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Maintenance and repair Suzuki GT750-B (BS)

Installed BOLT 13, we made a test run, no gear box oil has leaked. NOTICE: Now we understand why there was only 800cc gearbox oil left in the engine after we drained the gear box oil for the maintenace.
Installed BOLT 13, we made a test run, no gear box oil has leaked. NOTICE: Now we understand why there was only 800cc gearbox oil left in the engine after we drained the gear box oil for the maintenace.
So BOLT 13 ready to install: With the aluminum washer and enough sealant to prevent gear box oil leakage again.
So BOLT 13 ready to install: With the aluminum washer and enough sealant to prevent gear box oil leakage again.
Of course first you have to clean the location for BOLT 13.
Of course first you have to clean the location for BOLT 13.
On this photo BOLT 13 wthout all the washers and other stuff and the NEEDED aluminum washer. We needed a mirror to repair this oil leakage. And yes doing maintenance in this way is very hard to do.
On this photo BOLT 13 wthout all the washers and other stuff and the NEEDED aluminum washer. We needed a mirror to repair this oil leakage. And yes doing maintenance in this way is very hard to do.
Some one really did a bad job, you can see that there are more parts installed on BOLT 13, a secure washer, a wire clamp, and a normal washer. All wrong!
Some one really did a bad job, you can see that there are more parts installed on BOLT 13, a secure washer, a wire clamp, and a normal washer. All wrong!
You can see a drop of gearbox oil hanging on BOLT 13. This just means: The former engine rebuilder did NOT read the maintenance manual and doesn't have any knowledge of the GT750 engine at all.
You can see a drop of gearbox oil hanging on BOLT 13. This just means: The former engine rebuilder did NOT read the maintenance manual and doesn't have any knowledge of the GT750 engine at all.
There where we found the gearbox oil under the engine was a WELL KNOWN place! There is a special M8 bolt in the lower engine casing: Bolt 13, this bolt needs a special treatment! Yes you have to do so!
There where we found the gearbox oil under the engine was a WELL KNOWN place! There is a special M8 bolt in the lower engine casing: Bolt 13, this bolt needs a special treatment! Yes you have to do so!
SITE UPDATE 26102025: After we made a test ride on this GT750-B we saw the engine leaked gearbox oil at the LEFT hand side of the engine. We found this oil leakage ONLY when the engine was running.
SITE UPDATE 26102025: After we made a test ride on this GT750-B we saw the engine leaked gearbox oil at the LEFT hand side of the engine. We found this oil leakage ONLY when the engine was running.
So we did a lot of work on this GT750: Re-routed wire cables and clutch cable on the left side. All the work (it was a lot of work) is done on this GT750, the GT750 can go back to the owner.
So we did a lot of work on this GT750: Re-routed wire cables and clutch cable on the left side. All the work (it was a lot of work) is done on this GT750, the GT750 can go back to the owner.
So we did a lot of work on this GT750: Re-routed wire cables and front brake hose right side.
So we did a lot of work on this GT750: Re-routed wire cables and front brake hose right side.
So we did a lot of work on this GT750: Installed a front brake switch and rerouted and replaced the front brake hoses in the right way.
So we did a lot of work on this GT750: Installed a front brake switch and rerouted and replaced the front brake hoses in the right way.
So we did a lot of work on this GT750: Installed an ACCENT elektronic ignition, replaced the bad battery connection by new wires.
So we did a lot of work on this GT750: Installed an ACCENT elektronic ignition, replaced the bad battery connection by new wires.
So we did a lot of work on this GT750: The result of rerouting wire cables, hoses and clutch cables is clear to see, all of them are routed on the right way. Important the GT750 is now safe to ride.
So we did a lot of work on this GT750: The result of rerouting wire cables, hoses and clutch cables is clear to see, all of them are routed on the right way. Important the GT750 is now safe to ride.
So we did a lot of work on this GT750: Agian the new rear tire, but also installed the licence plate properly.
So we did a lot of work on this GT750: Agian the new rear tire, but also installed the licence plate properly.
So we did a lot of work on this GT750: Installed the exhaust on the right way by using the right bolt and used washers between the exhaust mounting and the frame.
So we did a lot of work on this GT750: Installed the exhaust on the right way by using the right bolt and used washers between the exhaust mounting and the frame.
So we did a lot of work on this GT750: Cleaned the carburetors thoroughly, rebuild the carburetors and adjusted the carburetors by adjusting on a running engine and on exhaust temperature.
