Valve Ramblings

[CMDRDAVE]

These are just a few things that I was thinking about while working on the valves on my M900.  20K miles, last adjustment was done by the dealer at 14k.

1. Why such a difference between the Ducati clearance spec and the "preferred"  specs put out by various other sources?

2. Does it really make that much of a difference?  I am adjusting to the preferred specs while I am in there, just asking.

3. I would have thought that between 14k to 20K there would not be a lot of change in valve clearances.  But openers varied between 0.001 and 0.003.  Closers varied between 0.004 and 0.011.

4. 3 out of 4 valves had broken collets (OEM).  I know broken collets are not unusual, but 3 out of 4?  From sloppy clearances?  The only intact one came off of the least out of spec closer.

5.  Good dealers will adjust to the preferred specs, but to all/most dealers do this?  #3 and #4 make me wonder if the dealer only checked the valves last time and only adjusted if out of the Ducati spec.

Thanks,
-Dave

[Mr Earl]

Well, I'll take a shot:

1.  From what I understand, the "preferred" clearance values used to be the official Ducati specs.  To facilitate a more "liberal" service interval, the looser specs were authorized.

2.  Yes, IME it makes a huge difference.  Like yours, my bike's clearances after a dealer "adjustment" were way off (but within official limits).  After setting them up to preferred clearances, the difference in running was huge.  It purred.

3.  If the dealer didn't pay attention to the collets' orientation, they were probably installed upside-down or even traded between valve stems.  Then they developed additional clearance as they were re-peened by the shims.

4.  No idea on this - in 4 valve adjustments I haven't had a broken collet - yet.

5.  Again, not sue about all dealers.  But my dealer experiences have convinced me to buy the tools I need and do ALL work myself.

[CMDRDAVE]

Thanks, that all make sense.

Well, I'll take a shot:
3.  If the dealer didn't pay attention to the collets' orientation, they were probably installed upside-down or even traded between valve stems.  Then they developed additional clearance as they were re-peened by the shims.

I went back through the invoice from the last service line by line and found "Replaced all valve retainers/half rings".  So that is probably part of the problem there.  Basically I am going to have to replace them all again.

[♣ McKraut ♣]

3/4 broken collets in 6k miles?  that sounds unsatisfactory to me...

[ducpainter]

Loose closers promote broken half rings.

[EEL]

2) +1 I adjusted mine to 0 tolerance a few weeks ago and it definitely makes a difference. Runs a lot smoother. The biggest difference I could tell was less vibration. I could feel the difference thru my footpegs

3) Your closers are jacked up. They really should be no looser than .001.

4) +1 Said another way, preferred clearance also promotes broken half rings. I had 2 break at my 14k. The problem you have now is replacing the half rings will screw with you clearance again because they will deform and make the closers loose again. It is better that you buy some MBP Retainers IMHO. EMS Duc sells them. This is compounded  by the fact that ducati closers tend to mushroom/deform a bit themselves hence adding to the slop. EMS shims are better at preventing this too.

5) I'm almost posiive that your dealer didnt do your closers like he should have. Between 14 & 20k your bike most likely didnt change that significantly.

[Armor]

I check/adjust valves every winter.  Last winter (20,000 miles) I had to adjust 2 openers and 2 closers.  The biggest change since the bike was new.  I did alot of aggresive ridding last summer which may have caused some of this.