2v Valve Shimming

No need for taking the heads off even if you need to change the closers. In that case you just set that cylinder to TDC and stick a screwdriver or a bit of thick electrical cable down the sparkplug hole. That will stop the valve dropping down into the cylinder too far and anyway it's only really an issue with the vertical pot.

Ideally you should remove the belt for the cylinder you're working on, though to be honest I'm not convinced this is really necessary and it's not shown this way in the factory manuals. I don't usually do that unless I'm changing the closer shim and the clearance is near to the absolute minimum. In that case you want to be able to rotate the cam to ensure that it's not binding.

The whole process is straightforward just time consuming. Oh, and don't be surprised that after all your careful measuring and calculating new shim sizes if the clearance isn't exactly what you were expecting! Things like new half rings on the closers etc. all affect the clearance and sometimes it's slightly different just because . . . !

Take your time, read threads in the forum, buy a manual and watch YouTube. Between them you'll get all the info you need.

Have fun!

 

In my experience, the half-rings bed in as much as one full step in the available shim sizes .. which can scupper your calculations.
You can see the witness marks on the end of the half-rings if you look .. very carefully .. with a hand lens.
They bed in one way up and so, if you want to retain your calculated clearances, its best to mark the rings so they can be replaced the same way up.
An alternative is to fit MBP collets which are reckoned to be more stable .. but I haven't tried them myself yet and I'm told they may require complete re-shimming when they are first fitted.

Also, if you're very nifty with a micrometer it is (just) possible to measure the closing shims directly but the radius at the collet location means that this is very tricky.
The easier solution is to buy one of the measuring "buttons" that are available.

Take your time and double check everything, including making certain that the engine turns over with no hint of binding after you've adjusted the clearances ... and if you have reasonable mechanical skills it should be no problem.

Chris Kelly's "Ducatitech" videos are excellent.

 

Completely agree, except for expecting to feel binding by turning the engine over - no chance!
Remove the belts and turn the cams by hand and you will fell the slightest hint of binding.

 

Hi Jody, I do my Hyper evo every 8k miles, though I only dialed the cams in at 32k miles, made a huge difference to ridability, should have done it sooner, took me a while though as I wanted to fully understand it.
Use a good calculation spreadsheet, makes it much easier to understand, I'll send you mine if I can work out how to upload excel doc, or sendme your e-mail address.
Last shim I did all my closers were within 0.1 & all openers within 0.2 of each other.

 

By hand is what I meant but didn't say very clearly

 

Replacing the half rings is probably the first thing that you should do after taking the first set of measurements.
The half rings get hammered really hard and "flatten" out over time because they are round.
The MBP collets are square section and so have a larger surface area to take the applied pressure.
Once the initial bedding has taken place the valve clearances stay in spec far longer

 

MBP Retainers | Product Categories | EMSDUC

 

I've never used the MBP shims but have read a lot of good reports about them.

However, as I think has been mentioned above, I believe that they are incompatible with OEM half rings etc. So you could end up having to swap all the valves to that system or live with having to get odd shims from the US if you only do a couple. That could be a pain in the long run?

 

Personally I'd never re-use them. They have a reasonably hard life and whilst in situe they are unlikely to cause any issues, I have read where they were broken up upon removal.

For a few pence why take the risk? If your clearance on the closer is too loose by a couple of thou then New ring may well take that up. At least till they compress again!

 

I've seen a few where the half rings were broken into 2 or even 3 pieces, usually because the engine has been run with excessive closer clearances. This can also cause the groove in the valve stem to mushroom slightly, making the closer shim difficult to get off unless ease the lip with a piece of emery.

 

Yes, the clearance will decrease by 1 to 2 thou. (0.025 - 0.050mm)

No, the spec is the same although I believe that new old rings will settle fairly quickly to a larger clearance than that set, whereas previously used half rings will have work hardened and the clearance remains as set much longer.

 

This sort of thing is what makes shimming a Ducati as much an art as a science .

Also why your average, vanilla bike shop mechanic (and a few main stealers) will probably screw it up!

That's why I reckon you are better off taking your time and learning how to do it properly yourself, or go to a reputable independent specialist like Louigi Moto (other specialists are available ).

 

Replacing the collets every time you shim the valves is essential. I've often found that you don't need to replace the shims once the collets have been replaced.

Closing and opening shims usually only come in set sizes so you can rub them down to the correct size. I used to measure & record all of them when I took them off and then you can swop them around.
I never removed the belts to do opening or closing shims, I've checked the closing shims by ensuring you can turn them when valves are closed. It's easier to do the shims with the heads removed and that gives you a chance to check the rockers for wear but it's not that difficult to do them in the frame.

 

I prefare shiming the heads on the bench,you can also check the seats while your in there,the half rings dont cost much so relplace them,3 out of 4 on mine were in pieces a result of wear and over reving i was told.

 

What mileage on the bike Jody ?
Post up the clearances before you do any adjustments .... just out of interest of how they settle with mileage on .
I have measured car valve clearances with bucket type cam set up at 100k miles and they are still in spec ..... all engines are different of course

 

One of the potential problems about shimming the valves with the heads still on the bike is that there might be some carbon on the valve seats, which can make the closing clearances seem too tight and the opening ones seem too loose. So if you re-shim the clearances all correct, after further engine running the carbon might burn away leaving the closing clearances too loose and the opening ones too tight. And you don't want that ...