Jetting Helper

I am bring this one up again in hopes it will help, some of the newer people.

You can also stick a sewing pin with a large head into the rubber grip flange.

As much as I like the idea of what this accomplishes... (throttle positioning) during tuning, yup get it no doubt... Nice method while initial carb tuning....

Downfall is you'd have to leave all this on your KZ :ohmy: and hopefully have it with you on a ride later on.... Especially when changing elevations/weather conditions on a ride....

???? Recording your rpm when poo-poo occurs, wouldn't this accomplish pretty much the same...

Example idle @ 1000rpm, WOT at 9000rpm.... 4500rpm is 1/2 throttle under loaded conditions....

Or do I have this all wrong....:blush: :laugh:

Old Man Rock wrote:

As much as I like the idea of what this accomplishes... (throttle positioning) during tuning, yup get it no doubt... Nice method while initial carb tuning....

Downfall is you'd have to leave all this on your KZ :ohmy: and hopefully have it with you on a ride later on.... Especially when changing elevations/weather conditions on a ride....

???? Recording your rpm when poo-poo occurs, wouldn't this accomplish pretty much the same...

Example idle @ 1000rpm, WOT at 9000rpm.... 4500rpm is 1/2 throttle under loaded conditions....

Or do I have this all wrong....:blush: :laugh:

NAPA Store....yellow paint stick. One dot on grip flange, 3 dots on the kill switch housing at 1/4, 1/2, 3/4 throttle positions.

Simple & neat

From Sudco Mikuni Tuning Manual 4th Edition

Good Fortune!

[Click on image to enlarge view.]

From Sudco Mikuni Tuning Manual 4th Edition

Good Fortune!

[Click on image to enlarge view.]

From Sudco Mikuni Tuning Manual 4th Edition

Good Fortune!

[Click on image to enlarge view.]

Old Man Rock wrote:

As much as I like the idea of what this accomplishes... (throttle positioning) during tuning, yup get it no doubt... Nice method while initial carb tuning....

Downfall is you'd have to leave all this on your KZ :ohmy: and hopefully have it with you on a ride later on.... Especially when changing elevations/weather conditions on a ride....

???? Recording your rpm when poo-poo occurs, wouldn't this accomplish pretty much the same...

Example idle @ 1000rpm, WOT at 9000rpm.... 4500rpm is 1/2 throttle under loaded conditions....

Or do I have this all wrong....:blush: :laugh:

You, my friend, need a wideband o2 sensor. I think you'd love it. I learned more from having that setup than all of the years of reading and tinkering.

With slide carbs (not those whack job CV's ), generally speaking, at any given throttle position held steady, the RPMs will determine the AFR. Higher RPMs, higher AFR (meaning leaner). The result of this is that under steady throttle, if you suddenly start to go uphill, the RPMs go down and the AFR goes richer.

It's really the RPM that matters, though, because for the most part, whether loaded or not, the engine breathes the same at any given RPM. The load may determine the RPM, but the RPM will determine the AFR (at a steady held throttle position).

For every steady throttle position, you could actually make a jetting map of AFR versus RPM. In order to do this, you need to know the actual throttle position. And it has to be pretty precise. Like I said, even a 1/16 (or smaller) change in throttle is easily noticable on the o2 sensor when you are below 3/8ths or so. That's the area where many factors affect the jetting... pilot, main, needle, and even mixture screw on the lower end. Above 1/4, you really only need 3/8, 1/2, 3/4, full.

Another issue, is throttle position to slide position ratio. That is not a straight line relationship. Luckily, I think most manufacturers try to make it as linear as possible, though, so we can somewhat ignore this. But it does make a difference if you are studying main needle profiles where there is more than a simple taper.

"You, my friend, need a wideband o2 sensor."....

Well if you'll recall, have one... I ran in mid pipe during runs. Mid pipe runs informed me 13.8 to 14.1 range at mid range where I desired my true power band range to be...

Once figured out.... Finally ended up with a tail pipe revision of it for emission pre- testings....

As for the rest, I've learned thanks to Larry, Plum, Tim and several key members here with vast carb experiences and knowledge etc... on what to pay attention to during rides... Variables such as temperature, elevations, how I'm riding her cruise vs hard, humidity etc....

While riding, paying attention to detail on the following... Is she stuttering/missing at held rpm/speeds, is she popping on decelerations, is she falling flat on her face, is she hesitating when I pull the trigger (throttle) does she pull like a raped ape on steroids... :blink: :laugh:

I guess I'm still old school enough where learn what she likes and dislikes, learn where she runs on the $$$ and be smart/aware enough to recognize when she's not spot on....

:blush: D'oh

Forgot you had that.

Have you made any measurements while riding it with the mid-pipe arrangement? I tried taking data while the bike was parked, but just could not get anything other than idle that way.

While riding it and watching the AFR needle is where I finally saw the affects of rolling the throttle etc. But it took a lot of riding to get a grasp of what was happening. The AFR can swing wildly in normal stop-go riding. But it starts to make sense after a while.

On the side, I didn't realize AZ did emission testing for such older bikes. Very interesting. Congrats on the "pass".

Old Man Rock wrote:

"You, my friend, need a wideband o2 sensor."....

Well if you'll recall, have one... I ran in mid pipe during runs. Mid pipe runs informed me 13.8 to 14.1 range at mid range where I desired my true power band range to be...

Once figured out.... Finally ended up with a tail pipe revision of it for emission pre- testings....

As for the rest, I've learned thanks to Larry, Plum, Tim and several key members here with vast carb experiences and knowledge etc... on what to pay attention to during rides... Variables such as temperature, elevations, how I'm riding her cruise vs hard, humidity etc....

While riding, paying attention to detail on the following... Is she stuttering/missing at held rpm/speeds, is she popping on decelerations, is she falling flat on her face, is she hesitating when I pull the trigger (throttle) does she pull like a raped ape on steroids... :blink: :laugh:

I guess I'm still old school enough where learn what she likes and dislikes, learn where she runs on the $$$ and be smart/aware enough to recognize when she's not spot on....

:ohmy: We're way beyond masking tape and magic markers now... I LIKE IT

At work, I've been designing circuits using Micro-controllers in hardware and software designs in sensor A/D inputs....

This would be perfect for the Wide Band Sensor feedback (voltages) Thus conversion into Stoich values....