Nikki carb jetting
 

Ok, I have run through the forum and didn't see any mentions on recommended sizes for the air bleeds and jets. I have an 84 gs body with an 85 motor (and my choice of 81gsl, 80s , or 85 carb) with no emissions, RB header, strait pipes, high flow fuel pump w/ .5 - 5.5 psi regulator from holley. I would like to ordernew air bleeds, fuel jets, and any other recommended internal crap needed for more fuel flow without going too far. I do not know the size of the stock equip so that would also help (for I have heard to jump in increments of five) but any info is apprecieated.

TIA

peace

Stock, the air bleeds aren't generally changeable. What you do is drill them out and tap them for changeable jets. The trick is finding jets that small...

The main problem with fuelling is the stock carb delivers too MUCH fuel. I used to hear 95 primary jets / 150 secondary jets but of course that's just a starting point (stock is something like 97 / 160-170) and it'll depend on what combo you have.

How can I tell what I have? Is it marked on the jet or do I need to pull out the ole micrometer?

Thanks for the info peejay.

peace

It's marked on the jet.

Find out if you need to go richer or leaner (this is where plug-reading or an O2 meter come in handy) and make small changes. It helps to have a stopwatch and a large flat area, or a dragstrip, so you can quantify what makes your engine happier. Best is a dyno, of course...

Where would one purchase or acquire these new fuel jets?

slorimer - I believe mazdatrix carries them and Paul Yaw is another.

peejay - once again thanks for the info

As for the rich/lean situation, has anyone tried the false sparkplug that changes color for optimum air/fuel ratio tuning? I think jc whitney sells them. Would they work on a rotary?

peace

well you can tell by the color of your sparkplugs some.

real helpful, jeremy...:p:

put new plugs in the car, go for a full throttle run, then shjut the car off and coast to a stop.

look at the insulator.

white = lean
black = rich

what you're GENERALLY looking for is about the first half of the insulator to be brownish. I say generally because your tune of course will differ, and also it doesn't really tell you if the car is rich down low and lean on top or vice-versa (it's usually vice-versa) but it does tell you the general state of tune.

You can get a whole range of jet sizes from Mazdatrix.

don't be dissin' my ghetto engineering, yo!

sweet gotta try that sometime, any problems stopping without vaccum to the brake booster?

peace

your brake booster should still have vacuum for 1-2 depressions of the brake pedal. Just don't pump them when you stop, hit them once and hold it...

Jeff