749S 6mm Valve stems

[He Man]

I recently found out that the 749S has a lot more difference then i originally thought.

im not sure what year it applies to either...if anyone can shed some light on it.


the 749 i am picking up is a 2004 749S. It apparently has 6mm stems and titanium collets...where do I get 6mm collets? Other then the dealer?

what are the valve clearances for the 6mm stems?

[ducpainter]

I'm not aware of any valve stems smaller than 7mm. 

[He Man]

"Engine breathing is boosted by the use of narrower valve stems (6mm from 7mm) and the diameter of the inlet valves has grown 1mm to 38mm to speed up gas flow. And because of this, and the higher rev limit, the valves' closing shims are now retained by conical titanium collets. These are the same type as used in Neil Hodgson's WSB championship winning 999 F03 bike. They are much bigger than the old 'wire' type retainers and have a greater friction effect to effectively grip the valve stem and stay in place at high revs. New camshaft profiles have led to longer valve lift and duration."

from MCN... and also a few members on the ducati.ms board have said the same thing.

thats only for the 2004 and not 2003 749s. i need to make sure what year im buying now....EMS duc doesnt even sell shims that work for 749s or 749r models either.

[ducpainter]

They do list different valves and collets as opposed to split rings for the 04.

No idea if the stems are 6mm or not.

[Speeddog]

For reference:


'04, '05, '06 749S, 749R
'04, '05, '06 999R
1098R

All have 6mm stems and the taper-style collets instead of half rings.
Special tools required for removal and installation I'm told.
Shims *only* available from a dealer.

[He Man]

  Well When i open her up, ill verify which motor it is since its been through several owners. Maybe the frame is an 04 749S, but the motor isnt. i dont know. We'll see.

I just hope those shims dont fetch an ultra premium price.

was there an 03 749s available in the states? The shim chart doesnt list it, but every else does.

[ducpainter]

Well When i open her up, ill verify which motor it is since its been through several owners. Maybe the frame is an 04 749S, but the motor isnt. i dont know. We'll see.

I just hope those shims dont fetch an ultra premium price.

was there an 03 749s available in the states? The shim chart doesnt list it, but every else does.

When I tried to download the pdf for it in US English...

nothing happened.

[devimau]

If I were you the cost of the shims would be the least of my worries....I would worry about those closer's clearances....you don't want to remove the heads to replace the closers shims, do you?

[He Man]

you cant do it with the heads in the engine?

I thought that was a huge benefit to the testa design...

the frame is going to get powder coated, so when i check the valves the motor will be out and about.

[devimau]

If you can pound the retainers out of the shims then no need

[He Man]

Are they as bad as MBP collets? Cause those were a make the beast with two backsing PITA, i used a brass punch and tapped it...forcefully

[devimau]

you seem to have bought the model with the conical collets, they are torqued to 10nm with an special tool and in order to remove them you need to put the head on this special tool that supports the valves so you don't bend them when wacking out the shims from the collets.
Some people say that if you pressurize the cyl and put the piston on btc (so you won't bend the valves when they hit the piston while hitting the closers) it might come apart (never worked for me).
If your motor is apart from the frame then you should put special attention on the closers clearances, the openers are the same than a regular model.
This system was used on rs models and factory bikes only, ncr machines and lately on 999r, 749r, 749s (only some years) and 1098r.
Testa dessing benefit?....only to check the closers, to replace shims is the same that the desmoquattros where the cam has to come out.

[He Man]

well this is a track only bike. so maybe pulling hte heads off once a year isn't so bad and i dont mind doing it over the course of several weeks.

tools though....