Carb Pro's and Cons

Hi All, pretty sure this would be covered but couldnt find it. Im considering either going to a single carb(premier) and a 2 into 1 manifold or should i just get a pair of Premiers. The old carbs are fingered and it shits me to tears not being able to tune it properly. Going on a 73 750...

Thanks in advance.

Ross

Assuming your 850 currently still has dual carbs, I'd go with a new set of Premiers. You've already got all the hardware, manifolds, air cleaner, cables, splitters. You can buy a set of Premiers for $350, literally just bolt them on on and your 850 will be running like God intended. Easy-peasy.

With a single Amal you'll also have to buy a 2-1 manifold, new cables, air cleaner, fuel lines, and you'll probably have to experiment a bit with jetting if you run a single Amal. Cost will probably be a wash.

I know a lot of guys run single Mikuni's and they really like them. I haven't heard many people with a single Amal on an 850.
I had a single Mikuni on my 850 and it's performance was flaccid (I know, apples and oranges). Yeah, it's easier not having to sync dual carbs. But it's worth the effort in my humble opinion.
Just my $.02.

mschmitz57 said:

Assuming your 850 currently has dual carbs, I'd go with a new set of Premiers. You've already got all the hardware, manifolds, air cleaner, cables, splitters. You can buy a set of Premiers for $350, bolt them on on and your 850 will be running again like God intended.
Easy-peasy.

With a single Amal you'll also have to buy a 2-1 manifold, cables, air cleaner, and you'll probably have to experiment a bit with jetting if you run a single Amal. Cost will be a wash.

I know a lot of guys run single Mikuni's and they really like them. Haven't heard many people with a single Amal on an 850.
I had a single Mikuni on my 850 and it's performance was flaccid (I know, apples and oranges). Yeah, it's a lot easier not having to sync dual carbs. But it's worth the effort in my humble opinion.
Just my $.02.

Click to expand...

+1
A single carb set up will lose some power due to curves the mixture has to go around as not just the reduction in overall throttle size being reduce by lowering the number of carbs

Thanks Guys.

Its a 750 but same same.

Ross

I have a single Amal Mk2 32mm on my 850 mk2.
It goes well but in my opinion starts to lose out over about 5000rpm.
Doesn't need touching, tick over is great, doesn't seem to use a lot of fuel.
I will be putting a pair of premiers on though in due course. After all thats what it was designed for.

Yes, My Atlas came with a single Amal 930. Started easily and idled well. Never touched it.
But the performance was way off from that of my 750 Commando. I've just completed installing a set of 930 Premiers.
Snow has just melted here so I haven't started it yet. Time will tell.

Leaning towards the twin carbs. Im in Aus, can anyone suggest a close supplier. Just looked at 930 series from rgm, postage was 140 pound.......

If you contact Jerry Doe, the owner of this site, he may be able to help you. He was supplying new Premieres all set up as required for 750 or 850 and the price was excellent.
Jim Comstock posted some dyno info re the ability of a single Concentric to flow fuel. He found that they only have enough fuel flow to produce 30-35 HP. This isn't a problem with a pair mounted, but will really cut power with just a single.

Glen