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Mounting the Weber, I did a last check on content (I did mount the 34mm chokes) when I noticed the manual says the "idle air jet" has a size 130.
Sorry, but where is this jet (how does it looks) and how can I see the size (130)?
I have dismantled/overhauled the completely but have I missed something?

Regards,

Frank

Frank in the middle of the carb body on either side under a brass slotted screw right below the carb top There is an o-ring which seals the screws to the carb body. The jets are held in place by the screw and the size is imprinted on each jet. Number 25,26,27 in the diagram

Hi Higgy

Thanks for the info but those are the idle jet items and the Paso workshop manual mentions also an idle air jet (size 130 ?!).
This one I don't know, I know the screw (item 6 on the page 4 of your Weber mod. piece) but I can't find a number/size.

Anyway I did mount the 34mm chokes you advised on the otherwise, although overhauled incl. new buttervalve spindle, completely standard Weber.
I wanted to fit 2 F21 emulsion tubes but these were almost impossible to obtain and 1 source asked $90 for the 2 (excl. P&P).
So this will be the base for later tuning.
I do however mount a vacuum fuel pump.
The float level confused me a little: the Paso 750 workshop manual says 46mm but I read a lot about 42mm (maybe for the 906 .... ?).

Also I was not able to find me a fresh (non cracked) carter venting hose (pn 037095530), does anyone know if it is possible to make a bend in a straight rubber/nitril hose without collapsing/closing the tube/hose?

The K&N airfilter (DU-900) does not fit that well, maybe due to the air filter housing (750 version is poorly manufactured, maybe it's better to mount a 906 version).

Frank

The 906 airbox has the breather hose connected to the front bottom instead of the front.
There are breather hoses that look similar. You'd have to ask the sellers for the inner diameter, overall length and width of the elbow. There's probably something out there you can use. Maybe:
https://www.ebay.de/itm/142577567260#shpCntId
https://www.ebay.de/itm/142792124152
https://www.ebay.de/itm/Moto-Guzzi-BREA ... SwR4dbdZjc

Thx Gerhard!

Good tip: Guzzi dealer!

Any advise on which float level I should use: 42 or 46mm?

Frank

The float level confused me a little: the Paso 750 workshop manual says 46mm but I read a lot about 42mm (maybe for the 906 .... ?).

yes, P750 46mm, 906 42mm

generally speaking the float level when adjusted correctly should be level with the carb top when the needle just contacts the seat. My eyes are older these days and I find a cheap pair of diopters(reading glasses) from the local drug shop most helpful in seeing when the spring on the top of the needle just starts to compress. This is the point where the top of the float should be level with the carb top.


The jet I think you refer to is the needle valve used for fine tuning the idle air jets. When the DCNF was new they came in three different tapers. Yes they had numbers to order but no markings on the needles. Good luck finding them with anything other than the "standard" taper these days

Weber DCNF Idle Mixture Screw, 64755.007 Alfa1750 still has them for about 5 bucks plus shipping(9-2018)

Higgy, thanks I'll adjust the float to be level with the top of the carb.
Makes sence because if not level my next question would be which part of the float should be 46mm from the top.
If I adjust it level with the top it measures 42mm, so I will keep it there.

Concerning the idle air jet, happy to understand where it came from since I document all the changes I've made and the "300" made me doubt if I forgot something or not.

And I started using reading glasses 10 years ago, unfortunately (have difficulty reading the sat nav when riding my bike ).

my next question would be which part of the float should be 46mm from the top

That's simple. See pic below. Ignore the 48mm that is for the metal floater not the plastic version. The float level is measured as shown or with the cover at an angle. It's usually not measured upside down because the weight of the floater could aready bend the tongue and falsify the measurement.
Imo 42mm is too high. You risk the carb to overflow and the engine to run even richer.