1100 carb conversion

Hi all,I have an 1996 1100 cali engine that I want to put carbs on.I understand that 36 mm carbs would be ok but does anyone know if it would be ok with 40 mm carbs.It wont have the standard ignition either.Many thanksMark

Measure the inside diameter of the inlet stubs ir head as not much point putting 40mm on it if the clear passage is only 30mm

The standard inlet stub is 36mm.I can open this up to 40mm if necessary and blend it in to the inlet port on the head.I really wanted to know if anyone had done it and if so does it run ok.


I got the engine for next to nothing with no injector system or wiring loom.I’m going to put it into an old Spada frame I have knocking about I and have enough bits to build up a complete bike.Should make a nice enough bike for messing around on.

Sounds like a plan.
Don’t have the details but as a lead…
There were some German riders at an event last year who had done a similar conversion and used an expensive and very reliable ignition module mounted in the alternator housing.
The new engine/old frame idea has been popular in the UA for a while. Suspect at least some of the information you’re after may be available on the mainland European and American Guzzi forum.
Be interested in how it progresses
All the best

Ok. Seems a pretty interesting project. Since their are no FI bits carbs are possibly more cost effective to make it a useful lump.

I have not seen it done on a Guzzi, but I have seen it done on a BMW 1100Gs, using carbs from an airhead 1000, and it was a much nicer bike to ride and more economical, I would have thought it better to use 40mm carbs, if you want it to perform, but 36mm should be ok,

on the BMW, they needed a low pressure fuel pump as they struggled once the tank was low, with gravity and the flow through the tap, which was off an airhead!

can you not use a single carb?ianboydsnr2013-08-29 15:43:27

I will probably use the Silent Hektik ignition which as mentioned runs in front of the alternator.I hadn’t even thought of having to put in a fuel pump.I am hoping that the fuel flow will not need this.I would like to keep the wiring to minimum if possible and not have to many extra gadgets on it.According to Guzziology there was a version of the 1100 California that used 36mm carbs.I will use this info as a starting point.As for the single carb,Its a great idea but I dont have the time to be making up a manifold for it. Spare time is in short supply.

Carb size will depend on valve head diameter ultimately. Unless you have the large valve heads, then 36mm would be best.Believe me, the 36mm work extremely well on the 1000SPIII which has the mid valve heads.

My 1100 Cali runs 36mm carbs gravity feed straight from the tank via twin fuel cocks as standard if thats any help

Thanks Tris.That seems to be the sensible option and the one I will go with.Many ThanksMark

I should also have said that the fuel taps and carbs are connected via a cross connector so both taps can feed both carbs if that makes sense

Would recommend sticking to 36mm as the 40s are good for top end but suffer from fluffing when accelerating from slower speeds, best to keep it practical, if finding Dell Ortos is difficult nothing wrong with Jap carbs.

36mm PHF’s with the pump on the back edge …easy to fit and set up as has been said bigger carbs need bigger valves and will cough and splutter and not really help on a Cali.

Tis the old story …throw more in you have to let more out, so 40mm would need a valve job then the zorst looking at. Look at the choke size of the inj system fit carbs accordingly. Euro carb are very helpfull with jetting and set up.