Weber Carb settings

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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Fireypete
Posts: 25
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Weber Carb settings

Post by Fireypete »

Hello all
I've found a a couple of articles, one referred to a swap to a 40 DCNF, I'd rather keep it stock. The other lists:

150 Mains
F27 Emulsion Tubes
60 Idle Jets
4.5 Auxiliary Venturies
Float at 43mm

All double Dutch to me, but the Weber shop will.understand and have the parts. I can have those parts put in as part of the overhaul. Also, thoughts on the float? Should I just replace it?
Pete
Kiwi Rider
Posts: 45
Joined: Thu Sep 05, 2024 6:47 am
model: 750 Sport
year: 1988
Location: Southland, New Zealand

Re: Weber Carb settings

Post by Kiwi Rider »

Hey Pete, I had a weber specialist overhaul my carb but it's still fluffy and hesitant getting back on the gas coming out of a corner. They suggested increasing the size of the pump jet but it turned out the previous owner had already done that tricks so I actually decreased it to a .35 (I think .25 is stock), but it didnt help. I'm assuming they set my float height to the stock setting, but I have not checked it. I will get back to this issue latter on when I get the bike mobile again. I want to stick with the stock carb too esp as I spent $700 getting it reconditioned!
Mc tool
paso grand pooh-bah
Posts: 1974
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: Weber Carb settings

Post by Mc tool »

700 bucks ! far canal ! did he gold plate it ?
As fa as I know nobody has got that weber to behave properly on the Paso . There are threads and discussions here where peeps have tried .
Dont get me wrong , Im not trying to piss on your campfire . Im sure there is the right set up , just seems elusive . Mostly they are pretty good but the hesitation just getting off neutral throttle seems to be a hard thing to cure . Bit like meeting the most awesome chick in the world .....only to find out she farts in bed , you have to figure out if you can live with it .
Before you get to involved in tuning the weber I would check cam timing as this was a bit hit and miss from the factory and its not unheard of for there to be 8deg difference between cylinders . I dunno just how much difference this will have on tuning if your going to assume both pots are the same ( and they might be ). I have been looking at the Chinese type FCR's , some good reviews , and I bought a whole carb for my Suzuki LTF off the same guy and apart from both the throttle and choke cables needing a bit of minor adaptation it bolted straight on , started and ran just fine .
I wish I was young again............Id be heaps smarter than last time
Fireypete
Posts: 25
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Re: Weber Carb settings

Post by Fireypete »

Hi guys, I will have a chat to Weber Performance, not far from me. A fella who works on these for a living may have some suggestions. I have found and written down a couple of set ups and will see what he thinks of those as well.
When I get the bike running I won't use it much as I want Brad to do a service. I will get the valve clearances done and definitely ask to check timing. The belts look new but I'll put new ones on to be safe. I'm booked in for Nov. 24th. Brad reckons things are going a bit slow as he is only booked out 3 months in advance...its usually 5!
Mc tool
paso grand pooh-bah
Posts: 1974
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: Weber Carb settings

Post by Mc tool »

Im pretty sure it was Brad that I got my adjustable cam pulleys from .
I wish I was young again............Id be heaps smarter than last time
Kiwi Rider
Posts: 45
Joined: Thu Sep 05, 2024 6:47 am
model: 750 Sport
year: 1988
Location: Southland, New Zealand

Re: Weber Carb settings

Post by Kiwi Rider »

Mc tool wrote: Sun Sep 14, 2025 9:29 pm 700 bucks ! far canal ! did he gold plate it ?
No but he did bead blast it! :wink:
Theres was heaps wrong with it, a lot of bits replaced and time spent on it. It came back looking like new.
Hey what site were you looking at the Chinese FCR's on? Is there room between the cylinders for two carbs? I know the F1 has the rear cylinder carb on the opposite (rear) side.
Mc tool
paso grand pooh-bah
Posts: 1974
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: Weber Carb settings

Post by Mc tool »

Ali express and Temu .
Bead blasting ? , did they come up OK , just that I have bought a pair of Delorto PHF36's for my Guzzi and they do need some attention cosmetic wise but I didnt want to polish them . I thought maybe soda blasting .
I wish I was young again............Id be heaps smarter than last time
Fireypete
Posts: 25
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Re: Weber Carb settings

Post by Fireypete »

Regarding carb float. Thornbury Carbs recommend the poly plastic float for Ducati's. That's what the bike came with. Deswoodau found the same.
Weber Performance didn't know about plastic, as they usually come with brass, so I'd be guided by Thornbury. My carb has been tinkered with I think
It has main jet 145
Idle of 50
Emulsion f27
When I get it all back together I'll let you know what it has
Kiwi Rider
Posts: 45
Joined: Thu Sep 05, 2024 6:47 am
model: 750 Sport
year: 1988
Location: Southland, New Zealand

Re: Weber Carb settings

Post by Kiwi Rider »

Mc tool wrote: Mon Sep 15, 2025 7:29 pm Ali express and Temu .
Bead blasting ? , did they come up OK , just that I have bought a pair of Delorto PHF36's for my Guzzi and they do need some attention cosmetic wise but I didnt want to polish them . I thought maybe soda blasting .
Possibly soda blasting, couldnt be sure, but looks good
IMG_1351.jpg
IMG_1351.jpg (131.5 KiB) Viewed 389 times
Mc tool
paso grand pooh-bah
Posts: 1974
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: Weber Carb settings

Post by Mc tool »

That does look good :)
I wish I was young again............Id be heaps smarter than last time
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