Ducati.ms - The Ultimate Ducati Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
60 Posts
Discussion Starter #1
I got the bike this spring at 9800 miles and it has 12K now. Motor has never been touched other than oil changes and the belts I put on a few months back. Runs great. I had some apprehension about the lack of valve train maintenance. The horizontal cylinder is towards the loose end but amazingly not out of spec with exhaust closer at .002 and opener at .005. Intake closer .002 and opener at .004. The hotter running vertical cylinder is out of spec but not horribly: roughly 2 -3 thousandths out on all shims.

Newbie impressions of the procedure:
Even Snyder doesn't mention removing both clips so you can rotate the cam to the point where the valve can be depressed and the collets removed. Had to find that technique on a youtube video. Also, I found it handy to have two clamps so the engine can be rotated and both intake and exhaust shims removed simultaneously. Didn't find that tip documented anywhere either. Still have to get shims and reassemble (waiting on measuring tool to mount shims in the micrometer).

Overall I'd much rather shim a Ducati than remove the cams and shim a more conventional valvetrain. Snyder is negative on MPB collets saying they're too hard to install for other than race use but others disagree. Unless I hear otherwise I'll be reusing the stock collets.
 

·
Registered
Joined
·
158 Posts
The stock half rings are just fine. Make sure you install them on the same valve and same side up.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
55 Posts
I found the MBP retainers easier than the stockers personally and I changed them out the first time I'd even seen a desmo valve train in the flesh (It was a long winded affair regardless) but each to their own. Plenty of people running stock retainers with more mileage than me. Probably more the cost of the MBP's that deters people from using them.

Removing a closer shim due to a deformed valve stem, now that is a PITA....

Sent from my SM-G930F using Tapatalk
 

·
Registered
Joined
·
1,605 Posts
I got the bike this spring at 9800 miles and it has 12K now. Motor has never been touched other than oil changes and the belts I put on a few months back. Runs great. I had some apprehension about the lack of valve train maintenance. The horizontal cylinder is towards the loose end but amazingly not out of spec with exhaust closer at .002 and opener at .005. Intake closer .002 and opener at .004. The hotter running vertical cylinder is out of spec but not horribly: roughly 2 -3 thousandths out on all shims.

Newbie impressions of the procedure:
Even Snyder doesn't mention removing both clips so you can rotate the cam to the point where the valve can be depressed and the collets removed. Had to find that technique on a youtube video. Also, I found it handy to have two clamps so the engine can be rotated and both intake and exhaust shims removed simultaneously. Didn't find that tip documented anywhere either. Still have to get shims and reassemble (waiting on measuring tool to mount shims in the micrometer).

Overall I'd much rather shim a Ducati than remove the cams and shim a more conventional valvetrain. Snyder is negative on MPB collets saying they're too hard to install for other than race use but others disagree. Unless I hear otherwise I'll be reusing the stock collets.
Concerning the MBP retainers; EMS licensed the technology from MBP a few years ago. One of the reasons I did this, was because, at the time, some of the retainers fit very tight or did not fit at all, which reflects the experience some had in using them. I really liked the concept of the MBP retainers and product fit well with my product line. In discussing the issue with Guy Martin of MBP, we decided that a complete review of the design and the manufacturing process was needed to fix the problem of variability of the fit of the MBP retainers onto the valve stems and also their fit into the closer shims. Since I have a high end CAD system (MBP did not) and many years experience in the design of high tolerance assemblies, we came to an agreement where I would take over the product's design and manufacture and with the help from MBP.

This review was conducted at the same time the transfer took place. Long story short, I found some discrepancies in the tolerance stack up on all the parts which affected the fit at MMC (maximum material condition). I also found slight deformation occurring with the heat treat process. The fit problems were remedied by redesigning the variation in the cross section of the design, changing the tolerances so interference was avoided at MMC, and using a heat treat process to minimize internal stresses to avoid part deformation.

The result has yielded a very low scrap rate with parts that fit nicely every time.

I receive frequent calls from customers asking if they should purchase the MBP retainers. Here is typically my answer:
The stock half rings used to retain the closing shim onto the valve stem are an adequate design. Ducati would not put them in almost every Ducati made if they did not work properly. That said, there are occasions where the half rings are the weak link. I have many customers that race Ducatis that tell me the stock half rings break during long periods of high rpms (track use), especially if steeper (race) cams are used, which make sense as the acceleration and impact forces increase. Since the MBP retainers are made from A2 Tool steel and hardened, have a larger mass, they are much stronger and last much longer in race conditions than the stock half rings which are made from spring steel and have less mass in their design. This advantage has been verified by many of my racer customers.

So then they ask "well I only use my bike on the street is it worth it to buy them for my bike?" I say another advantage is that the MBP retainers do not deform over time because they are so hard, unlike the half rings which flatten out over time, thus increasing your closer clearances. Also, because there is more surface area in contact with the valve stem, the MBP's are actually easier to install because once engaged in the groove in the valve stem, they don'f flip-flop around but sort of lock into position as they are installed.

The bottom line, they are a better design, easier to install, and do increase valve adjustment intervals, and the stock half rings are adequate. So the decision depends on considering how hard the bike is ridden, the actual process of installing the retaining system, valve adjustment intervals, and cost.

Another bit of info that I have found out is that the half rings do tend to deform (flatten out) at a faster rate when they are first installed then decrease in the rate of deformation as the loading cycles increase. I believe a work hardening process is occurring which actually strengthens the half ring to a point, over time. This info should also be used in determining the purchase of the retainers.
 

·
Registered
Joined
·
60 Posts
Discussion Starter #5
I've finished installing replacement shims and am quite happy EXCEPT for one of the opener shims. Sanded that one down from 5.21 to 5.13. Towards the end I could sand .01 off in a minute or so and that rate was much faster than encountered on other shims. I don't know much about hardening metal and how deep the hardening goes but think I've installed an overly soft opener shim. Should I wait 6 - 10K miles to check clearance again or maybe pull that one out immediately?
 
1 - 5 of 5 Posts
Top