SUZUKI GSF1200 BANDIT
Andy B is on it with his ‘Maid of all work’ Bandit as he tries a Stage 1 and 3 tune-up for the Suzuki: but does he make it breathe more easily?
Bolas is back with the Bandit!
Things have been rather manic of late in the Bolas household which has meant the old 1200 Bandit has been pressed into service for all sorts of jobs. What jobs? Well, everything from bike displays at shows to the odd jaunt on track days, touring Europe loaded up with luggage and even a few blasts down the quarter mile strip at Santa Pod during the Race, Rock ‘N’ Ride event, which was a great weekend! Anyway, back to the bike. As mentioned before the next step with the old Bandit was to fit a Dynojet kit to complement the full exhaust system. Having never really had a great deal to do with four-strokes other than regular servicing this bike is a bit of a learning curve for me but also shows what you can achieve if you take your time and put your mind to it. As with the basic maintenance pieces I did a few issues back, I hope it encourages people to have a go at maintaining their bikes and getting to know them a little better without getting too far out of their comfort zones! I ordered the Stage 1 and Stage 3 kit and a K&N air filter from B&J Bikes in Willenhall and it arrived in just two days, which was pretty good! I always try to use local suppliers rather than that well-known internet auction site if I can as you never know when you may need help or advice with what you have bought! I’m not sure really as to why it’s a Stage 1 and 3 kit though; do they even do a Stage 2 kit does anyone know? The Stage 1 set-up is for bikes running either a can or exhaust system and a K&N filter, while the Stage 3 kit is for bikes running those mods plus pod filters instead of the air-box: the only difference is the size of the main jets. Stage 1 has size 100 and 104 main-jets (standard main-jets are 102.5) while the Stage 3 has 150 and 155 mains! I’m happy to keep my air-box as I had a bad experience with a Mk3 Gamma running pod filters which wouldn’t run on two cylinders in the rain, so I’m not
going down that route again! Anyway once I had my goodies I managed to talk Keith Brindle from Chase Superbike Centre in Bridgetown into allowing me to use a workbench to fit the kit and also pick his brains and use his knowledge on fourstroke set up which he kindly did to help me with some base settings! So with the bike up on the ramp, I removed the petrol tank to expose the carbs (see pic 1) and rear panels to allow access to the air-box fixings (pic 2). After removing the air-box fixings, I then drained the carbs of fuel (pic 3) then released the clamps from air-box rubbers and pushed the air-box back a few mm (see pic 4) then released the clamps on the intake side to allow the removal of the carbs. With the carbs free I lifted them through the gap, having covered the frame and top of the air-box to prevent any debris etc. finding its way in to the intake and engine (see pic 5). Next we removed the float bowls from the carbs, one of which gave me a little bit of trouble getting one of the screws out and needed to be persuaded out with precision tapping (copyright Andy B, see pic 6). With the float bowls removed it was time to change the main jets (see pic 7); out with the standard jets and in with the larger of the jets in the Stage 1 kit. After fitting the new main-jets, I then refitted the float bowls and turned the carbs over so I could remove the carb tops. Once I had the tops off I could then remove the diaphragm (pic 8) and replace the springs and needles (see pic 9). New spring and needle are on the left and the original Suzuki parts to the right, then refit the tops, being careful not to lose the little O-ring which the top seats on as this can easily be lost. To start with I set the
needles as per the settings in the kit’s instructions. I then set the mixture screws to two-turns out from fully in. I then reassembled the bike fitting the new K&N air filter as well. The bike started up easily after fitting the kit but struggled to rev cleanly after 2500rpm while stationary. The only thing for it was a test ride and wow – what a test ride. It must have been the shortest ever test ride as the bike was so lean it would barely pull. Have you ever done something and instantly regretted it? Well that’s how I felt! So it was back to the drawing board. As the bike felt lean, Keith recommended refitting the standard filter to see if this would richen things up a little. I did this and went out again, the bike was instantly more responsive although not completely glitch free. I decided to do a few miles with this set-up for research purposes. That evening I got the bike in my own workshop and lifted the needles by two places to richen things up enough to enable me to refit the K&N filter. This set-up was much better and the bike is much more lively, picking the front wheel up in the lower gears and it was also a great deal more responsive throughout the rev-range especially the top-end. You can now ride the bike in top gear at 30mph and roll the throttle on and the motor responds smoothly all the way up to its redline, although I’m not sure whether to drop the needle down one notch to lean it off slightly and see if I can eliminate the slight woolly feeling I get now and again. Also this may improve the bike’s mpg as when I went to Assen on the Bandit before, it was returning a little over 30 to the gallon which I thought was a little poor. I could be wrong though, as I never really paid much attention to its economy before these mods were carried out! I’m guessing really, so I need to get it on the dyno again. Watch this space but don’t hold your breath as I have a lot of work to complete on the TL and there may also be another project in the wings so the 1200 will have to take a back seat: for now at least! On another note: I’m loving the Bridgestone BT016 Pros. They’ve performed well in all conditions, even torrential rain in Holland. Okay, so I don’t think they will have the longevity of the previous BT023S but I don’t mind that for the extra grip and feel they have given the bike. Can’t fault them!