Valve clearance question

[Kiwirider]

Ok so I know belts and valve clearance are covered in massive detail all over the forum BUT I have a couple of questions I couldnt trawl up the answer to.
So;
I'm going to do my valves clearances shortly- common wisdom seems to be replace the standard collets regardless. My understanding is this closes up the closer clearance by about 1-2 thou of an inch as the old ones tend to compress/ hammer slightly out of shape. Is this correct and do they really need to be replaced each time?
Does that mean that I'll have to do the clearances again sooner then I would otherwise if I left old collets in?
With regards to the MBP collets, most folks say they are only worth going to if its a track bike, but surely less wear means less requirement to removes shim stacks to a just clearances = less work??

I'd appreciate some feedback from those who've been down this route before

[DME3]

Why would you replace the collets if you're still within your clearances?

[Joe-B]

Yes, new collets will take up about .001". They will loosen up. Old ones become work hardened and are probably OK to use. However, I'll attach a pic of the 3 broken ones I found during my last valve adjustment. I went with MBP collets, which I highly recommend. However, this is on my track bike. On my street bike, that doesn't do tons of miles, I'll stick to the stock collets. The MBP collets are beautifully made and I found them easier to install than the stock ones. They are supposed to extend the valve adjustments to 12,000 miles. I found that they take up .002" or a bit more, so you may have to re-shim (or sand) the closers if they are too tight.

[Desmo_Demon]

I bought my ST2 new and did the valves at 6k, 12k, 24k, 36k, and 48k (once the valves settle in, you can get away with only messing with the valves every 12k). I never saw a broken OEM half-ring retainer and only changed one set trying to ever so slightly change the tolerance on a closer. The 2V engines pretty much aren't an issue and, personaly, I wouldn't waste the time and money for the "upgrade" on a street ridden bike.

[Kiwirider]

Thanks for the input guys.

I know the closer clearances are nearing the maximum factory specs which are pretty generous so I'm thinking the collets may be a bit hammered.

[ducatimike]

The 8 mm MBP retainers tighten up the clearances just a tad, like the others have said regardless of the which closer shims are used (Ducati OEM or EMS).

The 7 mm MBP retainers can tighten up much more. It depends on the shims used. Ducati OEM closer shims tend to tighten the clearances much more than the EMS closer shims. The reason is due to the tighter fit of the 7 mm MBP retainers and slight variation from retainer to retainer.

Mike

[Kiwirider]

Thanks Mike
so you reckon using the mbpdvrs will close up the closer clearance on the 7mm valves? (This is a 1000ds motor)

Given that the oem retainers "settle in" by about a thou or two, would you expect something similar on the MPB collets or is part of their benefit that they stay constant?

cheers

[ducatimike]

Yes, the 7 mm MBP retainers will close up the closer clearances usually from 1 to 3 shim sizes, depending on which closer shims are used (Ducati OEM new shims, or Ducati OEM old shims, or EMS shims) When the MBP retainers are used, the valve clearances dont change as much with time as the stock half rings. You see more adavantage of using the MBP retainers the harder the bike is run. They were initially designed because race bike motors were destroying the OEM half rings.

In the newer bikes, Ducati has changed the shims to a harder material and clearances between the half rings and valve stem and closer shim are also tighter. It can make it difficult to remove the closer shims, cause they get stuck on.

Mike

[Kiwirider]

Brilliant - Thanks Mike