Ideal valve clearance values - Ducati.ms

Ducologist · Jan 13th, 2012, 11:25 am

Well, I think I'm through the learning curve with regard to Ducati valve adjustments. The experience hasn't been hard but has been technical. I just wanted to verify the ideal clearances for an ST2: .100 on openers and .000 on closers? I am just wanting to double check before placing my order.

tonered · Jan 13th, 2012, 11:34 am

I'm not aware of the ST2 clearances, but just a note. If you are trying to nail those specific clearances, they may not come out right on the first go. I usually end up swapping shims a couple times to get where I want to be.

Have a good one.

va duc · Jan 13th, 2012, 1:05 pm

I go with LT's recommendations for my ST2.
Openers @ .1mm (.004")
Closers @ <.05mm (< .002")

DuckMan · Jan 13th, 2012, 1:09 pm

What both these dudes said. LT knows stuff and trying to end up dead on target is a bitch. I'm anal as hell about stuff like this but I'm still sane enough to NOT sand shims if they are not .ooo perfect.

Ducologist · Jan 13th, 2012, 1:35 pm

Quote:

Originally Posted by va duc

I go with LT's recommendations for my ST2.
Openers @ .1mm (.004")
Closers @ <.05mm (< .002")

With the closers is it better to be on the .05 end of the range, or closer to .00?

What would "perfect" be considered with regard to performance?

va duc · Jan 13th, 2012, 1:57 pm

Quote:

Originally Posted by Ducologist

With the closers is it better to be on the .05 end of the range, or closer to .00?

What would "perfect" be considered with regard to performance?

Perfect would be as LT recommends. I am in agreement with Duckman. Given that you can get the shims in .05mm increments I get them as close to spec without sanding the shims, given Ducati's spec at such a wide range you will be close enough. If you get the closer to tight it will cause premature wear and you could bend a valve.
Ducati recommends .03-.20 mm for the closers, so you can see that if you go with .05mm you are very close.

I am no expert, I set them as close as the shims will let me without sanding and ride the piss out of it!
I have also installed the MBP collets as those half rings drove me crazy.

I get all my shims here.
Ducati 2 Valve and 4 Valve Adjustment Shim Kits

Stick · Jan 13th, 2012, 2:16 pm

If you go with closers at ZERO, I believe you run the risk of wearing the cam/closing rocker finishes. Sero would be "ideal", but it would need to be verified throughout the entire revolution of the cam. And, while you're at it, it would need to maintain the proper clearance for the opening rocker for that revolution also. The cam lobes probably aren't accurate enough to get you there.

DuckMan · Jan 13th, 2012, 2:53 pm

Quote:

Originally Posted by Stick

If you go with closers at ZERO, I believe you run the risk of wearing the cam/closing rocker finishes. Sero would be "ideal", but it would need to be verified throughout the entire revolution of the cam. And, while you're at it, it would need to maintain the proper clearance for the opening rocker for that revolution also. The cam lobes probably aren't accurate enough to get you there.

As per LT, zero is when you depress the rocker HARD and can still rotate the shim with your fingers. If you can do this there can be no damage. The clearance increases a the motor warms up.

tonered · Jan 13th, 2012, 4:53 pm

I guess one could say the info gained from LT's manual is well worth the money. Also, a full shim kit from Mike makes it quite a lot easier.

Have a good one.

stryder · Jan 13th, 2012, 6:49 pm

Quote:

Originally Posted by DuckMan

... The clearance increases a the motor warms up.

As steel expands when heated, how do the closer clearances increase? The valve stem gets longer, and takes the closer with it? Is this why the opener gap spec is is wider? It gets tighter as the valve stem expands?