MartytheMartian
Legendary Knight
Yep, contrary to a lot of people's belief the idle hoses aren't necessary in order for the bike to run or even idle at roughly the right or at least at an acceptable rpm but not having the Idle valve in the system does mean that you essentially have an air leak to the cylinders after the throttle bodies so the ECU will be pumping more fuel than necessary into the engine as the Lambda sensor (if it's working) will be telling the ECU that the motor is running leaner than it should be. The main sign that the hoses are duffed is that, if you whack the throttle open and then drop it you should get some very loud bangs and pops out of your zorsts and, in the dark that will include blue and orange flames from your end can. I believe that the ECU should compensate to the extent that it prevents the motor from actually running too lean but high fuel consumption will result. I gather that, by the time the 1050 motor appeared Triumph had replaced the IACV stepper with a solenoid actuator that simply adjusts the stop on the throttle bodies rather than having a by-pass in the system. A much better idea than these damn stepper motors.