So we did a lot of work on this GT750: Cleaned the carburetors thoroughly, rebuild the carburetors and adjusted the carburetors by adjusting on a running engine and on exhaust temperature.
So we did a lot of work on this GT750: Cleaned the carburetors thoroughly, rebuild the carburetors and adjusted the carburetors by adjusting on a running engine and on exhaust temperature.
So we did a lot of work on this GT750: Installed a new rear tire.
So we did a lot of work on this GT750: Installed a new rear tire.
We couldn't get the wheel balanced in a proper way, conclusion BAD wheel bearings so we needed to replace the bearings to.
We couldn't get the wheel balanced in a proper way, conclusion BAD wheel bearings so we needed to replace the bearings to.
The seal at the rear wheel is totaly worn. When you installe refurbished parts you need to sand it untill the surfaces are shining.
The seal at the rear wheel is totaly worn. When you installe refurbished parts you need to sand it untill the surfaces are shining.
The other side of the GT750, notice the license plate, some installed the license plate with 5 mm difference on left and right side. As i am a technician i can not handle that so we installed the license plate as it should be.
The other side of the GT750, notice the license plate, some installed the license plate with 5 mm difference on left and right side. As i am a technician i can not handle that so we installed the license plate as it should be.
When we did the yearly maintenance we discovered that the rear tire was 25years old, TO OLD. We informed the client and we had to replace the rear tire by a new one.
When we did the yearly maintenance we discovered that the rear tire was 25years old, TO OLD. We informed the client and we had to replace the rear tire by a new one.
So we solved the problem by installing the clutch cable lever in the right position by turning the mechanism 180dg. Now you can use the clutch easily.
So we solved the problem by installing the clutch cable lever in the right position by turning the mechanism 180dg. Now you can use the clutch easily.
The SECOND problem: The installed clutch cable was much to long, 15cm longer than a genuine clutch cable. On routing the clutch cable on the GT750 the cable makes to sharp angles and the clutch cable won't move anymore.
The SECOND problem: The installed clutch cable was much to long, 15cm longer than a genuine clutch cable. On routing the clutch cable on the GT750 the cable makes to sharp angles and the clutch cable won't move anymore.
We started to re-route the cables, we noticed that it was really imposible to activate the clutch. Tried several things to repair that. At least we opened the round clutch cover and found the FIRST problem: Wrong installed clutch cable lever. The lever should be in the horizontal position.
We started to re-route the cables, we noticed that it was really imposible to activate the clutch. Tried several things to repair that. At least we opened the round clutch cover and found the FIRST problem: Wrong installed clutch cable lever. The lever should be in the horizontal position.
Wrong routed cable on the clutch side. Take a notice of the clutch cable, also wrong routed.
Wrong routed cable on the clutch side. Take a notice of the clutch cable, also wrong routed.
Wrong routed front brake hose and steering switch cable. We re-routed the brake hose and steering switch cable, installed the front brake switch and did the maintenace on the frontbrakes by replacing the brake fluid.
Wrong routed front brake hose and steering switch cable. We re-routed the brake hose and steering switch cable, installed the front brake switch and did the maintenace on the frontbrakes by replacing the brake fluid.
Overview of the wrong routed steering switch cables and brake hose. All the cables are hanging on their connections in the switches, you can imagine that the cables will break.
Overview of the wrong routed steering switch cables and brake hose. All the cables are hanging on their connections in the switches, you can imagine that the cables will break.
After all radiator repaires were done we installed the radiator subtank and connected the sub tank to the radiator.
After all radiator repaires were done we installed the radiator subtank and connected the sub tank to the radiator.
SITE UPDATE 20102025: We repaired the clients own radiator. The radiator by removing the rests of the radiator sub tank connection on the lower side and installed a banjo bolt connection and nylon sealing washers
SITE UPDATE 20102025: We repaired the clients own radiator. The radiator by removing the rests of the radiator sub tank connection on the lower side and installed a banjo bolt connection and nylon sealing washers
Broken radiator sub tank connection, we need to repair this of course. We drilled a 6mm hole filed the outside welding en used gasket rings, a banjo bolt with a securing nut and a banjo connection for the repair.
Broken radiator sub tank connection, we need to repair this of course. We drilled a 6mm hole filed the outside welding en used gasket rings, a banjo bolt with a securing nut and a banjo connection for the repair.
Broken radiator sub tank connection, we need to repair this of course. We drilled a 6mm hole filed the outside welding en used gasket rings, a banjo bolt with a securing nut and a banjo connection for the repair.
