450 Mark 3 engine rebuild and cam change

[graeme]

Excuse me Kev,
Hello Bob,
I'm having trouble posting pictures as I don't have a computer connected to a fast internet yet (building a house and living in a shed) so bare with me and I'll post pictures asap.
Fitting PHF's to 450 singles still is very tight regardless of which manifold is used.
The RT is the easiest but using a straight Malossi manifold and rubber coupling still requires some fiddling.
The manifold used on the scrambler has been home made by someone in the past.
The Desmo with the 36mm has a 250 frame, but still requires the fuel tank to be lifted a little to clear the top of the carb.
Graeme

[machten]

Had some opportunity to do some further testing over the last few days. I'd expected Marco's 450 Desmo config with the Conti style pipe of 135 main/50 pilot/ 70 choke/ 60 slide/ V13 needle and 265M atomiser-needle jet would be what I'd require for the 450 springer with a G&W cam. Interestingly, best performance for my 450 with the Conti style pipe and a long bell mouth best utilises a 58 pilot jet (everything else the same)- I suspect a 55 would be OK but I don't have one to hand. Anyway, it's idling well, progressing well and pulling well over 6K so far.

Kev

[DewCatTea-Bob]

____ The below quoted-postings dated Jan.16th ~ 17th have been continued-on here copied from another fairly unrelated thread.......

I'm in the process of working out a new starting routine since I installed a green and white camshaft.

Postby graeme » Fri Jan 16, 2015 11:33 pm

Hello Kev,
Does the green white cam make much difference to a 450?
Is that the only change from standard?

Graeme

" Does the green white cam make much difference to a 450? "

____ It's quite certain that Kev-himself has not-yet acquired any where near the experience that I-myself have gained (from back in the '70s) ! _ So here's what I know considering your question...
__ Compared to a std.450-DESMO, a springer-450 with any G&W.camshaft-model installed, makes no notable difference in performance !
However when replacing the stock (mild) White-cam.model, the (wild) G&W.cam makes a hell of a difference !!
So a G&W.cam-equipped 450 exploits (at-least) pretty-much the same performance-characteristics as a std.450-DESMO.
__ So Graeme,, all you basically have-to do to answer your-own question, is compare your 450-Scrambler with your 450-R/T.


Duke-Cheers,
-Bob

[DewCatTea-Bob]

Postby Bevel bob » Sat Jan 17, 2015 12:03 am

I have learnt that there are more than 1 type of Green/white with very different timings so you need to be more specific. Also the effect of these timings are quite different depending on the motors capacity.Look at previous posts.

" I have learnt that there are more than 1 type of Green/white with very different timings "

____ Actually the only noteworthy difference between the two, is the amount of 'overlap' valve-timing.
But that (fairly significant) difference makes no notable difference in the performance of a 450.



" Also the effect of these timings are quite different depending on the motors capacity. "

____ That's indeed pretty-much true, as larger cyl.capacities tend to make otherwise wild-cams seem milder-performing (concerning engine-power 'peakiness' ), as compared to when running within smaller-capacity engines (with the same port-size/plumbing-capacity to cyl.volume ratio) !


Dukaddy-DUKEs,
-Bob

[DewCatTea-Bob]

stby machten » Sat Jan 17, 2015 12:27 am

Hi Graeme,

The short answer is, I can't be absolutely sure what improvement it contributes on its own based purely on my own experience. I was rushing against the clock to get the 450 together for the Albany Hill Climb including an engine strip and rebuild as I needed to get the little end re-sleeved and I knowingly committed the cardinal sin of a doing a few things at the same time.

The two things I did at the same time that make it hard to be sure were changing the camshaft and installing a Conti style exhaust pipe. The combination of the two definitely contributes more power from mid range upwards. Previously, the white camshaft and stock silentium exhaust ran out of puff (and topped out the revs) much earlier. I'd estimate the new set up provides access to nearly another 1000 RPM. Interestingly, I think I've lost next to nothing down low. I also needed to play around with the VHB jetting just a little bit to better suit the new arrangement.

One thing I have tried as an experiment was to put the Silentium back on with the G&W camshaft. Forget it. It won't run over 4000 RPM. You have to run with the megaphone style pipe. I wouldn't be at all surprised if the exhaust pipe change contributed as much or even more to the performance improvement as the camshaft change did.

