Topic: Need some carb educating ,

[Que75cb750]

Yes there is tons of info on carb tuning etc but I can find answers I need, maybe they are to simple or obvious but carb tuning is a bit of a mystery to me and any helpful info would be greatly appreciated . I have a 75 cb750f, I have a Mac slip on and I did have pods, with the pods it ran like crap so I replaced the air box and all is good. Even though there is a lot of negative feedback with pods on these carbs  I would like to try again and play with the jetting, this is where my inexperience in carbs comes up,,, SO , I’m not sure what jets i have but assuming they are 40 , what is 2 sizes up? What increments are jets made? Also when changing main jets do the other jets need to be changed as well? Pilot , idle?? Are the pilot jets easily identified like the main jets are, numbers stamped on them?
Lots of info on base adjustments and vacuum syncing so I’m good there.

[ekpent]

 The round top carbs only have two jets, the main and slow jet.The needle running off the slides may be a little different through the different carb years and the height can be adjusted. The only other adjustment other then the float level is the air screw. There very simple in design. Maybe somebody can give you suggestions on what set up they are running as far as main jet size etc.. Stock for your carbs would have been a #105 main and should be marked.

[PeWe]

I do not know which carb your bike has.
If same as K6, pilot jets stock 40 work fine with pods and 4-1.
My K6 had pods on stock carbs in the 80's. Rather loud 4-1, 836cc, ported head, larger in valves, cam.
- Pilot 40
- Needle 4th notch from top.
- Air screws , stock is 1 +/- 1/8 turn out. Mine were 1/2 turn out.
This adjust idle to around 100-120km/h  steady cruising.
- Try 3/4 ( good idea to go for a longer ride and adjust now and then during the ride with correct screwdriver.  Increase 1/8 to see if it change to the better when engine is warm. Minimum 15 minute ride before.

Adjust 1/8 each time which is half of a quarter, easy to remember. See the screw as a clock to remember.

- Main jet is the question. It depends on how free your exhaust flows, not only the less restrictive pods.
I guess 120-135 area.
- Try 125 to start with.

Change needles really sucks on stock carbs that have to be removed and carbs loosen off the rack to remove the throttle mechanism and change needle clip. I tried without loosen them from rack, but just impossible.

Bench sync work fine if carefully done with drillbits from the Inlet side to the throttle.

[Motorcycle jones]

That was one of the great things about the original 1969-70 carbs is that you could remove the slides
without taking the carbs off of the bike. You still need to remove the gas tank.

[Bodi]

I've found that the pilot jet has to go one size smaller with pods. Can't explain it.
With stock needle taper it's unusual to get it running correctly through from idle to WOT. I had to set the needles to be OK or lean through the throttle range, then thin them down in the lean zones. Just some brasso on a rag pinched at the lean zone of a needle in a drill.