Valve clearances .

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Bevel bob
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Valve clearances .

Postby Bevel bob » Tue Jun 15, 2010 2:07 pm

Out of interest I checked through my books and notes and came up with ten different reccomendations!!, Running clearances for M1 cam vary from 2 thou!! to 16 thou.Back in the 1960's I used Vic Camps figures of 3 and 5 thou and managed to do 104 mph,so they work. however the inlet clearance tends to close up and needs too much checking at these figures.Taking an average of the ten different recommendations gives me 5thou in and 8 thou ex. Close to the 6and 8 i'm using!! what say you?. I think the clearances need to be set to give the correct valve timing and the actual clearance is not relevent??
Last edited by Bevel bob on Wed Jun 16, 2010 8:33 am, edited 1 time in total.

Eldert
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Re: Valve clearances .

Postby Eldert » Tue Jun 15, 2010 4:14 pm

Hi Bob

intake 5/6 thou and exhaust 7/8 thou that about what most camshaftgrinders recommend .
so your OK with your settings

Eldert

Bevel bob
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Location: Bromley Kent UK.

Re: Valve clearances .

Postby Bevel bob » Tue Jun 15, 2010 5:33 pm

Thanks Eldert.

DewCatTea-Bob
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Re: Valve clearances .

Postby DewCatTea-Bob » Wed Jun 16, 2010 12:48 am

" Back in the 1960's I used Vic Camps figures of 3 and 5 thou and managed to do !04 mph,so they work. "

____ Exact valve-clearances (within reason) will have no effect on top-speed, etc.!
I've already posted that the FACTORY-recommended clearance-specs for the M-1 ARE 6-thousandths -(.15mm) for the intake, and 12-thousandths -(.3mm) for the exhaust !!
__ I wouldn't recommend second-guessing the factory on this, as they should know best what figures are needed to cope with not only the clearance-ramps on the cam-lobe, but also how much expansion the two separate valves could possibly eat-up of their preset-clearances.
Setting the intake valve too tight could hurt the engine's good-running, and a too tight exhaust may also burn the valve & seat as well !
(And of course a little too lose, is noisy.)
__ So I see no good reason to play-around with the valve-clearances ! ...
I would NOT post any such figures that are in-question (without stating that they might not be correct!) !
Any such specs which I post are the Ducati-factory's very-own, therefore there's no real need to search elsewhere for same !


" I think the clearances need to be set to give the correct valve timing and the actual clearance is not relevent?? "

____ I'm sure that ya really know-better than that !


DUCATIly,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

Bevel bob
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Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Valve clearances .

Postby Bevel bob » Wed Jun 16, 2010 7:48 am

Thanks DCT bob, Most interesting!, I've never seen a factory book so i'll accept what you say and value your opinion.My information initially came from a Clymer book 10 and 16 thou, and i soon found plenty of errors in it.I then asked around and found that those who build and race (over many years) recommend smaller clearances ,I have also proved to myself that with my usage I dont suffer burnt valves, Its possible that the factory anticpated that the bike would be used hard enough to need these clearances however that does not apply.I would prefer less noise and impact loads on the cam.I will obtain another set of lash caps to try out the larger settings,its also possible that the factory cam timing will prove easier to achieve with the larger settings. We will see!!. I have never believed that the "Factory always knows best" and take a view, They did make some daft camshaft choises don't you know!----------- Just found a webb page of a factory handbook---2 and 4 thou !! running and setting!!.All good fun. :D :D

DewCatTea-Bob
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Re: Valve clearances .

Postby DewCatTea-Bob » Wed Jun 16, 2010 6:30 pm

" My information initially came from a Clymer book 10 and 16 thou, "

____ As I recently indicated in another post/thread, THOSE two settings are the required clearance-settings for when taking readings of the valve-timing ! _ And they're 4-thousandths-of-an-inch greater than the 'running-clearance', so as to correctly avoid the clearance-ramps of the cam-lobes, (which would otherwise cause incorrect-readings!).
__ Some of the Clymer manuals happened to make this 'running valve-clearance' error simply due to mistakenly mislabeling the figures which had been meant only for checking the valve-timing ! _ (I do think that's inexcusable since their older editions had it all right in the first-place !)


