- Joined
- Apr 3, 2023
- Messages
- 1,914
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- Tralfamadore
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).
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).
