T3 Guzzi Carbs

Has anyone put 32 mm Amals on a T3, if so was it worthwhile, just looking for a tad more power, would open the inlet port to suit .


Amals were a popular swap in the early to mid 1980s.
I suspect that with the development of better understanding of how DellOrtos work it may be possible to get better performance from jetting and needle position.
Working with a friend on fitting a 36mm to his Enfield has been a revelation.
Best performance I got from T3s and T3 Cali was K&N pods, free breathing but not open pipes and adjustment to the carbs.
This being done once the baseline of tappets (noisy!) and timing was sorted.
Be interesting to hear/read others’ thoughts.
Good luck

We’ve got 32 ml amals on a spada motor Chilly…work well…many years ago I out 32s on a V50…superb…I blew it up eventually cos we couldnt raise the gearing…so it had prolonged bouts buried in the red !

Already got K&Ns fitted thanks Steve, carbs are the square type vhb’s, have some round 30mm Dell flat tops i can put on, but fancy a bit more free flowing power, not much, just a tad more get up and go which i thought some 32mm might do without to much hassle .

Kate, i presume you have matched 32mm manifolds to fit the Amals + K&N pods ?
are they the Mk 2 type with rubber manifolds or Mk 1’s ?
So many questions, sorry :blush:

Thanks for the replies

watching with intrest for the spada build
as i have
30 mm original square
30 mm brand new round conversions
36mm brand new rounds flat top
36 mm second hand high top

one thing i found out to late was the 30 mm round conversions i bought are exactly the same carb as i have spare off the V65 just supplied with a bigger main jet

Not much input on this subject Ray :frowning:

What i have found is RaceCo reckoned that bored out 30mm to 34mm worked well on T3 and Spada without anymore tuning, just not sure what they did to the inlet manifolds tho ?
it just says manifolds made to suit ?.

Fitted a pair of 32mm DellOrtos to a Convert, they came off a Laverda Montjuic and went straight on, no rejetting or fiddling required, much crisper pick up, a bit more top end and fuel consumption the same. Wish I could find some more.

Slightly off topic, anybody got experience of fitting 36mm round slide non-pumper carbs to a Spada motor?

no bonus in fitting to a Spada as they are only the smaller valves


Race Co reckoned a 34 mm carb (30mm bored out) was a good upgrade on a T3 or Spada, would 36mm would be too big then (overkill maybe ), he doesn’t mention 36mm, so maybe that answers the question but i thought i’d ask anyway ?

A friend of ours had a T3 which came with 36 pumpers on it…and it wasnt up to much…suggested he put the originals back on…sweet…
See you sold the bike btw Chilly…x

Yep! bike went to someone who i think will get a lot of fun out of it, he’s very enthusiastic + his Dad had Guzzis when he was a Kid so its in the blood :sunglasses:

I’m sure your right there Kate 36mm pumpers would be overkill, still going to have a go at boring out my 30mm to 33/34mm just because i can + it makes life more interesting this time of year :smiley:

Can always fit the originals back if its a failure, have a good time at the MZ Rally x


Many years ago (when I was young and even more stupid) I put 36mm pumpers on my very ratty T3 and I’m convinced it was a big improvement.

I was thinking of putting some 36’s on a spada engine I have.

Any more on this subject???

I was hoping for some info on this by folk who have dabbled, i’ve asked on the other site as well, but so far nothing much to report :confused:

Surely there must be folk in the Club who have tuned their small valve big block motors ?

last small valve i worked on untill it had done 30 mileused to pop and fard for gold medals and it felt like you had put kangaroo juice in it - direct swap to 30mm and it ran fine put the 36mm on a lemans and that run fine so my conlusion was they were to big

Thanks Ray, still looking for input on boring out 30mm to 33/34mm , looks like i’ll just have to find out the hard way. :frowning:

Ok then folks ! just took off the 30mm alloy manifolds on my T3 and to my surprise the size of the inlet duct to the valve was approx 33.75mm on both heads, have they been opened up in a previous life from 30mm or is that the standard size ?

Looks like my enthusiastic plunge into opening up the 30mm carb bodies to 33/34mm will be on hold, not quite as simple as i once thought :laughing: