Hi screw adjustment and RPM

[cmarch]

I have a '96 GSX with R&D FA

Right now, my plugs are pretty wet and oily,
and I'm running about 6780 rpm.

I have a 2.0 N&S and bigger jets in it (I have the actual sizes written down at home, just can't remember them right now)

I plan on doing some hi end tuning tonite, and am curious as to what to expect. Right now I am pretty sure that I am 2 turns out on the high screws (I'll double check before I start).
After I do my initial checks, I will turn the high
screw in 1/8 turn. What rpm increase should I see?
Since the plugs are real black, an I go a half turn in, would kind of RPM increase should I see?
Thanks!

[Technical Support]

Never go in 1/2 turn spteps, that can completely overshoot your proper range! Go in 1/8th steps until you are there. Thee is no magic number, your RPM will come up when you are close.

[cmarch]

Okay, I'll do 1/8 at a time, but like how
much rpm should it increase with an 1/8 turn.

I would think that:
with the first 1/8 adjust, if there is no increase in rpm and the plugs are still black and oily, I should go in another 1/8, right?

Further more, I should repeat that process until I see the rpm increase and brown on the plugs. But when the rpm start to increase, how much of an increase is normal ?
20 rpm, 50 rpm, 100rpm ?

Thanks!

[Technical Support]

Like I said, theres no magic number - there are other factors - get your plugs dialed in, see what RPM you are at and go from there - you don't tune by how much RPM you increased!

[Bill O'Neal]

Bigger jets, bigger needles and seats and two turns out? Yep, you are rich allright. Probably needs to be out about a quarter turn or so.

[cmarch]

Thanks!

The highs were at one turn out, not two. (my typo).
I went to 3/4 and got to 6840 rpm.
At half turn, it was 6850 rpm.
At 1/4 turn out, still max 6850.

(stock prop is on it)

Any idea why a 1/4 turn in would not increase rpm?
The plugs are very slowly getting color,
how long it normally take to get the plugs brown?

Thanks guys

[Technical Support]

It takes at least a minute of constand running in range to get good color.

When you sto pseeing gains, you are close - it doesn't keep going up indefinitely.

[cmarch]

Does that mean color on the porcelin?
The electrode was brown, and the rim
of the plugs looked like your sample pics in the tuning section.
The porcelin was just a very light tan color after about 10 minutes of WOT.
The rpms were almost dead steady, just
going 6840-6850. That right?

[Technical Support]

I would say go another 1/8th turn out, light tan is not where you want to be, you want chocolate brown.

[Bill O'Neal]

Tech Support is right about going back to 1/2 out, but not because the tan color is bad. Any tan color is good. The reason to back them out a bit is you may find yourself riding on a day that has great air quality, and it might run too lean. Anytime you stop seeing a gain in rpm, quit turning them in, and back off a little. Or you will be buying pistons.

[cmarch]

Thanks... you guys are great!

I was figuring that I should do that, to be safe and all. Since I was just testing at 1/4 turn points, I was thinking that I ought to try adjustments between 1/2 and 3/4 and see where the acceleration feels best.

BTW, I was doing the adjustments on a cooler, humid day, so I figure it will run a little richer when the weather is hotter and dryer, right?

Thanks again!

[Bill O'Neal]

Typically, yes. But I have been totally fooled by the weather. The only way I know for sure is by monitoring my weather guages......