MBP Ducati 4V collet installation   



This document was created in helping those of us who are tired of paying for costly valve adjustments every 3000 to 6000 miles. While your in there do take the time to replace the opening rocker arms so you don't have to deal with the flaking rocker issue. With the installation of these collets, you should be able to get away with valve adjustments at a much greater interval. From what I can tell from the installation, these collets are very well made, tolerance is very tight, and there is no play with the closing shim and opening shim. Check out www.mbpducati.com web site to see what I'm talking about. These collets are only about $300 which would be about the cost of a valve adjustment. Guy from MBP has been very helpful in giving me advice and support in the installation process of these collets. If you are stuck, give him a call.

Tools needed
4v end mill from mbp, lathe with 3 jaw chuck or a self centering vice from MBP, drift,hammer,micrometer,screw driver, wooden stick for keeping the closer rockers open, pliers, electrical tape, some beer, and time.

Actually this is just an overview and tips on how to install the collets. I will assume you already know how to install the collets and do a simple valve adjustment. Furthermore, it would be advisable for you to remove the heads from your bike before proceeding. It's fairly hard to install these collets properly with the heads on the bike.. Well atleast for me. And you know what else, while you're at it you may as well go ahead and replace them rocker arms while you're in there. Flaking rocker arms sucks ass. www.bcmducati.com or megacycle.com can source you these babies but at a price!


From the picture above, you simply need to wrap the collets around the valve stem. There will be a slight gap. To get them to hug tightly just use a large needle nose plier with electrical tape wrapped around it to prevent damage. Just squeeze and it'll be fairly tight but will still have a small gap.


Here is another picture from above.




From the picture above just slide the collets onto the valve and squeeze them together as mentioned before.. Or you can use a drift and hit it from the side lightly..



Now release the closer rocker arms and the spring tension should push the MBP collets into the closer shims. However as you will notice from the pictures above the collets are not fully seated into the closing shims.. (aren't those megacycle rocker arms pretty?)


Now place a drift over the closer rocker arm.. Make sure you have it at 90 degrees as shown and with a hammer give it a good whack.. Make sure you are using an aluminum drift or something soft.

After you hit it a good couple times they should be fully seated as shown. The top of the valve stem should protrude just slightly above the closer shim. Make very certain the collets are seated because your valve clearance could be off by thousands. Now install your cams and put things back in place. Put the cams at top dead center and take your valve clearence for the closers. If it's off you'll need to take things apart and do this over again with a different size shim. All I did was start with a smaller closer (if its a new installation.) Put things together and take the measurement by pushing the closers down and measuring the gap with the cams at top dead center between the rocker and the closer shim.
If the measurements are off, record the clearance I'll call x. Y is define as the size of the current closer shim. C will be defined as the desired gap which is 0.02mm. Finally z is the final shim size desired.
y-x+C=z.
After you've found the desired size put the new collet in as described earlier. You'll need to make measurements again. If they seem a bit tight (rotating the cams gives a certain drag) try taping the closers a little harder to seat the collets. Then take the measurement again. You should have more clearance.. If not try reseating the MBP collets by removing them and reinstalling. Now repeat for the other 7 and always double check your work and double check measurements and clearance. Remember if the collets are not fully seated then your clearance could increase as you break in your new collets over time. So make sure you tap the little buggers in tightly.



Now for the openers.. This part gets a lot easier. First you'll need the special 4v end mill that can be had from MBP ducati for about $75.



As you will notice from the picture, this shim has already been modified. This is how it should look.. I don't know if you can tell but this is how an oem ducati shim looks like. I found recently that the vee-two shims are much harder and seems a bit better produced then oem. Also veetwo shims are cheaper then oem. So use veetwo products if possible. I believe bcm ducati or super moto carries the shim.
Anyway what you want to do is cut the shims down, clean it well, then install them. Make certain that you tap these collets in as they wrap over the MBP collets. Tap them in tight or else your measurements will be off. Install the cams and bring to TDC (top dead center.) Take your measurement (we'll call this y again). Now x is the size of the shim. C=desired gap which is 0.04mm max. z will be the desired shim size. So the formula is
x-y+C=z.

After you obtained your desired shim, install it into your lathe and cut it with the endmill as shown. If you don't have a lathe then make sure you purchase a centering vice from MBP ducati and then you can use a drill press or just get a lathe from www.taigtools.com. I think the setup only cost around $400 or so, well worth the money. Make sure you cut all the way in as far as you can go. The endmill is designed to stop cutting at a certain point (when it reaches the inside of the shims.)

Install them into your bike. Make sure they are fully seated.. Make double sure. Triple check. Now install the cams and bring to tdc. Take your measurement.. This should be good around 0.04mm.. I put mine at 0.04mm or 0.03mm.

Ahh all done with the installation. Troublesome but well worth it as this maybe the last time I have to do valve adjustments for a very very long time. And knowing the clearance isn't floating around and also my rockers aren't flaking gives me some peace of mind. If you haven't already done so, order yourself a set of these collets, you won't regret it. Also give Bruce and Susie a call at BCM for a set of rockers before they start flaking on you.

Copyright 2001
All rights are reserved by me.. Feel free to throw some money my way if you want to reproduce anything here.