Main jet question

[Gusable]

So my 94 cali 1100 is running really good and I’m very happy with it. (Phf36’s) That being said the tune right now is 60 pilot, AB268 atomizer, K5 needle on second notch and 145 main jet. That 145 is what was in it when I got it. From what I know it should have come with a 130 main stock.  If my math is right the 145 is only about 11% more fuel.  The fuel mileage is what I’m trying to improve. It’s about 30.5-34.5mpg at this time with 7/33 axle. Accelerator pump tuning is something I’d like to do as well.  So that main jet is in play at 4000rpm yes? I think that’s about 1/2 throttle.  Thank you

[Gusable]

The chart

[guzzisteve]

Mark the switch w/tape every 1/4 throttle, then on bottom 1/8 throttle. Put tape on grip to correspond with marks on switch.
Amazing, you'll see you will be at 1/8 throttle in high gear NOT half. This at a steady throttle once at 4Krpm.
You won't know unless you mark the throttle, you'll only assume you are correct

[moto]

The previous two posts have it right, I believe. But a minor correction on your calculation of the difference in flow between a 145 and a 130 main jet. The flow varies with the area instead of the diameter of the opening, so the ratio is 145 squared over 130 squared, which works out to a 24% increase instead of an 11% increase. (The other terms for the area of a circle cancel out between the numerator and denominator.)

[Gusable]

Thank you for that mathematical correction. That’s the real numbers I was looking for.  If I could take 20% out of that main I’d like to try that.  Thank you!

[moto]

Thank you for that mathematical correction. That’s the real numbers I was looking for.  If I could take 20% out of that main I’d like to try that.  Thank you!

You're welcome, of course. You have the jet you want in your hand so to speak. Since the flow of the 145 jet is about 24% greater than the 130 jet, it's also true that the 130 jet flows about 20% less the 145. That is, (145^2)/(130^2) ~= 1.244, while (130^2)/(145^2) ~= 0.804.

Even though the main jet doesn't have much effect at the quarter or so throttle you will be using during cruising, I would certainly recommend going back to the stock main jet as your first step. Many riders go up too far on the main jet trying to correct other perceived problems in their setups.

[moto-uno]

 Your main jet isn't of any consequence with your highway mileage concerns !
 Your idle jet (and it's adjustment screw) , throttle slide #( cut away ) and needle jet and needle position are
 all involved and over lapping at your highway speeds , and , this is also kinda important ,
 make sure your needle and needle jet are not suffering from high mileage wear .  Peter

[Gusable]

Pilot,needle and atomizer are all brand new.  I wish I could run less pilot but it just does NOT like anything but that 60. Anything less and it lean pops/stumbles.  Runs and idles great with it.  I shorted my factory long screws to .100 but have a new set of longs I can try. I think maybe the long tip will give a better signal through that circuit

[Gusable]

Major update! I got a cyber Monday deal on a quick detach phone mount and using a GPS speedo app I calculated the REAL trip miles on this bike. My speedo is dead nuts accurate. 7/33 in back, they must have done the trans gear too!  Trip meter is slow though. Said I went 27 miles really went 31 ish!!  End result is 43MPg!!! I’m so happy.  I did order a set of 130 mains. Next time I go in there I’ll install them and put the leaner AR268 atomizers in there

[Wayne Orwig]

 

[PeteS]

Main jet is set for WFO. For mid range you adjust the needle and needle jet. I tuned my 850 LeMans at the drag strip. Stock 135 main was replaced with a 143 and a result of 10mph greater top end. Ethanol fuel runs leaner. It takes X amount of horsepower to go a certain speed, not a particular throttle position. If you aren’t feeding it enough energy you just have twist the throttle further. Changing main jets is just false economy.

Pete

[Gusable]

I’m keeping the 145’s for now. 43mpg I’m thrilled!