Vento 350

[DewCatTea-Bob]

By: Eldert...
" there is something odd about the timing figures .
on my degree wheel it goes from zero to 90 degrees and then back to zero again "

____ Eldert, could you please elaborate on exactly whatever in particular you're actually meaning to refer to ? ...
As you've left your post-wording, I'm led to assume that you're possibly referring to the inconsistent v.timing-figures stated for the Lento-version, as the figures stated within the Lento-version's crankshaft/cam-timing depiction don't all exactly match-up with those listed, (as seen listed below the corresponding depiction). ...
While the crank/cam-timing depiction for the Rapido-version and IT's corresponding listing below, actually both do have PROPERLY matched-up figures,, it seems somewhat obvious that the depiction for the Lento-version was borrowed-over from the Rapido's, and was quite very poorly adapted to also properly reflect the actual figure-representations for the Lento-version, (and thus the Lento-version's depiction-figures don't all properly correspond with the associated listed-figures). _ Therefore I don't trust all the figures stated within the Lento-version's depiction, however I do believe that the stated-figures in the listing (below the Lento's depiction) are correct.
__ Despite that outwardly blatant published-error, I'm thinking that Eldert's concerned-issue is probably about something-else still.
So hopefully he will get whatever his particular presented-issue cleared-up sometime soon.


Hopeful-Cheers,
-Bob

[Ventodue]

Just in case a bit of translation helps :

RAPIDO (orange and white)
Inlet
Opens at 72° before TDC
Closes at 100° after BDC

Exhaust
Opens at 98° before BDC
Closes at 80° after TDC

LENTO (grey)
Inlet
Opens at 68° before TDC
Closes at 95° after BDC

Exhaust
Opens at 84° before BDC
Closes at 78° after TDC

(PMS = Punto muerto superior = Top Dead Centre. PMI = Punto muerto inferior = Bottom Dead Centre)

These specs come from the owner's handbook. And are confirmed in "Ducati (Mototrans) much más que una licencia de fabricación" by Francisco Herreros. However, I don't know what the measurement clearance is. But I believe it's normally 1mm for Ducatis - ?

Btw, Muzz: Jon Peglar is very knowledgeable on the Mototrans bikes - much more than me! He's on this Forum from time to time.

Feliz navidad!

Craig

[Ventodue]

... as the figures stated within the Lento-version's crankshaft/cam-timing depiction don't all exactly match-up with those listed ..

Ha! Hadn't noticed that! You've got sharp eyes there, Bob ... Good pick up!

[Ventodue]

Hi Bob,

Would I be right in thinking that, given the fact that for 7 out of the 8 cam angles there is no more than 5°difference, the best way to tell the which cam is which would be to measure the opening of the exhaust valve? Because there there is a (notional) difference of 14° - ?

Un saludo

Craig

[DewCatTea-Bob]

" These specs come from the owner's handbook. "

____ Thanks for independently listing those stated v.timing-figures Craig, as I was thinking of doing the same myself (since those you had copy-posted were not very clearly copy-printed).
If I had gotten to that task before you did, I was also going to list the equivalent figures for the two Green & White camshafts, as well, (for comparison).


" I don't know what the measurement clearance is. But I believe it's normally 1mm for Ducatis - ? "

____ NO... I believe the 1mm-standard lift starting-point is a Japanese-set standard, (which is not a FAIR method for determining a camshaft's ACTUAL valve-timing !).
Where-as Ducati's method of measuring their cam's v.timng is done the fair way. ...
Ducati FAIRLY takes-out MERELY the individual camshaft's particular 'clearance-ramp' (which precedes the lift-ramp), away-from the measurement-reading, so as to then measure JUST the cam-lobe's actual INTENDED-lift only.
And-so since many of Ducati's camshaft-models have differing clearance-ramps, each individual camshaft-model is thus-then supposed to have it's v.timing measured with the valve-clearance reset to some individually given factory-setting, so as to then fairly measure the v.timing of a particular cam-model (without also unfairly getting the clearance-ramp mixed-up into the measurement-reading).
The Jap.method gets-around the complication of varied clearance-ramps, by just simply allowing an even 1mm to absorb whatever the clearance-ramp may be on any particular cam, (thus unfairly also absorbing some unknown portion of the actual lift-ramp of a cam-lobe as well).
__ I don't know what the valve-clearance is supposed to be reset to (so as to avoid including the clearance-ramp into the measurement-reading of the actual lift-ramp), for the cam-versions of the Vento camshaft-models. _ However I'd most suspect that the factory-recommended clearance-settings would be close to, (if not the very same as) that recommended for the G&W.camshafts.
____ Also, I note that you've stated that the color-code of the camshaft for the Rapido-version is "orange and white", and the Lento-version's is "grey" ...
I can't confirm whether the orange&white code is correct or not (for the Rapido-cam), but, the Lento-version's cam.color-code can't be "grey" because, 'gray' is the color-code for the Mach-I camshaft (which is too widely different to share a color-code with).
__ Where did you learn-of those supposed color-codes from ?
Could it be that rather than "grey", the Lento-cam's color-code may be 'gray & white' ? _ Or even perhaps ALSO orange&white, since the two Vento cam.versions are so similar,, cuz Ducati has already before used an identical color-code for two other camshafts that were similarly varied - (that being the green&white color-code designated for both the 250F1 & the 350M3 camshaft-models).
__ For comparison, here are the v.timing-figures for the two G&W.cams...
INtake - opens BTDC / closes ABDC _ EXhaust - opens BBDC / closes ATDC
'250-F1' cam = 70BT / 84AB _____________________ 80BB / 64AT
'350M3' cam = 65BT / 76AB _____________________ 80BB / 50AT