I'm curious myself, so when I have some time (ie. when I've sorted out a few "must do" things on my other mechanical mistresses from Bolonga) I'm going to put the White camshaft back in and test exactly what you are asking.

I've never figured out why Ducati went to the trouble of producing and installing a G&W camshaft for the 350, but used the 250 Scrambler White camshaft in a 450. It defies logic to me. I know when Lex and I were in Europe during our occasional "jousts", he on his '69 350 with a Silentium cigar type exhaust and me on the 450 with the stock Silentium pipe, I'd easily get to about 55mph in front of him, but after that, he was going past me.

Here's the 450 in Hill Climb config with the Conti style pipe from Road & Race...

Image

I don't know exactly what RPM I was getting up to on the climbs as we have to have our speedo and tacho covered (it's a time trial, not a race...yeah, right!), but it sure is much more free up top.

Image

Kev

" I think I've lost next to nothing down low. "

____ I must assume you've made that conclusion only based upon how strong your 450 takes-off in 1st.gear with regular lowish-RPM launches.
And indeed it's not easy to discern any actual difference that-way, as 1st.gear-acceleration at low speeds doesn't really exhibit engine-power differences much enough to tell for-sure !
So to really witness the actual difference in power-output,, ya have-to have two otherwise identically-matched 450s (except for their cam.models), and a couple of equally sized riders,
and run the two side-by-side near-around 30-MPH in 4th.gear (for comparing low-RPM.performance), and simultaneously fully-open both throttles. _ Then you'll be able to rather-fairly experience the difference, (which will then show the White-cam equipped 450 strongly trot away from the other 450 with the G&W.cam), thus-then become fully aware of how much low-end power has really been lost (with the G&W.cam in place of the White-cam) !



" One thing I have tried as an experiment was to put the Silentium back on with the G&W camshaft. Forget it. It won't run over 4000 RPM. "

____ I'm left to assume that the particular "Silentium" which you're meaning to refer-to is actually the shorter/stock Scrambler-style version, correct ?
If so, then there's something-else wrong if you actually literally meant that "it won't run over 4000 RPM",, so I rather assume that your must really mean that decent acceleration falls-off after that RPM.range, thus making that muffler/cam.model-combo to be pretty-much worthless.
__ I-myself have never tried-out that 'shorty-Silentium' & G&W.cam combo,, but another 450-Jupiter owner I knew, had me install a 250F1-G&W.cam (taken from a late-69 350Scr), and he later reported-back how very-disappointed he was with the resulting power-output not-only being pretty-weak above 5000-RPM, but also that he suspected his 450's power had more-or-less diminished over the entire rev.range.
I told him that I hadn't expected him to keep continuing-on running with his original rusting-up (but not-yet rusting-out) stock-Scr.muffler, and to try knocking-out it's baffle. _ And doing-so then provided a marked improvement from mid-range upward, (and considerably better even more-so than with the long Mark3D-style stock Silentium missile/tube-muffler) !



" You have to run with the megaphone style pipe. "

____ With most-any wild-cam, any connected exhaust-system must have rather free-flowing ex.air-flow in order to make good/worthy use of the wild-cam's intended ability ! _ So a megaphone-shaped muffler really isn't absolutely required.



" I wouldn't be at all surprised if the exhaust pipe change contributed as much or even more to the performance improvement as the camshaft change did. "

____ Ducati made a shorty-megaphone for the 450,, and it really helped power-output most-everywhere across it's entire rev.range, especially with the G&W and DESMO cam.models !
__ While that-change alone certainly always makes a notable improvement in power-output, and a wilder-cam doesn't likewise also always do-so,, it's really not exactly fair to assume that free-flowing mufflers will provide even-more of a power-boost than wilder-cams are well-known for, mainly because wilder-cams more-so depend on airflow-momentum and-so a wild-cam working-together with a restrictive muffler will rather-instead KILL overall-power ! _ And-thus then, the installation of a non-restrictive ex.system certainly will indeed provide the greater power-boost. _ But if ya rather fairly start-out with a lightly-restrictive muffler,, then the installation of a wilder-cam can likely make the greater power-contribution, more-so than can be gained by replacing the muffler with a totally free-flowing/straight-through ex.system.
To conclude this paragraph with a 'bottom-line',,
the exhaust-system & cam-timing are pretty-much interdependent for max.power-output, so neither-one alone can always be depended-upon as being the strongest contributor to increased power !



