1098 Desmo, Values

Discussion in '848 / 1098 / 1198' started by Dokus, Aug 12, 2023.

  1. Hello
    I'm doing desmo service myself for the first time on my 1098s and would like to discuss my measurements and thinking with someone more experienced.

    Specs Ducati manual
    Openers 0.10-0.25
    Closers 0.05-0.25

    My values are:

    Horizontal cylinder intake
    Openers 0.10 mm on both
    Closers 0.13 mm and 0.15 mm

    Horizontal cylinder exhaust
    Openers 0.13 mm on both
    Closers 0.08 mm on both

    Vertical cylinder intake
    Openers 0.10 mm on both
    Closers 0.10 mm on both

    Vertical cylinder exhaust
    Openers 0.15 mm on both
    Closers 0.06 mm and 0.08 mm

    Even though everything is within spec to my understanding openers should be at the wider side of what's specific and closers on the smaller side.

    So what I would like to do is to adjust all my 0.10 openers to 0.20-0.25.

    Adjust my closers which is at 0.13 and 0.15 to 0.05-0.10.

    Yes? No? Stupid? Leave it alone? Does adjusting openers have an effect on the closers?
     
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  2. I've just done this job myself and my numbers weren't quite as good as yours. Your exhaust cams on both cylinders are really good.
    I'm leaving mine alone for now but will check again in 5000km.
    Openers are fine at 0.10 but that's as tight as you want. As they are easier to change you could even just rub them back with wet and dry sandpaper to 0.15.
    The closers should be ideally under 0.15 (even better at 0.05) and any bigger gap requires a fatter shim to close the gap.
    It's worth charging them if you can. Be careful with changing closers not to drop the collects into the oil return or the valves into the cylinder (run pistons up to TDC)
     
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  3. Thank you for the quick response.

    So if I read your post correctly, it's enough that I sand the 0.10 down to get 0.15 and leave the closers alone for now?

    I'm planning next desmo service in 10 000 km.
     
  4. My
    Personal opinion yes.
    According to Ducati you can leave all of them as is as they're all within those large clearance margins.
    If you don't have replacement shims you can increase the Openers gap by removing a little. Make sure you use a flat surface.
     
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  5. Thank you Martin. I'll just sand down the 0.10 and leave the rest.
     
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  6. All done with the shims, now all my openers is at least 0.15.

    Another question, camshaft seals, do you guys replace them at every desmo service?

    I've bought the seals and the counter holder tool with socket but the tool was useless and the socket broke at first try so I just kept the old ones in there.

    My seals looks fine, thinking about them being crushed instead of pushed in when the cam gears are still in place.
     
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  7. Wow, some big variation in tolerances there compared to way back, presumably to try to make servicing more 'palatable' cost-wise?

    Almost never need to change any shims with those upper numbers...
     
  8. Yes, big numbers. Anyone got any opinion about camshaft seals? Do you guys replace the every time?
     
  9. I did 3 DESMO services on my 32k mile 1098S and never needed to replace the cam seals. Never saw any oil leakage at all. Just use a sparingly small amount of 3 bond sealant at the places indicated in the 1098 Workshop Manual. Your clearances - top job mate. Well done.
     
  10. Thanks Boggy. Good to hear I'm not the only one not replacing the seals. I rode a couple of hundred miles since the desmo without any leaks. Very expensive if one would replace the seals every time along with the nuts.
     
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