lads

i have fitted zzr1100 carbs to my 1600 pinto engined indy,it starts,ticks over and revs up great.
my question is what jet sizes am i roughly
looking for to get it to drive cleanly.
with the standard jets in(144) the car seems to lean out over 4000 and splutters.
i drilled out a set to 190 and now it will
not rev over 3000.would i be better with something like 160?
i dont expect to get it perfect but i would like to enjoy the run down to bogg's
thank's in advance

Andy.

1.6 is about right for a 2l pinto

Your symptoms sound exactly like mine - I'd drilled my jets out to 1.6mm, got bad misfire so tried 1.65mm, symptoms even worse!

When I used an AFR meter I found out that I was seriously over-rich at wide-open throttle. My main jets are now 1.3mm (after some experimentation)! This is for a 1660cc x-flow with Honda CBR600 carbs.

Before the problem was sorted, I'd had a look at the plugs - they were very black and sooty. Now they're nicely light brown after a fast run. Might be worth whipping one out after a run to see how they look.

HTH,
David

on my 1600 CVH with ZX6 38mm carbs i fitted initially 165's but they were to rich, with use of Lambda and air/fuel monitor went down to 150's main jets, needle on position 2 of 5 and air screws two turns out and now pulls a treat

I've got a pinto 1.6 and my jets are 1.7 at the moment and seems ok, have gone throught the range from 1.3 upto the 1.7 in .5 steps to where I am now, when I get my jaw it may need to go upto 1.75 but didn't want to drill them before being able to check the afr first.

pinto 1.6, hornet 600 carbs

With yours I would start at 1.5 and then .5 in steps

Cheers

Rich

[Edited on 13/9/08 by RichardK]

Thanks for the advice gentlemen,

the car runs a bit lean on 1.44's so i will
start at at 1.50 and see how it goes.
i will also whip a plug out and see
what colour it is.i will keep you all
informed of the developments.

Andy

Might be worth getting a set of micro drill bits and gradually opening up a set of small jets.

Not sure what the step sizes are of these sets but must be cheaper than buying loads of jets.

a set like these

1.9 is far too large.. take it down to Bogg Brothers for correct set up.. all engines and carb set ups will be different due to ignition, exhausts, inlets etc... Dave B will set them up superb. Well worth the drive down there.

If you have access to a place you can run wide open about 1/4 mile, then shut off ignition and put trans in neutral, stop the car, pull a plug and look for light beige colour at the base of the ceramic insulator, correct mixture, black and sooty, too rich, white, too lean. With multiple carbs best to check all plugs. Most race cars still using carbs rely on this system at the track.