" I've never figured out why Ducati went to the trouble of producing and installing a G&W camshaft for the 350, but used the 250 Scrambler White camshaft in a 450. It defies logic to me. "

____ I've gone-over this issue of concern at-least once before - (viewtopic.php?f=3&t=195&p=1667#p1667 ), and it certainly indeed defies good/reasonable logic !
__ Ducati-itself -(actually their engine-design dept) was pretty-much like-minded to myself in-that every engine-model ought-to have it's very-own camshaft, however the responsible penny-pincher overseers would somewhat curtail that fairly sensible reasoning on occasion, and cause economically-based consolidation, (the 1966 250GT/Monza being a prime-example of such efforts). _ So that endeavor could possibly be the original blame for why the 350-Scr.engine was ever fitted with the very-same camshaft-model that was originally designed specifically for the 350Mark-3. _ However at some point before that, there must've been a more suited cam.model that was intended for specific use for the 350-engine of the 'Scrambler' model-line, because I recall reading in an English-publication that the 350-Scrambler employed a "White" color-coded camshaft ! _ And besides that, I once seen a reprint-copy of a 1967 supplemental-type Italian parts-book that listed the unique parts of the new 250-350Scr.models, which included their very-own (never before existing) camshafts, (of which I had then noted their part-numbers). _ So there must've been some countries or others which rather received 350Scr.models with an actual Scr.type White-cam.model (as logically preferred by Ducati).
Anyhow,, the most-likely reason for why the newer 350Scr.models later became fitted rather with the even wilder (preexisting) 250F1-camshaft, is less cloaked in mystery... 'Berliner'.
Sometime by late 1968 Berliner had come to prefer that the more appealing*appearance (* for within the USA at-least), of the w-c.Scrambler-model, should-ought thusly rather be the Duke-model that offers 'cycle-riders' the whole-package,, and-so Berliner themselves came-up with a unique model-designation for their-own conceived Duke-model, by specifying that Ducati install their 'hottest' camshaft (which was then the 250F1-cam) into the pre-existing 350-Scrambler, so that Berliner could then announce the 'new' "350SSS" model (which I think stood for Street/Scramble/Sport). - (Try searching ' 350SSS ' , if further interested.) _ So it was the Berliner marketing-dept who rather conceived the (stupid !) notion of employing a racing-cam in a scrambler-type model, (as their conception was that the resulted 350-model was no-longer really a pure scrambler).
Now while it's of-course quite certain that Ducati well realized that a racing-cam combined along-with a street-legal muffler is a power-canceling combo (rather than any 'souping-up' of the bike/engine),,
the present-day mind-set of nearly the entire general (male) motorcycling-public back-then, was that 'HOT cams' make your cycle go FAST!, (with no 'ifs-ands-or-buts'). _ So understandably likewise, those in charge at Berliner also believed the same as most-all (non engineer-type) diehard-motorcyclists, and expected their '350SSS' to be an appealingly good-looking & fast motorcycle to desire owning. _ (As after-all,, the well established typical-example concerning the hot/wild M1.cam transplanted into the resultinghly SUCCESSFUL 250-Mk3, had essentially validated the general consensus that hotter-cams make motorcycles run faster !)
Trouble actually is though,, that the overly wild cam in a street-legal motor/cycle, actually made the w-c.350s slower (instead of faster, as had been expected) !
And the reason-why some other countries also received 350Scr.models with the same non-Scr.cams, must be due-to the economic-factor, (since the U.S. was the #1 market for the 350Scr.type Duke-model).
__ So the above text/wording addresses the issue of overly wild cam.models being found within w-c.350-models that rather appear as mere 'Scrambler' models.
Next (below), I'll address the concern of a (so-assumed) 250-cam.model found in 450s issue.


