Valve Clearances Notes

[Pedro]

Following a couple of requests, here's my notes I wrote up a couple of years ago about setting valve clearances - DIY Stylee!

I would suggest having at least a Haynes Manual handy or even invest in a workshop manual on CD from Fleabay (or ask me nicely.....!) when you do this. Anyfeedback, let me know and I'll enhance the notes.

Ped

[Pugi]

Cheers! :thumbsup:

[Sparky]

Excellent guide ped although I have already done mine, will keep your guide for future reference though.:thumbsup:

Chris

[Shauns4]

Anyfeedback, let me know and I'll enhance the notes.

Ped

never had to change the closing shim, don't you need 3 hands?

Shaun

[Pedro]

never had to change the closing shim, don't you need 3 hands?

Shaun

Agree it's a bit fiddly but I held the valve with a cable tie to stop it dropping a little and that seemed to work fine.

Four valvers may be a little trickier......

Ped

[Shauns4]

Closer on the 4 valver is not so bad once all the gubbins is out of the way as you can lever the rocker down with a screwdriver through the cam shaft hole. Main problem with the 4 valver is access to the rear cylinder exhaust valves, easier to take the engine out, well almost.

[Pedro]

At least two mechanics I've spoken to about 4 valvers is that it's easier to take the heads off - much quicker and quite likely cheaper!

Ped

[Shauns4]

the Haynes 916 manual also says the same!

[eonan]

Pedro thanks for this...really appreciate it. My aim in life is now to give these thieving b*stards as little of my money as possible!

Erm, how nicely would I have to ask you if you have a workshop manual for a '98 750? I can get a 900 one no problem, but the 750 never seems to pop up.

:hail:

[Fosse Foxfight]

Ped, where did you get the values for the clearance from? Are they the ones from the Haynes manual? Or are they the preferred ones as used by all the dudes in the know, ie the original ones befroe Ducati decided to change them for some reason unknown to me?

Sean

[Pedro]

I've got the 900 version - should be albut the same.

The clearances came from a trade source - apparently Duke revised the clearances as manufacturing tolerances allowed. I used these 2 years ago with no probs and perhaps more importantly, no need to change any after 12k. miles. Only changed when I reseated the valves.

Ped

[norrie]

The Haynes manual says this.

Inlet opening clearance 0.10 to 0.12 mm.
Exhaust opening clearance 0.12 to 0.15 mm.

Inlet closing clearance 0.03 to 0.05 mm.
Exhaust closing clearance 0.03 to 0.05 mm.

I will be looking at doing mine again this year.
I think to be honest as long as you a getting some clearance you should be ok.
If the clearance is slightly to big it will rattle a bit but if the clearance is to small or there is no clearance at all that's when you run into problems.

Or that's what I think anyway.:scratch:


Norrie.

[Fosse Foxfight]

I will be looking at doing mine again this year.
I think to be honest as long as you a getting some clearance you should be ok.
If the clearance is slightly to big it will rattle a bit but if the clearance is to small or there is no clearance at all that's when you run into problems.

Or that's what I think anyway.:scratch:


Norrie.
The clearance in the Haynes manual are OK, but the ones that Ped has specified are better.
But again the glibness in your post Norrie is amazing. Ducati desmodronics are not Tonka toys...they are not hammers or chisels. They are a quite incredibly accurately constructed mechanism, entirely unique to this engine and need exacting maintenance and care. "Slightly too big"?....whats that 0.02mm, 0.2mm, 0.5mm?....."too small"?....0.002....0.001....0.0008? This is why if you are in any doubt whatsoever as to maintenance of your desmos you shouldnt even think about it and leave it to an expert....and I do mean an expert.
Sorry Norrie, no offence meant, but then as a chap I know you wont take it as such.

ta ra

[crust]

Ducati desmodronics are not Tonka toys...they are not hammers or chisels. They are a quite incredibly accurately constructed mechanism, entirely unique to this engine

Nah, its old school technology as used on old bikes ridden by men smelling of wee (;) ) or even worse cars built by budding Nazis


http://speedwaybikes.fortunecity.net/desmo.htm

or

http://www.teamyikes.com/desmo.html

:)Crust

[Fosse Foxfight]

It appears that sometimes I get a tad too passionate about mechanices and the like and have even been known to call people foolish for not maintaing their machines correctly:D Well, all I can say is if you aint prepared to look after your bike the way its meant to then you dont deserve it and whoever dont like that can lump it.

