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Exhaust Pop on decel too lean or to rich?


CBRXXRAGE

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The lean guys have it right. I built and tuned a CB1100F for a good while...even addaed an Autometer air fuel meter by welding a bung on the header collector with a heated Bosch O2 sensor. Turning out the oilot screws a little at a time until decel. pop is gone. That bike ran best a little on the rich side but in general the best spot was as lean as I could get it...still rich though.

Porter

i have been looking at wideband with data logging but are about 350 to 450 with rpm imputs , how well did your setup work for you ?

do you have some info to help me with wiring the bosch and was it a wideband

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I picked up the A/F meter and Bosch sensor from O'reillys. I had then look up a sensor that was heated...it was for a Subaru...I think. There were 4 wires on the sensor. 1 hot/ 1 ground and 2 go to the meter.

No, it was not a wide band meter or sensor.

It helped me to confirm my carb settings and was neat to see what was happening while riding...the meter only gives overall readings, but you can diagnose the overall carb circuits of pilot screws,jets/ midrange,neddles and top end, main jet sizes.

The meter responded immeadiatley to throttle changes while riding.

I left this setup as permanent...not just for tuning.

I did a search for air/fuel meters and printed out a lot of good info and even broke down the led segments on the gauge to corespond to the actual air/ fuel ratio....best power for that bike was in the 12.9 to 13 to one range at wide open throttle...I set the needles as low as I could without the bike running rough to get the best cruising mileage...that was in the 13.5 to 1 range.I tried leaner but you could hear it and feel that the bike did not like it.

I'm glad that wideband was not available at the time I did mine or I'd probably still be tinkering with it :lol:

Porter

The lean guys have it right. I built and tuned a CB1100F for a good while...even addaed an Autometer air fuel meter by welding a bung on the header collector with a heated Bosch O2 sensor. Turning out the oilot screws a little at a time until decel. pop is gone. That bike ran best a little on the rich side but in general the best spot was as lean as I could get it...still rich though.

Porter

i have been looking at wideband with data logging but are about 350 to 450 with rpm imputs , how well did your setup work for you ?

do you have some info to help me with wiring the bosch and was it a wideband

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I did a search for air/fuel meters and printed out a lot of good info and even broke down the led segments on the gauge to corespond to the actual air/ fuel ratio....best power for that bike was in the 12.9 to 13 to one range at wide open throttle...I set the needles as low as I could without the bike running rough to get the best cruising mileage...that was in the 13.5 to 1 range.I tried leaner but you could hear it and feel that the bike did not like it.

For the wide open throttle best power you should tune by changing main jets,once you pick up right main jet you can start messing with needles,pilot jet, screw etc.

Also when tunning for best power you should tune just for that,the best power not some mythical A/F ratio,although it will get you very close.

Real combustion process varies from theoretical model,plus it does not include role of exhaust system.When burning rich CO content increses versus CO2,therefore volume of exhaust gases increases too ( one C atom "mates" with one O instead of two atoms of oxygen), to the point that perhaps exhaust system becomes too restrictive.Lean ,hotter exhaust gas "makes" headers act like they are shorter,therfore boosting power at higher rpms,the peak power might increase.But you will never know without actual testing,and the sweet a/f ratio for the best power ( peak power? or highest torque? ) will vary from bike to bike.

Anyway,that is my typical,smartass ,geek answer. :oops: well not really :lol:

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Tomek, you are correct...wot power is set by the main jets. I did not go into that these had already been set up correctly....I was setting the midrange cruising with the needles. Thats why I refered to Factory Pros CV tuning guide. It would take a book to go into all the aspects of each circuit and the overlap of each one.

From one geek to another...rock on bro

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