748 valve clearance Q
 

Well as I’ve had the old girl a fair while now I’ve decided that it’s about time I tackled the servicing myself, and so far so good, I’m really enjoying myself.
Got all the valve clearances measured today and got to thinking. The online workshop manual shows all clearances .03 tighter than the Haynes book, so pretty close but! As both of these guides are a few years old now have Ducati ever changed the recommendations?
Half a day Googling reveals that almost everybody who’s written about it knows no more about it than I do. If anyone genuinely knows I’m all ears.
Cheers Ian

I had a 748 road bike and several engines in my 996 race bike. I always set both clearances at 0.10mm or 4 thou. It is more important to set the closer clearance first and then the opener. If you try and do both in one go it just won't work.

:)

.10 is a measurement that comes up often and I’ve no doubt it’s widely used and works well. However that reads as out of tolerance with some of the Haynes clearances, both the checking and their adjusting figures. Also with the Ducati figures I have to hand. That is in no way a criticism, just trying to figure out what’s important and what isn’t. If you set at .10 how far would you let them wear before reshiming?
The crux of the matter is if I use Haynes checking clearances I am within spec and need do nothing, if I use any other figures I have varying and differing amounts of shims to change depending on which set of tolerances I’m looking at.:confused: :confused:
Thanks for the reply it all helps me form an understanding.

20 thousand miles on the road bike and 3 years racing 3 engines at up to 11k revs almost all the time. Trust me whatever you have read these settings work.
However if you want to be mega anal about it,


All closers - .05-.10mm

Intake -
open .10-.15mm

Exhaust -
open .15-.20mm


:)

I can’t help myself until I understand :)
Thank you very much once again, i’m sure it’s all a lot more interesting when you haven’t tackled it before .

Something else to consider is how far do you want to go?

Ideally remove the heads and lap all the valves in. This would mean an assembly clearance and then later a checking clearance. You may use new half rings which again means assembly and checking clearances. Even if you re use your half rings they may well settle differently in a new shim therefore requiring another adjustment. :eek:

Deciding on what you want to do is harder than the actual job. LOL

Enjoy

Yes indeed…the thought had crossed my mind. With only two shims and a persistent tiny oil weep from the cam carrier,or rocker pin cover (can’t find it for sure). I’m trying to resist the temptation to find more to do.
Cheers Ian

If you are going to pull the cams out then don't forget to inspect the rockers and particularly the openers for the dreaded flake. :(

Ooo you did have to go and mention rockers didn’t you. Just had a peek…two openers and two closers are just starting let go. Two closers and one opener are original and have covered 40,500 miles. The other is a failed replacement that has done either 23 or 12 thousand miles depending when it went in.
That’ll be my plan for just two shims out the window then, and I all but wished for something else to do, it’s my own fault I suppose:rolleyes: .