T3 accelerator pump

[RichCutler]

Hi all...

I'm rebuilding the VHB30 carbs on my newly acquired T3 and have just discovered that one of the carbs is missing its accelerator pump valve assembly. So, two problems:

• the pump piston (#7831) is out of stock everywhere (I'm in the UK)
• even if the piston were available, the three valve parts (piston, valve, ball) cost over $40!

I've heard that some people remove the VHB accelerator pumps. But I can't find info on this. I'm tempted to just remove the other pump...

• If I remove the remaining pump so they're both missing, what effect will that have? I assume Guzzi put them in for a reason!
• If I remove the pumps, do I just take out the (remaining) valve assembly? No other changes?

Even better would be if someone has a pump assembly they don't need!

(BTW, not my first Guzzi - 20 years ago I spent a serious amount of money on rebuilding a Le Mans 850 that used blow modern bikes into the weeds off the traffic lights. I sold the bike over a decade ago but kept the website up as people kept asking about it: richcutler.co.uk/guzzi/index.html

 

[john zibell]

The pumps squirt fuel as you raise the slide/needle to help with acceleration. Removing them may make the bike a little sluggish. Have you tried contacting a breaker? They may have what you need. Also check e-bay. I found this from the Netherlands.
ebay.com/itm/DELLORTO-HOUSING-ACCELERATOR-PUMP-843000320000-GU843000320000-GU84300032-8430/142571902345

 

[RichCutler]

Thanks, John. I think that's from a PHB (Le Mans) carb. Anyway result: someone's offered to send me the valve assembly!

I'd still be interested to know how a Guzzi performs without the pumps ... just curiosity!

 

[Moto-Uno]

It will have throttle response similar to 70's Triumphs and BSAs . In other words to kill the motor
simply yank the throttle wide open at idle . On the highway expect very little difference ! Peter

 

[Amboman]

If you just need the "piston" assembly, I have several used and can send you one.

 

[RichCutler]

If you just need the "piston" assembly, I have several used and can send you one.

Thanks for your kind offer, Charlie. However, someone's already popped one into the post to me, so I'm sorted now.

 

[Larry H]

Hi All,

In the reinstatement process of my LM1 1977, yesterday I began to dismantle the carburettors (Dellorto PHF 36 B) and unfortunately discovered that both housings for the accelerator pump had cracked and more or less disintegrated. See attached photo.



The other parts of the carburettors are in a pretty good condition, just need a bit of cleaning. The alu material of the pump housing must be very different from the carburettor main part material.
I looked a little on the internet and it seems as if the housing is not available as spare part, nor a complete accelerator pump assembly?
Would anyone know where I could buy two pump housings or two accelerator pump assemblies?
If they are not available, I guess there are three options:

1.
Run the bike without accelerator pumps. I suppose I would simply remove the pump lever and plug the hole where the pump plunger runs? Wonder what that would do to the acceleration?

2.
Try to get new or second-hand PHF 36 B's.

3.
Replace the PHF 36 B with another type of carburettor. What would be a suitable alternative?
I remember years ago someone recommended to replace the PHF 36 B with a Lectron slide type carburettor but I think they had to be modified to to fit. They were made in Michigan so even if they are still available they would probably be fairly expensive.

 

[john zibell]

Go to guzzino.com/decapa.html The pump housing is available.

 

[Amboman]

Also: dellorto.co.uk/product-category/dellorto-motorcycle-carburettors-parts/carburettor-parts/phf-parts/

Same carbs were used on Ducatis: ducati-gowanloch.com/

 

[Larry H]

Thanks Guys, I will contact them.

 

[Larry H]

Got the pump parts from Gowanloch. Their workshop is only 17 km from where I live