su/stromberg carb on a guzzi le mans

[WAYNE999]

Hi I've been away for a bit but her we are again
I've recently re-commisioned my guzzi trike after a long lay up . It's always ran really rich but it is running the wrong carbs for the bike and the only place I can find a pair of the original phf carbs are gutsi bits in west yorkshire at £125 a side for re-build.
I'm not bothered about being the fastest thing out there as long as it runs well and pulls away cleanly.
So I thought about making up a manifold and fitting a su or stromberg carb which are easier to work with and a lot cheaper and a bit of achallenge does anyone have advice regards jetting etc.
Also in the shed I have a pair of strombergs from a 70's Triumph 2000 with a re-build and correct jetting would one of these do the job

[the coppersmith]

I think any carb will do the job, its just getting it right, you can over carb though, air has to reach a speed as it passes through, to big and the air is just to slow. Found this out on a rolling road session recently.

[Olds]

Also in the shed I have a pair of strombergs from a 70's Triumph 2000 with a re-build and correct jetting would one of these do the job

Think those would be CD150 carbs. Possibly a bit big. I'd look for an  1.25" SU or CD125

[morrag]

Something like this then? I'm using an 1 1/2" H1F4 SU on my 3 Wheeler project, supplying a Honda GL 500 "V" twin motor and it runs fine, although Coppersmiths point re air speed is of course correct and relevant, however I just happened to have this SU, so....if it proves "grumpy" low down I shall swap it for a. 1 1/4", so we shall see. The Strombergs should be ok, or rather one of them as that's all you will need, new diaphragm and a good clean, make sure the main jet is centralised, and.............suck it and see , what fun!! cheers, Morrag

[morrag]

This shows my Honda "V" twin motor with an SU fitted......................

[WAYNE999]

The photo of the guzzi engine is exactly what I had in mind.
Thinking of re-building one of the pair I have and rapeing the other for parts making a manifold and see what happens
Still have to mess about with ignition timing before I start as it's only running 1 and 1/2 cylinders
By the way I love the copper plumbing on the cx engine

[minimutly]

A 1.5 inch his su (late mini, metro 1000) would be my choice, nice compact carb, not too big, and a huuuuuge range of needles available. Not saying a stormberg won't work, but they are not so well serviced with needles and spares.
Huw

[Farside]

My GS850 with an SU HIF38. I had a 44 on it for years, but gasflow was rough at the lower end, so a couple years ago put this on - pulls like a train now up to 90+mph. The manifold (ex Avenger with 'zuk flanges) is good for 115mph in cfm terms, which the 44 could do.
Yellow spring, ADR needle, 30mm thick K&N pancake, stub stack. The combo of all those things works on this engine.


An overview of the installation, with daft little pancake filter - thrown in the bin, as it was strangling the thing...




The K&N element, which had been on the HIF44 from day one...only reason I didn't re-use it was lack of fitmentalityness; soon solved that.

su/stromberg carb on a guzzi le mans

[Manky Monkey]

That's an interesting set-up.