[Ducati] 50% Less Maintenance.............

[Ducati5555 at aol.com]

I was also curious about the claims for less maintenance and began to do  
some investigation to see if/what has changed to substantiate that claim.   I 
thought I would investigate the 1098 since it is the new kid on the  block.  I 
went to the Ducati website and pulled up the parts list for the  1098.  I 
thought I would focus just on the valve train, since I have an  interest in that 
part of the bike, and the valve adjustment is the most  laborious of all the 
maintenance.  
 
I found the half rings (retainers)  and opener shims to be the same  exact 
part number as the ones used on the older 4V bikes.  The closer shim  part # was 
similar but off by one number.  So since the half rings are the  same and the 
opener shim is the same then one can conclude that 7 mm dia   valve stems are 
used.  A few months ago I ordered 3 different size  1098 closer shims from 
Italy.  After I received them, I inspected them  and found the ID (inner 
diameter profile) to be the same as the old 4V shims,  but the outer diameter profile 
was  a bit different.   The   start of the chamfer on the outside of the shim 
was moved down on the smaller  sizes.  I have talked to some dealers about 
this and they said the extra  clearance is so the cam adjacent to the valve will 
not interfere as it rotates  around.  Apparently there is not much room as 
the head has become really  narrow.  
 
So there is really no change in the basic design of the closer shim  
retention mechanism as compared to the 916/996/998/999 design (excluding the  later R 
versions of course).   But, I have inspected many  a closer shim and can say 
that the new 1098 closer shims are the  best (in terms of quality) I have seen 
from Ducati.  By good quality I  mean the finish and tight tolerance of the 
bore through the  shim.   I didn't get a chance to measure the hardness of the  
shim.  
 
How does all this relate to maintenance intervals?  Well first of  all there 
are a few areas of wear that cause the valves to need  adjustment.  The first 
area is the where the body of  the valve seats inside the head.  As this 
junction wears in the  valve moves upward and can change the clearances.  Another 
area is the  cam/rocker/shim/valve stem surfaces.  Any wear in these areas will 
 also alter the clearances.  And lastly, and I think most importantly,  is 
the valve groove-retainer-closer shim  junction.  The tighter the  retainer can 
hold the closer shim on the valve stem, the less wear will  occur.  If the 
closer shim is loose, it will bang around and the wear will  be seen in the valve 
clearance increasing.  That is why the MBP retainers  work better than the 
half rings, cause they tend to fixate the closer shim to  the valve stem. 
 
So, all that being said, what has changed in the new design.  Well it  is 
possible that the tolerances on all the parts have been reduced to minimize  the 
movement of the shim on the valve stem.  Also, I have noticed the older  
Ducati shims to wear out where the half ring makes contact with the groove in  the 
closer shim.  A harder shim will reduce the deformation in this  area.  It is 
possible that the shims are harder.  Maybe the half rings  are also harder, as 
I have seen  them flatten out over  time.    All this is speculation but 
could be partly the reason  ducati increased the maintenance intervals. 
 
As someone has previously mentioned,  many of us have found that after  an 
initial break in period, the valves tend to bed in and it seems the need for  
adjustments decreases over time.  I think Ducati has responded to the  gripes 
about the high maintenance of their bikes and extended the intervals  based on 
the same info some of us owners have seen.  
 
So it may be one or both reasons why the intervals were increased.   One 
thing that is important is that not all the parts fit exactly the same in  every 
bike.  Because there are tolerances on all the parts, you will get  some parts 
that fit really tight and so wear is a minimum and some bikes where  the parts 
are on the other end of the tolerance and the parts wear out much  quicker.  
Throw in how the bike is operated (track bike versus street bike)  and you can 
have two bikes respond much differently in their need for valve  adjustments. 
 
>From all this information I think increasing the valve adjustment  intervals 
from 6,000 miles was justified for bikes operated on the street.   I 
personally go 10,000  miles on my ST4 between valve adjustments now that  it is well 
broken in.
 
Mike
94 M944
97,98 916
99 ST4



************************************** See what's free at http://www.aol.com.