Saturday July 26th 2025

Suzuki GSF1200 Bandit…

Graham and Don worked to tighten all the rocker cover bolts and install the oil feeds to the back of the rocker cover. It was a shame that we couldn’t install all of the shiny new rocker cover bolts because some had been modified with 6mm bolts fitted to holes drilled through the heads of the originals and screwed into helicoils. One bolt, the second left rear bolt would barely tighten so we would have to hope it stayed oil tight. Once the rocker was back in place it was time to take it outside get it warmed up and balance the carburetors. It was at this point that it through a couple of obstacles in our path. Firstly the battery fitted to the bike was flat. That was quickly overcome with another fully charged battery. However despite having a fully charged battery there was no sign of life from the starter motor. Steve soon worked his magic on the clutch lever cut out switch. This is a switch designed to prevent the bike from being started unless the clutch is pulled in.

Whether or not the pilot fuel screws had been tampered with was an unknown quantity. These screws are in a hard to reach position facing vertically downwards at the engine end of the carbs. Turning them in or out varies the amount of fuel being drawn past the edge of the throttle slides. Screwing the screw in decreases the amount of fuel and screwing it out increases it. Out of interest if the screws are located on the air filter side of the carburetor they are called pilot air screws and control the amount air being mixed with a given amount of fuel. Unlike a pilot fuel screw, turning a pilot air screw inwards richens the mixture and turning it outwards weakens the mixture by allowing more air to pass the screw.

In the case of our Bandit the two inner screws were too stiff to turn with the limited amount of room available. So Graham turned the two outer screws until the highest tickover speed was achieved. It was significantly higher than it had been indicating that the original position had been quite a bit too weak. Whether it was worth pulling the carbs back off and freeing the pilot screws in the middle carbs would depend on how the bike ran when out on the road. As it stood it was idling well enough that it didn’t appear to be justified.

Now it was time to balance the bike’s four carburetors. The bike has a spigot on each carburetor. Three of them had rubber blanking plugs whilst the remaining one had a pipe fitted to it that applied the engine’s vacuum to the vacuum operated fuel tap. Graham first attached each vacuum gauge to the spigot on number 1 cylinder and used their adjusting screw to get each gauge fluctuating by a similar amount. Then with gauges attached to all the spigots the amount of vacuum could be compared. There were small variations in the level of vacuum shown by each gauge. To overcome this Graham used a screwdriver to turn the adjusters situated between the carburetors. They were poorly located and difficult to turn but after a lot of jiggery pokery Graham managed to achieve a reasonably smooth tickover of around 1000 RPM. Only time and a long ride would tell if further tuning was needed, but for the time being it was idling nicely. Andy our paintwork ace got to work shining up the front mudguard and the fuel tank to a glossy finish almost better than new.

Whenever you are balancing Constant Velocity carburetors (Where the slides are drawn upwards by the engine's vacuum) it is worth checking how the adjusters work. In the case of our Bandit, the throttle cables attach to the second from the left carburetor. This meant that all the other throttles had to be adjusted relative to the second left carb. The left-hand carb could be adjusted easily enough but the centre right throttle must be adjusted before tackling the right-hand carb. If you tried adjusting the right-hand carb and then doing the centre right carb, it would alter the opening of the right-hand carb as well, upsetting any degree of balance you might have achieved.

GSF1200 Bandit Fuel Tank (Left)

GSF1200 Bandit Fuel Tank (Right)

Ducati 250 Single…

Using a very clever tool that Jason bought in, Jon riveted the components of the bike’s seat together and attached the seat unit to the bike. Now the bike looked complete and maybe even ready to try out on a racetrack!

Almost ready to go racing?

Member’s bikes…

Honda Vigor 650…

Mal worked install a new chain and sprocket set on the bike. With both sprockets fitted and the chain ready to go on, he was frustrated by a spacer that had apparently gone missing since the rear wheel had been removed. AJ stepped into the breach and offered to turn up a replacement spacer, so all was not lost.

Good progress made today but a missing spacer frustrates things.

KTM 990…

Committee member Jo spent a little removing the bash plate from her bike to hunt down an oil leak that was leaving a small pool of oil on the ground whenever the bike was parked up. On inspection it transpired that the leak was coming from around the cap retaining one of the bike’s oil filters, so a new O-ring would be the order of the day.

Oil leak located!

Kawasaki ER6...

Work was done to replace the front fork seals on a member's Kawasaki ER6. However once the forks had been stripped apart it was found that the replacement that had been bought in with the bike were just a fraction too large for they stanchions they needed to be fitted in and the bike would have to remain the workshop until correctly sized replacements could be purchased.

Wrong sized oil seals how frustrating.

In other news…

Ian Gravell and Seimon Pugh-Jones visited the club as part of Ian’s very kind offer of helping the club to produce promotional material. Ian interviewed some of us whilst Seimon used his film making talents to begin capturing material to include in the video. Seimon in particular was especially surprised by the extent of the activities going on at the session. Ian thought it great that part of a former place of worship was being used to give members the support that being part of a common interest group gave. They left indicating that they would return in a few week’s time to do some more in depth work.

The weed’s took a battering. Phil Howell’s had bought in his spade. Pete and others set about clearing the weeds that were growing at the base of the chapel and vestry walls. After their efforts the whole place looked a good deal tidier.

Weeds dealth with - looking much tidier.

Finally, special thanks go to those involved adding a raised back to the work bench situated on the stage area. It would eliminate the risk of anyone working at floor level in front of the bench, being hit by anything from work being done on the bench.

All together - much safer.