For those of you who love their bikes this small treatise by those superb chaps at Sigma Performance describes very nicely that little unimportant system that hides behind those sidecovers and under the little inspection covers on your cylinder heads...yes D*sm*dr*ni*cs...ssssh. Its very nicely written and indeed its written as a supplement to a Ducati circular that some of you owners of recent machines might find of interest.

http://www.sigmaperformance.com/rockers.html

[Fosse Foxfight]

Nah, its old school technology as used on old bikes ridden by men smelling of wee (;) ) or even worse cars built by budding Nazis


http://speedwaybikes.fortunecity.net/desmo.htm

or

http://www.teamyikes.com/desmo.html

:)Crust
Hehe, trust Crust to dig out the JAP reference, the key word in that piece Crust is Coventry.........they should have stuck to side valves. I never knew the about the Mercedes work tho. But as you can see from the time line the only manufacturer to bring it into production and continue with its use and indeed do it so well that its twin cylinder machines pissed over theoretically higher powered Jap fours was........yeah....you're ridin em.

ta ra

[Pugi]

Removing the tank will obviously give more access, but is it necessary? I too have no way of turning of fuel flow and would prefer to leave the tank upright.

[Pedro]

Removing the tank will obviously give more access, but is it necessary? I too have no way of turning of fuel flow and would prefer to leave the tank upright.

You'll struggle with the tank in place. I use small mole grips wrapped in tape to clamp the fuel hose while I remove it then plug the hose with a socket extension bar. With the tank on, you'll struggle to see properly and risk the hinge point getting stressed.

Ped

[Pugi]

With the tank on, you'll struggle to see properly and risk the hinge point getting stressed.
Ped

Have thought of this earlier and come to the conclusion that it might be why so many tanks develope a leak just there.

[JayT]

I'm fancyin doing my 12,000 mile service myself. How does this effect re-sale value, and can you advertise the bike as having had a 12,000 mile service even though it has not been performed by Ducati.

Afterall I dont fancy splashin £350 for some1 to change two timing belts and tell me the clearances were fine.

Thanks!

P.S in case my bike is reading this......"Dont worry love, i'm not wanting to sell you, I was just wondering!":gromit:

[Pedro]

I'm fancyin doing my 12,000 mile service myself. How does this effect re-sale value, and can you advertise the bike as having had a 12,000 mile service even though it has not been performed by Ducati.

Afterall I dont fancy splashin £350 for some1 to change two timing belts and tell me the clearances were fine.

Thanks!

P.S in case my bike is reading this......"Dont worry love, i'm not wanting to sell you, I was just wondering!":gromit:

To be honest, it probably will affect resale as most prospective owners are looking for full Duke history and will bargain if it's not complete. There are other things covered in the 12k service apart from belts and shims

Ped

[norrie]

The clearance in the Haynes manual are OK, but the ones that Ped has specified are better.
But again the glibness in your post Norrie is amazing. Ducati desmodronics are not Tonka toys...they are not hammers or chisels. They are a quite incredibly accurately constructed mechanism, entirely unique to this engine and need exacting maintenance and care. "Slightly too big"?....whats that 0.02mm, 0.2mm, 0.5mm?....."too small"?....0.002....0.001....0.0008? This is why if you are in any doubt whatsoever as to maintenance of your desmos you shouldnt even think about it and leave it to an expert....and I do mean an expert.
Sorry Norrie, no offence meant, but then as a chap I know you wont take it as such.

It perhaps came across as though I haven't a f#####g clue and perhaps I shouldn't post things like this on a Forum where anyone can read it and not just mechanics.
I'm sure you know what I meant though is yes the clearance is important but most tight clearances like this will be measured different by each person that does it and what I was trying to say is make double sure you have got a clearance there or you can run into problems.


Norrie.