We found that the radiator sub tank connection on the radiator was clogged by corrosion, when we tried to unclogg the connection this part separated from the radiator. We need to repair this of course.
We found that the radiator sub tank connection on the radiator was clogged by corrosion, when we tried to unclogg the connection this part separated from the radiator. We need to repair this of course.
When we drained the coolant, we found that there was still coolant in the radiator sub tank, so the cooling system is clogged somewhere. Sadly the radiator sub tank has been repaired in the past. We will replace the radiator sub tank.
When we drained the coolant, we found that there was still coolant in the radiator sub tank, so the cooling system is clogged somewhere. Sadly the radiator sub tank has been repaired in the past. We will replace the radiator sub tank.
We removed the radiator sub tank because we drained the coolant but there was still coolant inside the radiator sub tank.
We removed the radiator sub tank because we drained the coolant but there was still coolant inside the radiator sub tank.
New OEM SUZUKI hose installed. Clamps installed on the right position.
New OEM SUZUKI hose installed. Clamps installed on the right position.
CAUTION: You have to take care when you fasten the hose clamps. You should check if the clamp is on the right position so it won't leak.
CAUTION: You have to take care when you fasten the hose clamps. You should check if the clamp is on the right position so it won't leak.
We had to replace the TO SOFT cooling hoses. It was possible that the installed hoses would give cooling problems when driving. When we removed these hoses we found severe corrosion, this because the clamp wasn't fastened enough. We removed the corrosion by cleaning.
We had to replace the TO SOFT cooling hoses. It was possible that the installed hoses would give cooling problems when driving. When we removed these hoses we found severe corrosion, this because the clamp wasn't fastened enough. We removed the corrosion by cleaning.
Removed the frontwheel to repair/exchange the speedometer gear box assy.
Removed the frontwheel to repair/exchange the speedometer gear box assy.
Removed the frontwheel to repair/exchange the speedometer gear box assy.
Speedometer gear box assy, we needed to remove the frontwheel to inspect the threading. Sadly we needed to replace the compleet speedometer gear box assy.
Speedometer gear box assy, we needed to remove the frontwheel to inspect the threading. Sadly we needed to replace the compleet speedometer gear box assy.
SITE UPDATE 30092025: Repairing the speedometer gear bos assy, the threading is severe damaged and you can't connect the speedometer cable on the gear properly.
SITE UPDATE 30092025: Repairing the speedometer gear bos assy, the threading is severe damaged and you can't connect the speedometer cable on the gear properly.
With a petrol botlle connected on the carburetors we have started the engine and the engine is "alive" again. Now we can synchronize the carburetors and adjust the air mix screw for the right exhaust temperature.
With a petrol botlle connected on the carburetors we have started the engine and the engine is "alive" again. Now we can synchronize the carburetors and adjust the air mix screw for the right exhaust temperature.
Installed the rebuild carburetors, we have to check the left carburetor again because it has leaked some petrol.
Installed the rebuild carburetors, we have to check the left carburetor again because it has leaked some petrol.
Finished carburetors: You can see the difference immidiately. Note the right position of the rubbers for connecting to the intake.
Finished carburetors: You can see the difference immidiately. Note the right position of the rubbers for connecting to the intake.
Finished carburetors: You can see the difference immidiately.
Finished carburetors: You can see the difference immidiately.
Finished carburetors: You can see the difference immidiately.
Finished carburetors: You can see the difference immidiately.
Disassembling the carburetors: Nope we can't use these floats, one is leaking, one will leak within some time the last one is imploded. So we have to replace the floats by new aftremarket floats.
Disassembling the carburetors: Nope we can't use these floats, one is leaking, one will leak within some time the last one is imploded. So we have to replace the floats by new aftremarket floats.
Disassembling the carburetors: See the difference on the left a dirty carburettor and on the left a clean caeburettor.
Disassembling the carburetors: See the difference on the left a dirty carburettor and on the left a clean caeburettor.
Disassembling the carburetors: All three disassembled carburettors.
Disassembling the carburetors: All three disassembled carburettors.
Disassembling the carburetors: Cleaning the carburetors, see the difference. It is a lot of work to clean and poke every hole, it will take an hour to clean ONE carburetor.
Disassembling the carburetors: Cleaning the carburetors, see the difference. It is a lot of work to clean and poke every hole, it will take an hour to clean ONE carburetor.
Disassembling the carburetors: The carburetors have been rebuild before but we found screws which were loose. Image what happens when the screw is getting into the engine.