" I've never figured out why Ducati went to the trouble of
installing a G&W camshaft for the 350, but used the 250 Scrambler White camshaft in a 450. "

____ I know Ducati employed three different camshaft-models within std.450-models,,
the 450Mk3 & 450Scr cam.model-versions and-also the same White-cam that came stock in 1968-70 250Scr.models, (although I have fair reason to suspect that that-cam was originally designed for the 350Scr.model, [since an established w-c.250Scr.cam-model already existed for the 1967 w-c.250-engine !]).
__ I was never able to get my hands on either version of the true 450-cam.models, as all non-DESMO camshafts I-myself have ever removed & measured from all (non-DESMO) 450-models, unfortunately proved to be the same White-cam.model as found stock in all post-1967 w-c.250-Scr.models.
That most-all non-DESMO 450-models (including the 450Mk3 !) produced for importation into (at-least) the USA came stock with the same non-450 White/Scrambler-cam.model, was no-doubt certainly due-to economical concerns !
(It's sorta as-if Ducati had produced all the w-c.1967 350-Scr.cams they'd ever need for their 350-Scr.model-line,, but-then after Berliner demanded G&W.cams instead, they then had-to find homes for all the orphaned 350-Scr.camshafts.)
It's too bad that Ducati had-to employ the cam.model they did in any of their 450s, cuz even the real (somewhat wilder) 450Scr.cam is a little on the mild-side for any 450-single !


Dukaddy-DUKEs,
DCT-Bob

[DewCatTea-Bob]

Postby graeme » Sat Jan 17, 2015 1:58 am

Ta Kev,
That explains a lot for now.
Thanks for the pictures.
I have a yellow 74, an RT and a dunga 450 '74 scrambler. (dunga as in not restored and very ugly but it goes)
The difference between the three bikes is an extra step in power for each engine. (the yellow engine has been made to breath and is by far the best)
I have a Grey (Gray) cam that I'll try in the scrambler and I can swap the pipe (conti type) from the yellow bike.
So just wondering what your feeling was with your 450.

Regards
Graeme

" I have a yellow 74, an RT and a dunga 450 '74 scrambler.
The difference between the three bikes is an extra step in power for each engine. (the yellow engine has been made to breath and is by far the best) "

____ What camshaft does your "yellow 74" 450 have within it ?



" I have a Grey (Gray) cam that I'll try in the scrambler "

____ How are you able to be sure that it's indeed the Gray-coded/Mach-I camshaft-model ?
__ If indeed it really is the M1/Gray-cam,, then I'm fairly sure that you'll be very pleased with the resulting power-improvement and power-output characteristics which that highly-desirable cam.model will instill within your 450-Scrambler, (pretty-much regardless of whichever muffler is currently employed) !


Duke-Cheers,
-Bob

[DewCatTea-Bob]

Postby machten » Sat Jan 17, 2015 6:29 am

I'd be interested to hear your thoughts on the effect of just trying the megaphone and maybe richening up the fuel a bit on the scrambler, Graeme. I find the 450's fairly lazy rev'ers anyway (in comparison to my 250, anyway).

The other thing to bear in mind I guess (regarding my lack of understanding re the White in a 250 and 450 and a Green & White in the 350) is that the Desmo singles used the same Blue & White camshaft through the range 230 - 450 as far as I know.

As Bevel Bob points out, there are at least 2 different Green & White camshafts that I'm aware of. The one I have in my 450 is a reproduction of one of them. I have the specs somewhere.

Lex's 350 experienced a reasonably distinct lack of power down low and riding along side it, even I could hear it start to come on at certain revs. Not the same distinctness, but a little like a slow two stroke power band. Even more noticeable at high altitude. I don't experience that on the 450, so it may be a different spec, or....

Other's in this place will be able to offer far better insights than me, I'm sure! In any case, please let us all know the results if you do the pipe change.

Kev

" I'd be interested to hear your thoughts on the effect of just trying the megaphone on the scrambler, "

____ A stock 450-Scrambler/Jupiter, responds fairly-well/considerably-better with most-any straight-through muffler (such as a glass-pack shorty), compared to the stock/Scrambler 'bullet-style' Silentium-muffler, (and-also even the w-c.Mk-3.type 'torpedo/cigar-style' Silentium-muffler), either with or without the internal baffle. _ But the optional shorty-megaphone can't be beat, and it makes the most improvement of all !



" The other thing to bear in mind I guess (regarding my lack of understanding re the White in a 250 and 450 and a Green & White in the 350) is that the Desmo singles used the same Blue & White camshaft through the range 230 - 450 as far as I know. "

____ That's indeed so (for all the std.production 250/350/450M3D & 450R/T models), and was done pretty-much just for economic reasons.
Otherwise the 350-DESMO would've gotten the Red&White-cam.model and the 450-DESMO would've gotten the Gray&White-cam.model.
The Blue&White DESMO-cam was selected for all three engine-capacities because it was the mildest and-thus the only one that could reliably work within all three engines.



" As Bevel Bob points out, there are at least 2 different Green & White camshafts that I'm aware of. "

____ I'm pretty-sure that there's only just the two Green&White camshaft-models... First the '250F1' factory-racer G&W.version (which the Blue&White-250D.cam was based upon), followed thereafter by the 350Mk3-version (which was merely a hotter version of the Mach-I/Gray-cam, [to be more suited for the near 100cc of extra capacity]).



" The one I have in my 450 is a reproduction of one of them. I have the specs somewhere. "

____ Unfortunately, many aftermarket camshaft offerings don't closely match their claimed-specs !
I much wonder what specs you got with yours !?



" Lex's 350 experienced a reasonably distinct lack of power down low
I don't experience that on the 450, so it may be a different spec, or.... "

____ As BevelBob had inspired to bring-up,, the end-effect of a cam's valve-timing directly varies according to cyl.capacity, and-so the smaller the engine, the greater a wild-cam kills the low-end power !


Dukaddy-DUKEs,
-Bob

[graeme]

Bob, to answer your two questions,
The cam in the yellow Desmo is the standard desmo cam.(I didn't know there was another factory cam other than the red white)
And, you identified the gray cam as such back about 12 or more months ago in a discussion about breathing. I think that was where I posted pictures of some cams.

Regards
Graeme

[DewCatTea-Bob]

Postby machten » Sat Jan 17, 2015 12:48 pm

My own words...

I'm in the process of working out a new starting routine since I installed a green and white camshaft. I suspect the much higher camshaft overlap requires a few more priming cycles to get sufficient fuel in the chamber for a good starting mixture. Previously, two induction cycles with the enricher on did the job, now it seems I need 4-6, but I'm still experimenting.

Does anyone have some thoughts about using a larger enricher jet for starting with the Green & White camshaft? I've got a few spare and could use a jet drill to enlarge one as a test. Just something I've been thinking about....

Kev

____ The same size enrichener-jet as used for a 450-DESMO should be sufficient.
However your mod.test seems to be of sound-reasoning,, and since you have a spare jet to experiment with, I'd suggest trying enlarging it's hole to obtain near-about a 20% increase in area (not diameter).


Hopeful-Cheers,
-Bob

[machten]

I've left things a few days before responding. Thanks for moving this from the other thread DCT-Bob. I apologise for my hijack. Graeme threw me the bait and I took it hook, line and sinker!

Anyway...to respond to a few things above...My apologies, there was a fair bit to respond to, so please forgive the length of this post

By DCT-Bob:

So a G&W.cam-equipped 450 exploits (at-least) pretty-much the same performance-characteristics as a std.450-DESMO.

I have in the last few weeks had the opportunity to compare sequentially (ie riding one immediately after the other - which I know is not a perfect method of comparison, but far better than none), my 450 Mark 3 equipped with the G&W replica cam I have and a 450 Desmo. Both 450's had identical "Conti style" exhausts fitted. My impression was that the springer performance was about equivalent to the Desmo. If anything, I thought my Mark 3 may have the edge, but it was too close to call. I should also mention that my Mark 3 is a fresh engine with only about 2000km on it. In any case, this experience provided to me nothing to contradict Bob's statement above, and some evidence to support it.

