Dellorto PHBH30AS

[Wally Anderson]

I'm assembling a 1965 250 Monza, the engine is stock. I purchased the bike taken apart in many pieces packed in boxes. This Momza is a rehab project after having a stroke last year. I didn't get a carb so I purchased a Dellorto PHBH30AS carb from Bevel Heaven. Steve wasn't sure of the jetting for a stock 250 so my question is what should I order? Idle jet, main jet and needle?

[DewCatTea-Bob]

" I'm assembling a 1965 250 Monza, the engine is stock. "

____ Then the cyl.head's intake port is only 26.5mm, and I'd suggest using a carb no larger than 27mm.


" I didn't get a carb so I purchased a Dellorto PHBH30AS carb from Bevel Heaven. "

____ So how the heck do you intend to get that large carb properly mounted to your otherwise stock-DUKE, Wally? _ Have you already got that less than simple task all planed-out? _ If so, then how about telling us all how you've planned to manage that tricky project?


" Steve wasn't sure of the jetting for a stock 250 so my question is what should I order? Idle jet, main jet and needle? "

____ If I were to ever take-on such a carb-to-DUKE project, I'd choose to start-out with the same sizes as was stock for the Ducati 500-twins.
If I knew what any of those sizes were, I'd tell you now. _ Guess you'll have to ask Steve, or somebody.
__ Or you could get a more suitable carb. ...
I have a rebuilt stock-250Monza 24mm-carb which I'm thinking of listing on eBay if I get any excuse to do so. _ So if interested, please let me know.


Dukatdy-DUKEs,
-Bob

[Wally Anderson]

Hi:
When I said STOCK I was talking about the engine, the tank isn't stock (custom aluminum from Terry Baker in Wales) as is the hump back seat. I shouldn't have a problem of space under tank.
PS: Unfortunately Terry Baker lost his battle with cancer last month. I believe I received the last tank he formed.

[DewCatTea-Bob]

" When I said STOCK I was talking about the engine, the tank isn't stock
I shouldn't have a problem of space under tank. "

____ I suppose that it's possible that an older-type of Monza-design fuel-tank could've caused a clearance-issue with the use of that large carb but, it wasn't the tank that's the concern ! ...
The backbone-tubing of the frame already occupies the space where the choke-cable fitting and left-side screw-bulge for the slide-cover (of that over-sized carb) ought to be positioned into (for a proper fitting to a stock-cyl.head),, thus you must concoct some kind of extensive manifold set-up ! _ Which is likely pretty-much what I was hoping you'd show & tell us about, of how you've planned to manage fitting that large carb to your stock-cyl.head and yet also avoid any other possible additional clearance-issues at the same time, as well.
__ Many others have intended to install that same large model-type of Del.carb on their (non-R/T-type frame) DUKE, and later then found such clearance-issues to prevent it's proper fitting & use,, and most of the few who have continued further-on with their oversized-carb project and managed some way to get around most of their fitment-issues, have not been very forth-coming with telling of the exact details on how they finally got that oversized-carb mounting-project accomplished to their satisfaction.
So I'm still hoping that you've got it all worked-out and are also willing to tell us how you managed to get such a fairly challenging project all nicely done-up.


Hopeful-Cheers,
DCT-Bob

[Wally Anderson]

how they finally got that mounting-job done to their satisfaction.
So I'm still hoping that you've got it all worked-out and are willing to tell us all how you managed to get such a challenging project all nicely done-up.


Bob:
When I get the carb issue worked out I'll send pictures and explain how it worked out. Steve at Bevel Heaven sells a 2 piece manifold that the customer welds at the proper angle. Right now I'm working on the wiring, I'm using a Boyer Electronic Ignition. The carb will be the next and final project. I have been working on this cafe racer project for over a year, other than the frame and forks everything else is new. I can only work about two or three hours a day then the old body gives up. I sold my 916 and am also selling my 06 Sport Classic as I'm unable to ride anymore.
Cheers,
Wally

[Wally Anderson]

other than the frame and forks everything else is new

Sorry, other than the frame, forks and engine ALMOST everthing else is new.
Wally

[DewCatTea-Bob]

" Steve at Bevel Heaven sells a 2 piece manifold that the customer welds at the proper angle. "

____ That sounds like it will be quite helpful for the fitment-job, (providing the welding goes well) ! _ And while those parts made for the intended manifold should be relatively cheap to produce, I'll bet they don't come too cheaply!?
__ Since the chosen carb has a 30mm port, what's the inner-diameter of the manifold-port and how does it get properly matched-up to the cyl.head's much smaller intake-port?
If the manifold's port tapers from 30 down to 27mm, then that should work nicely for you but,
I'm betting that it's port-dia. is straight-through at the same 30mm,, right? _ If so, do you plan to port-out the cyl.head's 26.5mm intake-port some planned amount? _ If not any at all, then I can only see that over-sized 30mm-carb HURTING -(as opposed to helping) your 250cc-engine's OVERALL-performance, (compared to a 27mm-carb on a stock Monza-engine), with stock cam. _ (Sorta like putting a 4-barrel carb on an otherwise unmodified lawnmower-engine.)
__ Since you can no longer ride (like myself), I'm assuming that you're really just interested in building a bad-ass LOOKING cafe-DUKE.(?)


Fun-Cheers,
-Bob

[Wally Anderson]

Since you can no longer ride (like myself), I'm assuming that you're really just interested in building a bad-ass LOOKING cafe-DUKE.(?)

Bob:
When I sold my 916 I decided to turn the money around with the 250 bitsa project and it hasn't been difficult spending the cash from the sale.
I've a friend who owns a bike shop who will help me out if I can't deal with the carb. He's a WERA racer and so far has kept all my Ducatis on the road for the past twenty years plus his various race bikes.
Wally