float height on VHB30 CARB - T3

I have been rebuilding the VHB30 carbs on my T3 Cali and have noticed the Haynes manual advises the setting for 10g floats which I have should be 18.5mm whereas 14g floats should be 24.5mm.

Anyone know what is correct


I hoped that the Guzzi workshop manual might say, but no mention of float height.Look at the Dellorto Tuning manual, that has a section on floats, and gives the measurement.

VHB30 carbs on my bikes are set to 18.5mm

Thanks Keith there seems to be some inconsistency with float height settings in various workshop manuals which do advise 10g floats should be set at 24.5mm.

The Dellorto manual doesnt actually tell you what VHB settings should be

Mine are 10g and around 24mm (sez 23.5 but how accurate can you be really)

I have just done mine. I set mine to 23.5/ 24mm using a cardboard gauge in accordance with my yellow Guzzi manual.
I believe Haynes have it wrong. Mine were set to 18 and the bike was so rich nothing worked properly at all. Now it is set at the bigger setting it runs sweetly and my plugs are no longer sooty.
All the best,

Thanks David did anyone else have a problem with the 18.5mm float setting Im hoping to get the carbs back on the bike this weekend and would appreciate any comments

Amazing in 20+ yr I have NEVER done this at all on any of the bikes/engines or carbs… I have allus just stuck em on and without any interferrence from lil ol me they amazingly work…

The VERY best advice I was given many many years ago by an old mechanic was

"Boy…if it ain’t broke and it’s running well enough, why fix it! Change yon oil and the filters, check and change the plugs every year, and check yer points at the same time.

Check the brakes in between Mot’s and swap the shoes/pads and keep an eye on tyres, check them pressures every other fill up and you’ll be good!"

He was right.

I assume guzzibear that reading between the lines does this mean you dont know

Just lucky!
I bought some carbs from eBay and I assume the previous owner had adjusted them to the Haynes setting because the Moto Guzzi setting dimension is very clear.
All the best,

Nahh Will I dunno nuffin’ me…not at all… somehow the V1000 has rumbled over 250,000 miles alll on it’s own

I’ll go with the the 24mm setting and see if it solves the problem.

Let you know how it goes

This may be where the confusion comes about, if you look at the table on page 8, it becomes apparent that the height has nothing to do with float weight, it depends which model carburettor you’ve got. Before that it says:“Both types” - [of float] - " are usually available with two different weights:* a light float to obtain a low level (for two-stroke engines)* a heavy float to produce a higher level (for four stroke engines)" The implication therefore is that the height measurement is the same for both weights of float. The 14g float will then produce a somewhat higher fuel level than will the 10g float. There’s obviously not much in it because as I said mine runs 10g floats @ 23.5mm perfectly OK. Mixture can be a gnat’s whisker on the lean side (or was), but is easily compensated by idle screw setting and main jet size. HTH

set the carbs at the 23.5/24mm gave them a serious clean with carb cleaner as bike hadnt been seriously run for four years, used a can of compressed air to blow all vents and pilots and wow what a difference it has made engine running sweet through the revs and after even 20 mile run checked plugs and nice tan colour.

Thanks for everyones help

Brilliant news Willy. Glad we could help.
All the best,

There ya go