Kev: " I think I've lost next to nothing down low. "

DCT Bob____ I must assume you've made that conclusion only based upon how strong your 450 takes-off in 1st.gear with regular lowish-RPM launches.
And indeed it's not easy to discern any actual difference that-way, as 1st.gear-acceleration at low speeds doesn't really exhibit engine-power differences much enough to tell for-sure !
So to really witness the actual difference in power-output,, ya have-to have two otherwise identically-matched 450s (except for their cam.models), and a couple of equally sized riders,
and run the two side-by-side near-around 30-MPH in 4th.gear (for comparing low-RPM.performance), and simultaneously fully-open both throttles. _ Then you'll be able to rather-fairly experience the difference, (which will then show the White-cam equipped 450 strongly trot away from the other 450 with the G&W.cam), thus-then become fully aware of how much low-end power has really been lost (with the G&W.cam in place of the White-cam) !

Perhaps I should have said " I think I've lost next to nothing down low for normal street riding ". I was expecting to have a noticeably reduced low RPM tractability in normal riding (like I found with Lex's 350 springer with the G&W cam). I haven't found this to be the case. I think it is ever so slightly detectable, but the pull from 3000RPM seems to me to be quite similar. That surprised me a bit.

Kev: " One thing I have tried as an experiment was to put the Silentium back on with the G&W camshaft. Forget it. It won't run over 4000 RPM. "

DCT Bob: ____ I'm left to assume that the particular "Silentium" which you're meaning to refer-to is actually the shorter/stock Scrambler-style version, correct ?
If so, then there's something-else wrong if you actually literally meant that "it won't run over 4000 RPM",, so I rather assume that your must really mean that decent acceleration falls-off after that RPM.range, thus making that muffler/cam.model-combo to be pretty-much worthless.

No. I'm referring to the long one standard on the later Mark 3s (see picture below). I can't recall the IGM number off the top of my head. Before I put in the G&W camshaft, my original one had the rear baffle taken out, but it was starting to get a bit rattly and I had a new one around, so I installed it early last year. This still has all its baffles complete. It worked OK with the White camshaft although I'm sure it was restricting even that performance. With the G&W camshaft installed with the "new" Silentium, just over 4000RPM the bike will start missing (as in not firing). If I put the Conti style exhaust back on, no problem. I haven't tried the old Silentium with the final baffle removed.

Kev: " I wouldn't be at all surprised if the exhaust pipe change contributed as much or even more to the performance improvement as the camshaft change did. "

DCT Bob:____ Ducati made a shorty-megaphone for the 450,, and it really helped power-output most-everywhere across it's entire rev.range, especially with the G&W and DESMO cam.models !
__ While that-change certainly always makes a notable improvement in power-output, and a wild-cam doesn't likewise also always do-so,, it's really not too fair to conclude that an open-muffler provides more of a power-boost than a wild-cam can, because wild-cams more-so depend on airflow-momentum and-so an overly restrictive muffler working-together with a wild-cam will rather KILL power overall ! _ And-thus then, the installation of a non-restrictive ex.pipe certainly will indeed provide a greater power-boost,, but if ya rather fairly start-out with a mediumly-restrictive muffler, the installation of a wilder cam can make a greater power-contribution than a free-flowing/straight-through muffler can add.

That's probably a better way to put it, although I'm not concluding anything, merely saying I wouldn't be surprised if that was the case. In fact, as I posted in response to Graeme, I intend to test that out for myself sometime. I also wanted to indicate that before he goes to the effort and expense of a cam change, try changing the exhaust to a more free flowing system first.

Kev: " The one (G&W camshaft) I have in my 450 is a reproduction of one of them. I have the specs somewhere. "

DCT Bob____ Unfortunately, many aftermarket camshaft offerings don't closely match their claimed-specs !
I much wonder what specs you got with yours !?

I wrote down some dimensional measurements, but I haven't dialled it fro open/close degrees. It came from Road & Race. If ever I get through the "must do" stuff, I will do so.


Re my query on larger enricher jet to perhaps aid starting with the G&W camshaft:

DCT Bob: ____ The same size enrichener-jet as used for a 450-DESMO should be sufficient.
However your mod.test seems to be of sound-reasoning,, and since you have a spare jet to experiment with, I'd suggest trying enlarging it's hole to obtain near-about a 20% increase in area (not diameter).

Goodo, Bob. Thanks. I'll give that a try.

Kev