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Discussion Starter #1
Those of y'all running larger carbs, where did you get the manifolds to fit them? I'm trying to put a set of 30mm carbs on a CB450, but need new manifolds that are not only larger in diameter, but long enough to prevent the carb from hitting the cylinder head.

Anyone put larger carbs on a CB450?
 

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Seems like every application is different.
Some times you can use the OEM engine side, and the OEM carb side (from the larger carb) and splice them with hose.

Other time you can use the OEM engine side and a spigot mount carb and splice with hose.

Both require opening up the intake port/manifold to smooth flow a bit.

I usually fabricate new intakes using slightly bent tube of the right size and a some painstakingly hand made flanges.

Of course if it's a 175 I have a batch of laser cut flanges, I just place the carb, figure out how long and how much bend the tube needs and weld it up.
JohnnyB
 

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Discussion Starter #5
quote:
Yeah Robo...what kind of carbs you using?
Mikuni.. now that I think about it, they might be 32mm. But they should go well with the mildly ported motor + cam + open pipes I have.

I already have a ton of mikuni jets from the RDs, and nothing for the stock carbs.
 

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Rob, you know how to tune those freakin things?

I gave up on my set. Went to the Keihin PE race carbs... very easy to tune and well suited to a four stroke.

Don't think the PE's are avialable in the US in the right size for your application though.
JohnnyB
 

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Discussion Starter #8
quote:
Rob, you know how to tune those freakin things?

I gave up on my set. Went to the Keihin PE race carbs... very easy to tune and well suited to a four stroke.
well, I've got the RDs running pretty well. Only took me a few years of half-assed attemts and seizing to get it right.

Figured that I have the carbs already, and you can't get jets for the stock ones... There's a dyno with a CO2 analyzer in Windham, NH that I might try once I get it close. We'll see. This is all for a streetbike afterall.
 
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