Just got some ZX9R bike carbs and thinking of having a go at making a manifold for a pinto myself. Just a have few questions for anyone in the know.

1) The outlet on the carbs are about 40.5mm and I think the standard inlet ports on the head are about 38mm. So should the manifold tubing be tapered? Are commercial manifolds tapered or is there a step where the wider tubing meets the head?

2) I have an injection head, so should the manifold match the egg shaped inlets or is it not important?

3) I notice that the commercial ones are welded at angled rather than having the tubes bent. Doesn't this harm flow? Am I better maybe using straight tube and spacing the carbs.

4) More of an academic question now I have the carbs, but what's the point in having carbs any bigger than 38mm if the inlet is 38mm? Doesn't that make the inlet the weakest link in the chain so the speak?

5) Am I worrying about air flow too much?

Cheers!

Matching manifold to head helps the rest is academic
If it were me I would grind out the head to match the manifold, easier than tapering the tubes
Only grind a few mm in as Pinto ports are to big as standard
Don't worry about the injection cutaway

The alternative to a fabricated manifold is to respace the carbs and bolt Zx9 inlet rubbers straight up to a manifold plate.

Like this

manifold


Stu

Cheers fellas, I'm still trying to decide if I should space them or not. Which is generally considered easier? And are there any step by step guides on re-spacing these particular carbs?

Found the answer by searching

http://www.locostbuilders.co.uk/viewthread.php?tid=117413

[Edited on 10/3/13 by Skirrow]