Dellorto question

[wirespokes]

I picked up a parts project last summer - a 75 1000, probably originally a convert. The engine and frame are most likely the only original parts. The majority of the rest are early LeMans. Of course it has the 30mm square slides.

The idea is to eventually convert it to phf 36, and I already had one of the carbs and a lever top. I found another brand new 36 that came with a lever top, so figured i was all set to go. However, there's one small stumbling block. These are the 36DD and DS.

I figured they'd be the same, but they're not. The parts that stick up into the throat are different. They don't show on the parts diagram so I don't have a name for them, but it's something of a shield for the main jet. It's the only brass thing protruding into the venturi where the needle enters the lower area.

My question is this: have you ever removed that part? What's involved? Does the carb need to be warmed over 200F to get it to drop out?

I know I'm opening a can of worms on this - but what jetting has worked to achieve good power and economy with this engine and PHF 36s?

Also, have you ever removed the gray anodizing? One is anodized, the other is bright aluminum and I'd like them to match.

[n3303j]

Doesn't D make it right hand and S make it Left?

[wirespokes]

Correct - D = destra (right) and S is sinestra (left). Now we can say we know Italian. :-)

Some bikes (like Ducatis, I believe) run both right side carbs, but since we can't get to the off-side and they're mounted on the left and right sides, ours are handed, in this case DD and DS. The first D is the series or some other designation.

[Scout63]

I think you’re referring to the needle seat. It should be a press fit into the carb body and can be gently tapped out from the top.  Smarter more experienced techs jump in anytime.

[wirespokes]

You could be right, Scout. Bing carbs have a name for it, and it often drops out once the main and needle jets are out. I believe it's also the main difference with the Lean-Burn carbs.

Hey, you've got some pretty cool bikes in the stable!

[hauto]

no protrusion is a 4 stroke cab. short protrusion is a 2 stroke carb. So I been told. Hardan Corp in Pa has parts and info.

[Guzzistaracing]

https://www.dellorto.co.uk/wp-content/uploads/2020/08/PHF-diag-image-map.jpg
What part are you looking for?

[wirespokes]

https://www.dellorto.co.uk/wp-content/uploads/2020/08/PHF-diag-image-map.jpg
What part are you looking for?

It doesn't show on that parts diagram either. It should be above #3, which I believe is the needle jet. #3 seats into that part which protrudes into the venturi. It's the only brass part you'll see when looking into the carb throat.

[Guzzistaracing]

It doesn't show on that parts diagram either. It should be above #3, which I believe is the needle jet. #3 seats into that part which protrudes into the venturi. It's the only brass part you'll see when looking into the carb throat.

The part you are looking for is part of the housing. It is as you say at shroud around the needle jet. This is not a part you can get as a spare part.

[wirespokes]

That's what I figured - not intended to be replaced. However, I'm sure it'll come out. Probably have to heat the whole thing up to 200F and it'll drop right out. Then with some precision filing, make it like the other one.

[Klinkhammer]

Atomiser bush?
2 links to Eurocarb.
There you will also find a link of how to remove it.

https://www.dellorto.co.uk/shop/dellorto-motorcycle-carburettors-parts/carburettor-parts/phm-parts/10338-dellorto-phm-phbe-phf-atomiser-4-stroke-bush/

https://www.dellorto.co.uk/shop/dellorto-motorcycle-carburettors-parts/carburettor-parts/phm-parts/phmphbephf-atomiser-bush/

US vs European (rest of the world?) bikes would have different bush. You can read more in this thread
https://wildguzzi.com/forum/index.php?topic=69557.0

[wirespokes]

Thanks for that Klink! So the bush isn't threaded, just an interference fit. That's good to know!

Unlike the Bings where the same part exits out the bottom, these exit the top.

It seems to me, heating the carb to 200F upside down, the bush should just fall out. I think I've got enough data now to make this work. Thanks again!

[centauro]

As I remember reading in Guzziology about the types of PHF36s, the ones that have the shrouds are the so-called "Lean-burn" models, which were used on US-spec LM3 and Swiss market models. In addition to the shrouds, the jetting is also slightly different than the regular PHF36.
No idea if or how the shrouds are removable; my late SP/NT only had regular PHF 36s, but I am sure they can be pressed out with care, but in order to have a matched PHF set (DD and DS) the jetting in the shrouded model should be checked and changed to the same parts as the other PHF, I would think.

[wirespokes]

Thanks again, Klink for that valuable data!

The atomizer bush, as they call it, is pressed in from the top.

I made a tool from an old atomizer. The first try didn't work so well and started splitting the end of it. So I cut it shorter and turned down a piece of steel rod to fit inside it, with the same outer diameter.

Tapping on the tool didn't budge the bushing. A propane torch got the carb smoking hot, and it still wouldn't budge. Heated it some more and this time didn't tap with a brass hammer, I dropped it on the tool and held it - over and over. After five or ten hits it budged and finally came out.

The internal threads of the bushing are M7 x .75. A screw or bolt will work in this case.