Today was major surgery day for my Wee. Among the items on the agenda, was the air filter which has never been checked/cleaned, so the tank had to come off. It made sense to try a TBS (Throttle Body Sync) as well. I thought I'd share some things I didn't know before I started. I hope they help someone out.
I built my manometer using ATF and clear vacuum tube. See http://tinyurl.com/22masc
(VSRI FAQ) for more info.
Tip #1. A lot people have said it is difficiult to get the vacuum hoses onto the throttle bodies. I didn't find this to be the case with the tank off. The front vacuum nipple easily accessed from the right side of the bike. The rear is bit trickier but I was able to reach over from the right side and get my hand in to guide the hose on. I used 3/16" ID hose. I think it might be a hair too big. It went on way too easily. Cut two 12" lenghts of hose and put barbed couplers on the end. You can leave these attached so you can do a TBS any time. Use, the factory caps to cap the barbs when you're done. The tip is to not skip the tank removal step to install your hoses the first time.
Tip #2. You must let the engine warm up. Really warm up. I hooked my manometer up to the cold engine and it immediately started such the ATF into the front TB. I shut it down before it got there. That scared me. So, I re-read the instructions and it said to warm the engine. However, even after 3 bars appeared it still hoovered the ATF into the front TB (very fast I might add). "Hmmm it must be really out of whack", I thought. So, I turned the screw half a turn clockwise (lucky guess). It was marked with white paint, so I knew I could get back to where I started. This time it sucked in at front much more slowly. I gave it another half turn, then a full turn until it finally settled down 2 and half turns later.
However, as the engine really warmed up, it began to bias back towards the rear TB. Eventually I ended back to very close to the factory setting. So, let the engine warm up.
Tip #3. Tightening the screw (clockwise) biases towards the rear TB, i.e. it will make the ATF level lower on the front TB and higher on the rear.
Tip #4. For me, raising the RPMS with the throttle ever so slightly would bias towards the rear, while blipping the throttle would bias towards the front. You can use this to play with the current setting to make sure the levels return to even.
Tip #5. Mark your manometer for front and rear and hook up accordingly. Also mark what happens when you tighten the screw. You might not remember next time.
Tip #6. There really isn't much room under the tank to adjust the screw. Make sure you get a really short stubby screwdriver (note to Suzuki - how about a screw that could be adjusted with an Allen key?).
Tip #7. The rear cylinder gets really hot. Don't touch it.
Tip #8. Once you get close, very small movements of the screw can have great effect on the balance.
Tip #9. "The perfect is the enemy of the good". I spent two hours futzing with it. Even when you think it's dead on, a couple of throttle blips will cause one side to end up slightly higher. Blip again and it might reverse or get worse. The idle speed affects the balance as well. Give the levels time to settle before making the next adjustment.
Good luck and I hope this helps.