SUZUKI GSX-R1100 L
The Suzuki apprentices finally finish the beast!
Back in 2014, CMM was approached by the Suzuki Apprentice Centre in Doncaster: could we cover their restoration of a 1990 GSX-R1100L?
We like backing youth here, so of course we could! It would end up being road tested in this very magazine too. The strip-down and restoration of this legendary machine would teach the youngsters all about sorting out ‘old’ rather than ‘new’ bikes. The original plan was that the finished bike would be auctioned off for charity at the 2015 Motorcycle Live event at the NEC but things slowed down and the almost-completed machine was finally seen at the 2016 Motorcycle Live event. We hope to road test it when the warmer weather returns. So what was the 1990 GSX-R1100L? You’ll see our road test of the later, water-cooled machine but many purists feel the air-oil-cooled versions are the daddy. The 1100L is an 1127cc, 143bhp, 1465mm wheelbase 219 kilo monster, the first machine (arguably) with upside-down front-forks. This machine just happens to have a touching story attached to it. Tim Davies from Suzuki GB’S Vintage Parts Programme knows the bike well, as it belonged to his brother Howard Davies before being sold to his friend Stuart Baker, who rode it until 2003 when he left it in his garden, before sadly passing away in 2013 from Marfan Syndrome. The bike was salvaged from the garden after a decade (literally) in the wilderness and with the blessing of Stuart’s wife Tracie, will be sold in aid of the Marfan Foundation when completed and after the road test. The last time we saw the apprentices they had sorted the chassis and motor, and overhauled the brakes. So what was left to do? First up, three students (Daniel Marks from Colin Appleyard, Chris Gray from Thunder Road and Scott Robb from Saltire Suzuki) had to sort out the carburettors and standard exhaust system. The Mikuni BST36SS carbs were a replacement set as the originals were very badly corroded and beyond saving and the body numbers were checked to ensure they were correct. Should you wish to know, the ID number is printed onto the
side of the carbs and should be 40C40 for a Uk-spec set of carbs. The carbs were stripped, cleaned and inspected and the size of the main and pilot jets compared to the specifications in the manual. The students found that the main jets should have been 122.5 and the pilot jets size 40; both were much larger and a little more research revealed the carbs had been fitted with a Dynojet kit at some time in the past and the jet needles required replacement as well. The jet needles should be tapered gradually all the way down but the ones the students removed from the carbs had a very pronounced step and were clearly aftermarket. The students inspected the diaphragms, checking for splits or holes and checked the floats and needle valves for wear. The carburettor bodies were cleaned and all the passageways and drillings were blown through with compressed air and carb cleaner to ensure they were clear and clean. The throttle linkages and choke plungers were also checked for wear and smooth operation, along with the throttle stop screw and pilot screw adjusters. The carbs were rebuilt, with new main and pilot jets being fitted, along with new jet needles and emulsion tubes and the jet needles were set on the third circlip groove as per the manufacturer’s specification. The float height (14.6mm) was checked and adjusted, ensuring that the float was only just touching the end of the needle valve, without compressing the spring, while measuring from the float chamber mating surface to the highest point on the float. The pilot screws were fitted and lightly seated and then screwed out two turns to give a base setting for the fuel and air mixture. The students fitted new fuel hoses and breather pipes and with the carbs rebuilt, an auxiliary fuel tank was set up to supply fuel to the carbs. This allowed the students to check and confirm the carbs were fuel tight and showed no signs of over-flowing or leaks before the carbs were fitted to the bike. Always a good thing to do! The bike had been fitted with an aftermarket four-into-one exhaust system during its previous (racing) life, but the standard twin silencers were in excellent condition and a set of second-hand downpipes completed the exhaust system. New gaskets were fitted to the cylinder head and the collector pipe joints and the whole system was lined up and mounted before beginning to tighten the bolts, starting with the exhaust header pipes, which required the oil-cooler demounting to give enough access to the Allen bolts, and then working backwards to the silencers. The silencers required a lot of effort and elbow grease to remove the layers of dirt and grime but they polished up remarkably well and showed very little evidence of being nearly 25 years old! Who says 1990s Suzukis didn’t have a good finish? The original airbox has to be partially dismantled to allow enough access to fit the carbs and this is achieved through
removing two outer clips on the airbox and pushing the inlet mounting stubs back into the airbox, once the air filter has been removed. This is slightly more involved than it sounds as the battery and battery box have to be removed to allow access to the air filter! The carbs were fitted from the left-hand side of the bike and as they were pushed into position, the students connected the throttle cable and ensured the carbs were fully located on the mounting studs and all the securing clips were facing in the right direction to allow access with a screwdriver. The throttle cable free-play was set at 2-4mm via the cable adjuster and the air filter, battery box and battery were all refitted and secured. The routing of all the fuel lines and cables was checked and the vacuum line which would operate the automatic fuel tap on the fuel tank was blanked off as an auxiliary tank was going to be used while running the engine. The students set the bike up on a paddock stand in the main doorway of the training centre and using the auxiliary fuel tank, prepared to start the bike after checking the engine oil level.
