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Im going to Change my Edelbrock 1901 to a Holley but dont know what model.
Boss Hoss Germany only changes to 750 double Pumper. I guess, that a 650 double pumper must be enough and ideal solution, if I want something similar to the Edelbrock ((I dont want more power or better acceleration...........)
But there are different models of the 650er with different properties. What would (did) you prefer?
https://www.summitracing.com/int/search ... cation=int

Sorry I can't help, I have a 350 with Holley but Vac Bagged & sealed her up this morning for the Winter...

Gladiator, IF your BH come from the factory with a 750 CFM 1901 carb and BH Germany only replaces it with a
Holley 750 CFM carb, WHY do you think a 650 anything is gonna be better in any way??? IF you have been following
any of the carb issues posted here you might want to have Carb Mike do his Stage 2 modification to your 1901 or
buy one here and have it sent to you???

Paul H

We changed out the 750 Edelbrock on a customers SB bike to a 650 Quickfuel. We find the bikes are all overcarbed here.

His SB bike was upgraded in HP to over 500hp at Mountain and even then the 750 was too much carb.

I have used the CFM calculator on the Summit site:

https://www.summitracing.com/expertadvi ... calculator

Using 350 ci at 5800 RPM yields 499 CFM street and 646 race.

I agree with Barry that a 650 CFM should be a plenty.

Again as a complete novice when it comes to these engines, what exactly is wrong with the 1901 that everyone wants to change and what does carb mike do to it and how does it improve things

I'll 3rd that the 750 with mech secondaries is way too much carb. This is a little baby motor, needs a little baby carb.

@Knockdolian
My 1901 runs great!! The second Stage is like starting a turbine!! But for about 60 000 km, the bike is starting very bad. When the Hoss was standing for longer than 2 days, shes like exploding, when I press the startbutton. When the Engine is hot or after a brake longer than 10 minutes, the starter is yelling like a dog for some seconds until the Engine starts. Then I can smell a lot of gasoline and shes running bad for some seconds. Now I have 124 500 km on my speedometer and I want to change/repair some things.....the Carburettor is one of them. Ive done a Repairkit 2 years ago without any success. It sucks! You also have to demount the carburettor for some changes for example to regulate the float lever

A 650 cfm with mechanical secondaries will run better than a 750 on a ZZ4 stock.
Holley HP, Quick Fuel all manufacture great carbs.
The best way to go is have your carb built exactly for your engine; in the case of a ZZ4, the jets and secondaries, power valves all sized for 385 hp, 1150 lbs, 2000 stall converter. Your bike will scream.
Order your carb built to those specs.
Rick