Question for you single carb guys

[marz831]

Haven't received it yet. Here's a pic the seller sent me.

 

[WaveDemon]

can I take a good look at it before you put it on your ski?

 

[marz831]

Sure. Maybe we meet up at Tom's? I will be there sometime next week to get a pump from him and have him help me tap it for dual cooling.

 

[marz831]

Ok, just got the Riva manifold in. Here are pictures of the PJS and the Riva. The PJS does not have a "lip" in the center. That is really the only difference I can see. Which should I run?

 

[sjetrider]

On dual 38mm carbs you really only get 38mm per cylender. With a single 48mm carb you get 48mm per cylender and the carb works twice as much CORRECT?????

 

[Matt_E]

Correct.

 

[motorhead10]

the lip would accelerate the air...

or if u decide that u dont like the lip you could later grind it smooth

...and sell me the one u dont want

 

[marz831]

It seems to me the the best option is the ATP mani. I have also read good things about the BCW. Is the BCW similar in design to my PJS (without the lip) or is it more like the Riva just with larger runners? The PJS seems like it would flow more volume of air, but maybe with less velocity.

...and sell me the one u dont want

You have dibs on the one I don't use.

 

[Matt_E]

The air velocity through the manifold will be determined by how much volume the cylinder & cases need. Smaller manifold = more velocity, bigger manifold = less velocity.

I think it's of little value to point at that lip and say it will be faster.

 

[marz831]

The air velocity through the manifold will be determined by how much volume the cylinder & cases need. Smaller manifold = more velocity, bigger manifold = less velocity.

I think it's of little value to point at that lip and say it will be faster.

Makes sense. I have heard that the Riva manifolds can create a lean condition at WOT. Wouldn't a bigger manifold richen up the mixture a bit and avoid this potential lean condition.........or I am overthinking this way too much?

 

[Matt_E]

You're over-thinking. The manifold will flow whatever it can flow. If there's a lean condition, it's in the carb. If it's lean in the manifold, it's lean in the carb.

 

[WaveDemon]

Sure. Maybe we meet up at Tom's? I will be there sometime next week to get a pump from him and have him help me tap it for dual cooling.

sounds good!

 

[WaveDemon]

You're over-thinking. The manifold will flow whatever it can flow. If there's a lean condition, it's in the carb. If it's lean in the manifold, it's lean in the carb.

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