82 GPZ750 - What Mixture Screw Setting?

I've looked through my factory manual, and can't how many turns out the mixture screws should be on my stock U.S. bike. Some people recommend 1.25 turns, some like 1.5 turns, and others say 2 turns. Does anyone know what the mixture screws should start at?

Juan1 wrote: I've looked through my factory manual, and can't how many turns out the mixture screws should be on my stock U.S. bike. Some people recommend 1.25 turns, some like 1.5 turns, and others say 2 turns. Does anyone know what the mixture screws should start at?

kz.bike-night.com/
Scroll down below the pics to The Bible (aka the shop manual) link.

Regardless, it is just a starting position to get in the ball park for subsequent finer tuning of the idle and pilot circuit.

The optimum setting will be determined by actual tuning while the engine is running, and when the best pilot circuit performance is achieved, all the pilot screws will likely have slightly different settings with none of them matching.

Good Fortune!

The manual only says to record the mixture screw setting, and put it back to that after cleaning everything.

I set the screws to 1.5 turns while they were off the bike. Once they were remounted, the bike seemed to like 2 turns across the board best.

Juan1 wrote: The manual only says to record the mixture screw setting, and put it back to that after cleaning everything.

I set the screws to 1.5 turns while they were off the bike. Once they were remounted, the bike seemed to like 2 turns across the board best.

You pilot jets and your air screws work together. I think of the air screws as a method to fine tune the pilot jets. If you have correct pilot jets selected, you should end up with your air screws providing good idling and "off idle" throttle response anywhere from 1 to 2 turns CCW from fully seated. If you need to adjust your screws outside these parameters to maintain a clean consistent idle then you need to swap your pilot jets respectively.

And always use the lean-drop method of setting the screws.

Obtain highest idle, then turn the screws lean until the idle just starts to drop, then turn back to where idle comes back up a little.

To do it properly, you really need an external tach designed for this type of precision. The dashboard tach is never really precise enough.

By the way, setting the screws are the last step in a long line of steps. If you skip earlier steps, you may be wasting your time.

Engine mechanical adjustments. Then ignition adjustments. Then jetting. Then carb syncing. then mixture screws. (And everything must be clean.)

1 and 3/4 turns mate

Depends if its all stock or not. Mine has has an RC 4-1 pipe on it since it was new. I set mine around 3 out. Once you get to 4 out you need to change pilots, not before then in my opinion. Its not listed because they are plugged from the factory and they dont want you messing with them, an EPA thing

Sorry to revive such an old thread, but does anyone have a recommendation for an external tachometer as described above?

It´s like an ignition impulse counter per second,(frequency), but why you need this kind of precision???
A air/fuel mix Lambda probe would be better.

To set the idle mixture screws using the old school lean-drop method, you need a very precise tach. You won't hear the differences you need to find.
I still use this method if I think one carb is acting different from the others. With an EGA or wideband using only one sensor, you can't know if you have all of them set right or some are lean and some are rich or some random combination. You can only assume they are all the same, unless they are so far off they affect the plug color, but that's pretty far off.

I use the Actron CP7605. It's a very old one, but works beautifully. They are getting to be very difficult to get nowadays.

Most novices don't know how to use it. They don't realize you have to convert some things like crank degrees to distributor degrees and have to compensate for waste-spark etc.

www.amazon.com/Actron-CP7605-Tachometer-...alyzer/dp/B00062YUUS

Heh. I think I may actually have one of those laying around. I think my father used it back when setting points dwell was a common procedure.

I use a Colortune to set my screws.
If you must have an external tach you can get one on eBay for a few bucks. They are battery powered and function with a wire wrapped around a spark plug lead.