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I'm considering a 32phf carb for my 450 desmo as an upgrade from the VHB29 that is on it. It will have an 87mm piston, standard valves and a fairly straight through conti style megaphone. Any thoughts, advice? And jet sizes, or where to start?
Cheers.

The 32mm is the right size carb for road use. There is some info on here about it, and a good starting point would be the settings from a Ducati 860 GT, GTS, or Darmah, although be wary of the Darmah settings as they had anti-pollution carbs.

Thanks Duccout, If I have trouble getting a clamp type, would the ones with the rubber manifold sit alright on a modified inlet manifold?

Some people on this site have used a flexible fitting, but the big problem is clearance, because if the carb is moved away from the head by very much then the frame gets in the way. It is possible to fit the rubber sleeve over the original Ducati manifold, but as this is only 29mm bore it defeats the exercise a bit, but there are lots of possibilities if you don't mind a lot of fiddling. Try Road and Race in Australia.

The easiest way to fit a 32mm carb is to use an Amal, which bolts straight onto the head, and was a common fitment here back in the day.

I have two 450’s with 32 phf
Darmah jets and slides but change the atomiser to 262 instead of the standard 265.
Both are standard valves, and are 87mm bore.
The Scrambler has a clamp type carb, but you will have to try and get an air cleaner to fit due the the 450 frame gusset.
The RT has a rubber hose connection which doesn’t give as smooth a flow internally. You have to play around with an extra hose clamp to get the rubber coupling to sit properly.
There is no issue with the RT frame interference fitting an air cleaner

Graeme

Thanks Graeme

Hi Again and thanks for your help so far. I've found on line, the following for settings for 860 GT carbs:
Needle K6/2nd, Main jet 122, Pilot jet 60, Needle Jet 265AB, there is some discussion about a 70/2 or 60/1 slide, but the PHF's listed have either a 503 or 507 slide, what are these/ and the difference? Do they relate to the other slides?
Any recommendations for: idle jet, pump jet, choke jet , float valve? or are some of these going by other names?
Thanks again,
Bernard

Hi Bernard. The 860GT/900SS had the following settings: slide 70/2 ( these numbers relate to the cutaway and the pump jet activator, which is a type of ski ramp in the slide, and unless you are told otherwise, I would stick to this slide) pump jet 35; the idle jet is the pilot jet; choke jet 75; float 250 and float weight 1.10gr.

Have you tried to find a used carb from an 860/900? It may save you a lot, as long as it is not from an anti-pollution Darmah!

Hello Bernard
I disconnected the pump actuator from the carb top so they don’t pump.
They run just as well without the extra squirt of fuel that can play havoc with clean running.
Duccout, what is the difference with Darmah anti pollution carbs from a Darmah?

Graeme

Hi Graeme,

The Darmah anti-pollution carbs were set up weaker and had the pilot adjusters glued in place! The settings were: 60/3 slide, K16 needle, 62 pilot jet and 38 pump jet.

Colin