" I will obtain another set of lash caps to try out the larger settings,

____ I also had stated before that your stated clearances (of .005 & .008) were close enough and that only your exhaust-setting might be slightly too tight... So you really don't need to worry about resetting them any larger very soon, and could just as well hold-off until you've put a couple hundred miles on the motor, to then check & reset them.
__ My strong-advice is to not set them any tighter than 33% under the factory-specs (which would be 4 & 8 thou., in this case).
Cuz if tighter clearances then cause the cam-lobe clearance-ramps to crack-open the valves any sooner than intended, then performance & related parts-longevity will be reduced.


" I have never believed that the "Factory always knows best" and take a view, "

____ Certainly I agree that the factory doesn't always know best, BUT, I'd prefer to thrust THEM over anyone else who's not at least an equally established engineer in the field ! - (For another example,, we all realize that Microsoft does things which are not the best-way, but, it's much likely better to trust them/(M$), rather than most any PC-owner who thinks he knows better than M$ !)


" They did make some daft camshaft choises don't you know! "

____ I actually believe that the heads of the Ducati-factory had pretty-much always really knew all the right-things to do concerning their various camshafts ! _ Thus I squarely blame outside sources (such as the Italian-gov & Berliner) for those few poor choices which were made.


" Just found a webb page of a factory handbook---2 and 4 thou !! running and setting!! "

____ I'm quite positive that's bogus, for the Mach-1,, but may be correct for another cam (such as the G&W).


DUCATIly,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

Bevel bob
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Location: Bromley Kent UK.

Re: Valve clearances .

Postby Bevel bob » Fri Jun 18, 2010 1:05 am

Thanks Bob,I think before i make any changes i need to determine exactly which cam i have,so a valve timing check is needed although the lift seems to indicate grey/white .
My only current problem is a hesitation comming off the overun which no amount of carb fiddling seems to affect(unworn slide ssi29d).

DewCatTea-Bob
Posts: 2897
Joined: Sun Nov 01, 2009 10:53 am
Location: Near SE side of Lake Michigan

Re: Valve clearances .

Postby DewCatTea-Bob » Fri Jun 18, 2010 11:39 am

" I think before i make any changes i need to determine exactly which cam i have,so a valve timing check is needed although the lift seems to indicate grey/white "

____ Your discovered lift-figure readings would have to be fairly far-off, (and also coincidentally so!), in order for your camshaft to not be the 'Grey' (not "grey/white") Mach1-cam ! _ (The 'Grey&White' color-code is for the 450 DESMO-cam!)


" My only current problem is a hesitation comming off the overun which no amount of carb fiddling seems to affect(unworn slide ssi29d). "

____ The SSI-carbs have always been a fuss of sorts ! ...
__ Have you messed-around with the so-called 'choke' set-up on yours?
What number is it's throttle-slide, 80 or 100 or what,, and what needle-position have you chosen?
Do you have it's float-bowl set vertically when your DUKE is standing-upright?


DUCATIly,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob

Bevel bob
Posts: 1043
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Valve clearances .

Postby Bevel bob » Sat Jun 19, 2010 5:49 pm

I have standard settup appart from a 107 main jet (a bit small perhaps) and no choke at all . the top has a brass blanking plug (it was a racer).The slide is a 60 needle std position, emusion tube as recomended by Road and Race, 260 which is normally a 265? carb and float vertical in line with engine, fuel level checked as per Dellorto spec. Some seem to find an 80 slide works so may try one.Needle position as book.

DewCatTea-Bob
Posts: 2897
Joined: Sun Nov 01, 2009 10:53 am
Location: Near SE side of Lake Michigan

Re: Valve clearances .

Postby DewCatTea-Bob » Sat Jun 19, 2010 7:59 pm

" The slide is a 60 "

____ I'd first try a #100 throttle-slide, (or a #50), to find-out if your issue (which I'm not exactly sure of), gets better or worse, thus learn if such change even matters in your case.
I've found that most often it's the slide, if not the air-screw adjustment, that causes/solves such issues !


Hopeful-Cheers,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob


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