JoePap
Registered user
I've recently fitted a wideband O2 gauge with a sensor that I can swap between the two downpipes. It gives a digital reading with 14.3 being perfect combustion. Low numbers are rich, high numbers are lean.
Overall the bike is running pretty well. The only issues are
1) Running rich on tickover - reading around 10 or slightly under on the Air Fuel gauge.
2) Tickover seems a bit high (Just under 1000 rpm)
The mileage is 35,000. Being an early bike it has the very simple fuel injection system with no lambda sensor.
I've done all the service items including
- Recent injector clean
- Valve clearances
- There's a little slack in the throttle cable so it's not opening the throttle bodies when the twist grip is shut off
- The "Choke" cable is working properly and not binding or part opening
- The throttle bodies are balanced
- To get the tickover down below 1000 rpm I've had to screw both big brass air screws fully home (See further comments below)
- Throttle position sensor set to give zero volts on the number 1 connector with closed throttle (To achieve this I had to rotate it anti-clockwise almost to the limit)
- Ive tried adjusting the C0 potentiometer. Measuring at the number 2 (middle) contact. I can vary the voltage from 0v to 4v with no noticeable affect. The bike was fully warmed up when I did this.
- As recommended by the manual and various info online, I've left the throttle stop screws alone
When cruising and on wide throttle openings, the bike pulls and rides very well. There's no surging. The air fuel gauge tells me the mixture is very good.
But when I leave the bike ticking over, the bike labours a bit. It smells and sounds like it's rich and the air fuel gauge confirms - reading around 10. Although tickover is nearly 1000 rpm it sometimes stalls.
If it was a carburettor bike, I’d open the air screws and adjust the throttle stops. But the instructions for the oil-heads say to leave the throttle stops well alone and to use the air screws to adjust tickover rather than idle mixture.
I'm tempted to look into re-mapping the ECU but only if everything else is adjusted properly.
I'd be interested any suggestions and any insight into the system including
- why the throttle stops should not be adjusted?
- Why the air screws are used to adjust tickover rather than idle mixture?
- How the CO potentiometer is supposed to work? Are higher voltages from it telling the ECU to add or reduce fuel?
Thanks.
Joe
Overall the bike is running pretty well. The only issues are
1) Running rich on tickover - reading around 10 or slightly under on the Air Fuel gauge.
2) Tickover seems a bit high (Just under 1000 rpm)
The mileage is 35,000. Being an early bike it has the very simple fuel injection system with no lambda sensor.
I've done all the service items including
- Recent injector clean
- Valve clearances
- There's a little slack in the throttle cable so it's not opening the throttle bodies when the twist grip is shut off
- The "Choke" cable is working properly and not binding or part opening
- The throttle bodies are balanced
- To get the tickover down below 1000 rpm I've had to screw both big brass air screws fully home (See further comments below)
- Throttle position sensor set to give zero volts on the number 1 connector with closed throttle (To achieve this I had to rotate it anti-clockwise almost to the limit)
- Ive tried adjusting the C0 potentiometer. Measuring at the number 2 (middle) contact. I can vary the voltage from 0v to 4v with no noticeable affect. The bike was fully warmed up when I did this.
- As recommended by the manual and various info online, I've left the throttle stop screws alone
When cruising and on wide throttle openings, the bike pulls and rides very well. There's no surging. The air fuel gauge tells me the mixture is very good.
But when I leave the bike ticking over, the bike labours a bit. It smells and sounds like it's rich and the air fuel gauge confirms - reading around 10. Although tickover is nearly 1000 rpm it sometimes stalls.
If it was a carburettor bike, I’d open the air screws and adjust the throttle stops. But the instructions for the oil-heads say to leave the throttle stops well alone and to use the air screws to adjust tickover rather than idle mixture.
I'm tempted to look into re-mapping the ECU but only if everything else is adjusted properly.
I'd be interested any suggestions and any insight into the system including
- why the throttle stops should not be adjusted?
- Why the air screws are used to adjust tickover rather than idle mixture?
- How the CO potentiometer is supposed to work? Are higher voltages from it telling the ECU to add or reduce fuel?
Thanks.
Joe