With the ignition switched on, the oil pressure warning light and neutral light were checked and a blanking plug was loosened on the cylinder head cover so that an oil feed could be confirmed. The bike started almost straight away, with plenty of oil at the top-end of the engine and once warmed up with the tick-over set, it sounded remarkably quiet for a big beast of a bike but thankfully with no oil leaks or dramas. The charging system was checked with the engine running using a multimeter across the battery and confirmed a charge rate above 13.5V at 5000 rev/min. Next it was time to check the oil pressure and this was done by Paul Belfield of A&D Motorcycles, Mitchell Betts and James Scott from 2 Wheel Centre, Mansfield, Isaac Bown from RB Racing, Rhys Hewitt from Frettons Motorcycles, Joe Skellern from Single Tracker, Jake Summers of GT Motorcycles, Paul Swinbank of H Pigney & Sons, Josh Beddis from Frasers of Gloucester and Aaron Ringrose from J&S Motorcycles. The engine had been started and run several times and a new first year group used an oil pressure gauge to test the oil pressure. With the engine warm, the students fitted the oil pressure gauge to the main oil gallery at the bottom of the engine. They confirmed the oil pressure was 50psi at 3000rpm with the oil at 60°C. This was within the tolerance given by Suzuki which is above 43psi and below 85psi. With all of the build coming to a conclusion, time was still short to get the bike ready for its debut on the Suzuki Vintage Parts Programme stand at Motorcycle Live. Several second and third year apprentices were involved in fitting the bodywork and completing the bike ready for the show at the NEC and these included Daniel Marks, Scott Robb, Paul Belfield, Mitchell Betts, James Scott, Joe Skellern, Jake Summers, Paul Swinbank, Josh Beddis and Aaron Ringrose.
The original fuel filler cap was cleaned and lubricated and after a little gentle persuasion (and a lot of WD-40) the key and lock mechanism started working smoothly again and the whole assembly was fitted back into the top of the fuel tank. With the tank laid upside-down, the students fitted a new fuel tap and after testing with a multimeter, the original fuel level sender unit was screwed back into the tank and new fuel lines and breather pipes fitted. The tank was refitted with the original mounting rubbers and the fuel tap control knob was fitted last as it will not clear the frame until the tank is in position. The students then turned their attention to the upper fairing section. All the electrical connections to the lights, switches, horn and indicators were located and checked and new bulbs were fitted in the twin headlights and side lights. The original screen was carefully fitted to the upper fairing using original Suzuki fixings which are small aluminium blind rivets and securing clips. The fairing was loosely located and the indicators and mirrors fitted before finally securing the fairing in place. The mid-section fairing panels were fitted using new clips, washers and screws and the lower panels which form the belly-pan were also lined up and secured after checking them for correct alignment. The students moved to the rear of the bike and fitted a new set of rubber grommets to the fuel tank and brackets which locate the side-panels which are rather longer than conventional panels, running from the lower part of the fuel tank all the way back to the rear light in one long section. The final section over the rear light and a new number plate were fitted, along with the pillion grab rail. The rear seat section was secured using two wing nut type bolts and the rider’s seat was fitted and the locking mechanism checked for correct operation with everything in place. Finally the front mudguard was carefully threaded into position and the front brake hoses located into the keeps, riveted onto the mudguard and with a quick polish the bike was ready for the show in all its new-found glory! Eagle-eyed readers and lovers of the big GSX-R will spot the small issue with the seat covering: it’s black and not blue. This will be sorted before any road test but this in no way mars the great job done by all the apprentices over the last couple of years.