Dellorto PHM 38s

[Scout63]

I just hit the button on eBay and bought a set of new Dellorto PHM 38 rubber mount carbs.  They are for my next build - I’m going to rebuild a tatty 1980 BMW R100T into a stripped down fire road bike.  The carbs aren’t necessary for the project but they are so pretty. I wanted them.

My question is whether they would make good temporary bolt-on carbs for my G5 project, which will be back together before I really get into the BMW.  The VHB 30’s will clean up fine, but I figure I could play with the 38’s for a bit.  I’ve already built the motor from the bottom up in stock configuration, and am not going to get into it again.  Pipes are new LaFranconi competition and air filters will be K&N pods.  Am I foolish to mess around with the 38s with stock v1000 cam, valves and intake?

I’ll go back and read the Guzziology section on carbs again, but I was hoping to get some feedback. Thanks - Ben

[cliffrod]

I just hit the button on eBay and bought a set of (insert motorcycle words here).  The (similar motorcycle words) aren’t necessary for the project but they are so pretty. I wanted them.

These words should be a sticky.  More truthful words are rarely spoken or admitted...

[moto-uno]

  As something to play with and fine tune your carbs skills , why not ? Just don't assume the jetting will be all that correct .
The original ports and manifold will certainly restrict their potential , but hell , who doesn't enjoy playing with carbs ? .
Peter

[Rough Edge racing]

 Mikuni TM flatslides work very well on BMW's. they are compact and less than 175 bucks each new for the larger sizes. There is jetting info out there for BMW use...Not that that  Dellorotos are bad, just  saying............

[jwinwi]

NICE! Those are the carbs that gave the R90S its famous torque and HP. I'd save 'em for the beemer project and ride the Guzzi with VHBs. 

[John A]

NICE! Those are the carbs that gave the R90S its famous torque and HP. I'd save 'em for the beemer project and ride the Guzzi with VHBs. 

I agree, there would be a good bit of work to get them fitted up before you even get to the jetting. If you do get them on there, I’d start with the jets that came on the carbs. The carbs are a bit large and it will turn the bike into an unridable pig untill you give it the attention it’ll take. Stick with the VHB’s if you want to ride

[moto-uno]

  ^ Tell us , where's the fun in that ? Peter

[Scout63]

Good advice.  I’ll take them to the office and put them on my credenza with the oil pumps and broken gears that no one understands.  Then they will be shiny and clean for the BMW.  Thanks for the perspective.

[Rough Edge racing]

From my experience, flatslide carbs work better than round slides when sized larger than original.

[Scout63]

I received the PHMs today.  They came with metal double banjos, lever chokes, and a GORGEOUS Dellorto catalogue worthy of the coffee table.  I can’t wait to install and tune them, but that means buttoning up the Commando, sorting the starting problem on the /5, assembling the G5, and then disassembling and fully building the R100 they are going on. Hopefully Spring 2022.  At least I won’t be looking for carbs then, just thousands of dollars worth of other small parts.