If out of balance adjust the brass air bypass screws. Then check the balance at just off idle. Set the bypass screws to the specs first.
There are stop screws under the TB if this needs adjustment. Disconnect the linkage from left to right for this step on 4 valves. After the synch is as good as you can get it, you can see if the base position of the throttle plates is close at idle. Dont worry about what it does at idle right now. This is where the engine moving some air. The most important part of the synch is to do it at 3000 rpm. Most models its done with a plastic thumbwheel under the left side TB. The TB must be adjusted to a very fine degree of balance. Ignore the fact that it runs worse than it did. Connect your balance meter/carb sticks and start bike. Turn them in counting the turns until closed. There are brass bypass screws on the TBs. Access to an exhaust gas analyzer is a boon. I have used mercury sticks, but really have been impressed with the convenience and precision of the Twin Max electronic balancer. To start the setup you will need a very accurate way to balance the throttle butterflies. These are much more sensitive than carbed bikes. So lets make the most of what we have to work with.Īny maladjustments can turn a great running bike into a sputtering pig.
A real air mass meter with oxygen sensor closed loop control would make for a bike that runs perfect.Not likely to happen. Its a calculated model at some elevation. Mainly because of cost or space limitations, there have been no provisions for measuring the actual induced air. These systems have had problems on bikes ,and not just Guzzis. It is much more under heavy acceleration. This is the pulsewidth.It’s measured in milliseconds. The amount of fuel is governed by the time the injector is turned on or open. It decides in an instant how much fuel to inject on the next cycle. So the ECU knows speed, load and temperature of air and engine. It counts the teeth so the ECU knows where the pistons are in their stroke and the engine speed. The camshaft position sensor is an inductive type. The signal from ECU to these sensors is known as reference voltage. The throttle position sensor works in a similar way. It sends a low current voltage signal to these temp sensors where it is grounded to a varying amount based on the temp. The electronic control unit (ECU) is the brains of the outfit. As they heat up the resistance goes down. These are NTC, negative temperature coefficient. It uses air and cylinder head temperature sensors. I went back and had him do a smoke test and he said he didn’t find anything, although idk if I trust him.įrom my understanding a high negative fuel trim is from too much fuel.The following is Mike Haven’s article from the MGNOC Newsletter on Injection Set-Up for all Guzzis But only in gear and I only hear it in 1st-3rd gear at exactly 2500rpm and 3000rpm there is a high pitch sort of whistle sound, like a hybrid between a kazoo and a whistle. I had a shop put on Crawford billet Blocks and a ace 250 header/op. I reflashed my tune and car drives better but LTFT is slowly creeping back up as well as STFT being around 15%.Īnother issue possibly causing this just never noticed fuel trims from lack of driving and lots of reflashes. Recently I noticed my car was bogging down and bucking at low throttle, low rpm so I started looking st my fuel trims and at idle, low rpm, low throttle my STFT and LTFT where both around negative 15% (30%), at Highway cruising as well as WOT they are both around 0.