DUCATIly,
-Bob

[Ventodue]

NO... I believe the 1mm-standard lift starting-point is a Japanese-set standard ...

Ah, interesting ("Me, I know nuttin'".. ). I got the 1mm reference from here, btw.

http://www.ducati-upnorth.com/tech/camtiming.php

[DewCatTea-Bob]

Would I be right in thinking that, given the fact that for 7 out of the 8 cam angles there is no more than 5°difference, the best way to tell the which cam is which would be to measure the opening of the exhaust valve? Because there there is a (notional) difference of 14° - ?

____ Right, good reasoning ! _ And since Ducati allows a +/- 5-degree tolerance in their actual camshaft v.timing-figures, your point becomes quite significant to discern the Rapido & Lento cam.versions apart from one another, as there may thus-then possibly be only-just 4-degrees difference between the two differing cam.versions at that ex.valve opening-point.



" I got the 1mm reference from here, "

____ I suppose that by THESE-days, (sometime since Ducati abandoned their tower bevel-gears, for belts), Ducati ALSO may have converted-over to that (possibly now world-standard), 1mm-standard lift-point (began by the Japanese).
Which if so, would be a shame since that imprecise method compromises fair comparison of differing v.timing-specs (between various camshafts' ACTUAL valve-timing).


Dukaddy-DUKEs,
-Bob

[Ventodue]

Ta Bob - good stuff.

As to ...

Also, I note that you've stated that the color-code of the camshaft for the Rapido-version is "orange and white", and the Lento-version's is "grey" ...
<snip>. Where did you learn-of those supposed color-codes from ?

They're the codes given in the owner's manual and also in the Herreros book (which may just be copying an error in the manual, of course ). But I'd hazard a bet that, even tho' the Mach 1 had used a gray-coded cam, Mototrans felt themselves sufficiently distanced in time and space to use the same color ...

P.s Just done a bit more looking. Here are the specs from the parts book (bottom left):


This is the same spec that the owner's manual gives for the Rapido cam. And down below I see it reads:

"Regulación de control entre válvula y balancín 0,1mm"

Pps. Thought you might like to see this too, Bob - same source, i.e the parts manual.



Un saludo

Craig

[DewCatTea-Bob]

____ Thanks for another informative post, Craig !


" They're the codes given in the owner's manual and also in the Herreros book . But I'd hazard a bet that, even tho' the Mach 1 had used a gray-coded cam, Mototrans felt themselves sufficiently distanced in time and space to use the same color ... "

____ That's really too bad, darn-it ! ...
Cuz Ducati has already used the gray-code for two other camshaft-models ! - The Mach-I & the WideCase Mark-3 Duke-models.
__ For comparison, here follows the two Gray-coded cam-v.timing figures...
___ INtake - opens BTDC / closes ABDC ___ EXhaust - opens BBDC / closes ATDC
The 'Mach-I' cam = 62BT / 76AB _______________________ 70BB / 48AT
'250M3' w-c.cam = 60BT / 70AB _______________________ 70BB / 50AT
(Side-NOTE: The pre-1965/n-c.Mark-III camshaft's color-code is 'Red', while the post-1964/n-c.Mark-3 employed the Gray/M1.cam .
Also, I have already added the figures for the two Green&White cam.models, two self-posts prior/back.)
____ IF the normal running-v.clearance is supposed to be near .002", THEN the resetting of the valve-clearance to ".1mm", (as you seem to have found & posted), for the particular-purpose of measuring the camshaft's v.timing, seems to be a reasonable amount of set-clearance for bypassing the expected clearance-ramp and-yet still catch pretty-much all of the cam-lobe's entire intended 'lift' .
However I really don't read Spanish too well, and-so I could just as well expect that that stated ".1mm" may actually be the intended 'running-clearance' for the normal operation of the valves, (in which case, .2mm may then be more like the needed clearance required to check the actual cam.valve-timing).


Dukaddy-DUKEs,
DCT-Bob

[Jordan]

Is it possible to work out how much cam timing clearance should be used, if you didn't know?
For example, could an abrupt change in contour signify the "real" opening point?

Jordan