools and shims readily available. Ducati seem to make the tools and matériels difficult to procure

The desmo design has it's issues, sliding friction and the valvetrains need to be precisely set up to ensure longevity. Valve spring motors are always easier to shim. And slower due to more internal friction. To do these you would only need one service tool and that would be the one that bolts onto the cams to define the lobe centers. When I assembled the cam drive I did it like the manual suggests centering the pulleys in the slots. I did this precisely (as I was curious about the accuracy) by cutting of the heads of appropriate sized bolts and using drills on either side to precisely center the slot then clamped one of the other pulley bolts down. Then after I did that, indicated TDC in, set up the indicator fixture to check the timing a mm up. Almost dead on the factory timing specs (within a half degree). The factory calls for the crank to be locked with number four at TDC while you set up the timing by taking the alternator cover off and then some other stuff so you can insert a pin. Ridiculous. I indicated TDC number 4 in. and marked the end of the crank and case under the little access window on the alternator cover.

Do you guys know if the closing shims have a heat treatment? I am tempted to precisely grind them down.
I need thin shims that are not offered on the ems shim kit and the 5 weeks shipping time from Italy is super frustrating.