450 Mark 3 engine rebuild and cam change

[machten]

Just finished rebuilding the 450 Mark 3 engine and installed it today. I took the opportunity to replace it's white camshaft with a green & white camshaft. Distinctly different characteristics apparent already, but I've still to tune the VHB 29 carb for it. Anyone have any guidance on VHB jetting, etc for a 450 with a G&W camshaft? I'm still using the stock Silentium exhaust.

Kev

[Jordan]

Some data for 450s from the Ducati workshop manual supplement for widecase models.

[machten]

Thanks for that Jordan. I'm running a 50 pilot and 135 main. The 50 pilot I think will tune with the mixture screw (it's not an idle problem, it idles fine - it's transition to 1/2 throttle and also wrapping it on seems to starve...main might be a little light on perhaps. I'm hoping that I don't need to find/produce a different slide.

Kev

[DewCatTea-Bob]

[quote= machten ...
" Anyone have any guidance on VHB jetting, etc for a 450 with a G&W camshaft? "

____ To get the tuning as close as Ducati had, you could simply copy the jetting Ducati chose for the 450DESMO-models, since all the cam.specs are pretty-much the very-same for the std.DESMO-cam and the G&W.cam ! - (In fact, the standard/Blue&White DESMO-cam's [opening-lobe] specs were based upon the 250F1/G&W.cam !)



" I'm still using the stock Silentium exhaust. "

____ Then expect low-end performance that's markedly inferior to that which the white-cam provided, and about an even-match at higher RPMs, (although RPMs above 5-grand will not be so dead as with the white-cam).
__ To get your G&W.cam equipped 450 to come-ALIVE (with it's notably superior performance-strength), you need the 'special' 450 shorty-megaphone (which makes a BIG-difference) !
Your stock 450's Scrambler Silentium-muffler is too restrictive in combo with the G&W.cam,, so consider a less restrictive alternative, such as a glass-packed straight-through shorty-silencer.


Hopeful-Cheers,
-Bob

[DewCatTea-Bob]

[quote= machten ...
" it's transition to 1/2 throttle and also wrapping it on seems to starve... "

____ That's rather common and is mostly due-to the reduced intake-tract air-velocity that the wilder cam causes.
A less restrictive exhaust-system can help reduce that lack of response, but you may have-to get used-to most of that acquired characteristic.
__ Have you not ever ridden a 450-DESMO, so that you'd know what to expect in such regards ?


" I'm hoping that I don't need to find
a different slide. "

____ In an attempt to address the 450-DESMO's rather poor response-issue,, I once installed a brand-new 29mm 'square-slide' with Dellorto's added pumper-setup (as was standardly employed on 1973 850-MotoGuzzi models). _ And instead of curing what I had assumed was a temporary lean-mix issue (when suddenly grabbing a handful of open-throttle), the usually resulting dead-response actually got much-WORSE instead !!
So I gave-up & ended-up reinstalling the original 29mm.Dellorto and settled for it's regular throttle-response lag, (and just raised the needle-valve [to it's lowest notch]).


Dukaddy-DUKEs,
-Bob

[machten]

__ To get your G&W.cam equipped 450 to come-ALIVE (with it's notably superior performance-strength), you need the 'special' 450 shorty-megaphone (which makes a BIG-difference) !
Your stock 450's Scrambler Silentium-muffler is too restrictive in combo with the G&W.cam,, so consider a less restrictive alternative, such as a glass-packed straight-through shorty-silencer.

I have this exhaust I originally planned to put on the 250 twin filler, but changed my mind as I've grown to like the look of the stock old school Silentium "bullet" on it and it performs quite well. I'm still to get the 450 road registered in Australia (it was one I used in Europe over the last 4-5 years) and planned to leave the stock exhaust on there until I'd done that, as unmodified vehicles over 25 years old can qualify for very much reduced licencing fees here. Regardless, I'll fit up this exhaust and see what happens.

Small.jpg

__ Have you not ever ridden a 450-DESMO, so that you'd know what to expect in such regards ?

Yes, but those friends 450 Desmos that I have ridden have either had the exhaust pictured above or shorter megaphone style (very loud!). I can't say I've noticed the same characteristics I'm experiencing with any of those 450 Desmos, but my riding of them has been of limited duration and conditions.

Thanks for all the info to all.

Kev

[machten]

Well, after fitting the Conti style pipe, everything is verrry sweet with the G&W cam. It pulls very well even from quite low down. I can't push it up too far yet, only done 70km since the rebuild, but that pipe sure makes one hell of a difference. The jetting seems fine for the moment, I'll see how it looks on the main jet after I can take it up the revs a bit.

Thanks to all.

Kev

[machten]

A good squirt today of 120 km on the break in plan. The old girl was cracking nicely...(And yes I know the exhaust side passenger peg had loosened, but I had expected it and had a 17mm open spanner with me!)

IMG_1659 (1024x768).jpg

Kev

[Ventodue]

Che bella!

Sun's shining, I see

[machten]

Spring is in the air Craig! (Like you have any cause for weather complaint!!!)

Kev