Going from memory... the way its done by Triumph is to hook up the scanner and it reads the map sensor for each throttle body, you basically get a voltage reading.
What you could do at home is go out and ride your bike to get it warm, once back in the garage hook your voltmeter up to the map sensor. I do believe one wire is a 5 volt feed and the other is the output you want. Pinch off the hoses to cylinders two and three and the volt reading would be for cylinder one. Do this for cylinders two and three. The voltage should be pretty close to being the same. (The bike has to be running during these tests). If you have one that is way out of wack it could misadjusted or possibly the throttle body has a vacuum leak or the hose is damaged or leaking.
I had mine tested by Don at Baxter's and it was almost perfectly spot on, we didn't even mess with it.
Now that I typed all of that... whats the problem that you want to check your sync??