Disassembling the carburetors: The carburetors have been rebuild before but we found screws which were loose. Image what happens when the screw is getting into the engine.
Disassembling the carburetors: The carburetors are very dirty due to corrosion and petrol resedue.
Disassembling the carburetors: The carburetors are very dirty due to corrosion and petrol resedue.
Disassembling the carburetors: Someone lost a spring for the synchronizing adjustment.
Disassembling the carburetors: Someone lost a spring for the synchronizing adjustment.
Disassembling the carburetors: This should always be on the lowest point in the direction of the intake, so the petrol can flow in the cylinder.
Disassembling the carburetors: This should always be on the lowest point in the direction of the intake, so the petrol can flow in the cylinder.
Disassembling the carburetors. Take a good look on this photo: You can see already that the floats DON't have the same heigts, the center carburetor was 5mm lower than Left and Right. Also you can see that the carburetors are very dirty and haven't seen petrol for a long time.
Disassembling the carburetors. Take a good look on this photo: You can see already that the floats DON't have the same heigts, the center carburetor was 5mm lower than Left and Right. Also you can see that the carburetors are very dirty and haven't seen petrol for a long time.
Of course we tested all cylinders, in this photo's we tested the LEFT cylinder. We found nothing wrong on all the three cylinders. We will inform the client about checking the gearbox oil more often.
Of course we tested all cylinders, in this photo's we tested the LEFT cylinder. We found nothing wrong on all the three cylinders. We will inform the client about checking the gearbox oil more often.
Close up of the closed inlet port and connected pressure pump.
Close up of the closed inlet port and connected pressure pump.
Closed exhaust port of the LEFT cylinder.
Closed exhaust port of the LEFT cylinder.
As we want to know where the 1200cc gearbox oil went we did a pressure test on the crankshaft seals. the pressure we use is 0,5bar. When the crankshaft seals are OK the pressure in the cylinder should stay on 0,5bar.
As we want to know where the 1200cc gearbox oil went we did a pressure test on the crankshaft seals. the pressure we use is 0,5bar. When the crankshaft seals are OK the pressure in the cylinder should stay on 0,5bar.
We made an adapter for closing the inlet port and to provide the cylinder with the 0,5bar pressure.
We made an adapter for closing the inlet port and to provide the cylinder with the 0,5bar pressure.
Of course you have to close the exhaust port for testing the cylinder, closing the SRIS valve hole and the connected SRIS hose before you can do the test.
Of course you have to close the exhaust port for testing the cylinder, closing the SRIS valve hole and the connected SRIS hose before you can do the test.
We drained the gearbox oil. This is what was in the engine. We put this gearbox oil in an empty oil cannister, there was 800cc left in the gearbox, give it 1000cc because there is always oil left in the engine. There is in total 1200cc gearbox oil gone or not enough gearbox oil filled.
We drained the gearbox oil. This is what was in the engine. We put this gearbox oil in an empty oil cannister, there was 800cc left in the gearbox, give it 1000cc because there is always oil left in the engine. There is in total 1200cc gearbox oil gone or not enough gearbox oil filled.
Duh... just a little gearbox oil drip at the tip of the screw driver. Where is all the gearbox oil? This is not a good oil level.
Duh... just a little gearbox oil drip at the tip of the screw driver. Where is all the gearbox oil? This is not a good oil level.
On an unknown GT bike we always do a gearbox oil level check. We always use a screw driver as a kind of dipstick, on a normal level there should be approximately 1cm of gearbox oil on the tip of the screw driver.
On an unknown GT bike we always do a gearbox oil level check. We always use a screw driver as a kind of dipstick, on a normal level there should be approximately 1cm of gearbox oil on the tip of the screw driver.
We did a INSIDE engine check of the pistons. Nothing wrong with this.
We did a INSIDE engine check of the pistons. Nothing wrong with this.
We did a INSIDE engine check of the pistons. You also see the connecting rod, piston in the upper position.
We did a INSIDE engine check of the pistons. You also see the connecting rod, piston in the upper position.
We did a INSIDE engine check of the pistons.
We did a INSIDE engine check of the pistons.
We did a INSIDE engine check of the pistons.
The oil hose should be routed at the back side of the oil pump.
The oil hose should be routed at the back side of the oil pump.
Wrong routed 2stroke oil hose from the 2stroke oil tank to the oil pump. CAUTION: It is possible that you get a oil startvation on the engine when the oil hose has a closing bent.
Wrong routed 2stroke oil hose from the 2stroke oil tank to the oil pump. CAUTION: It is possible that you get a oil startvation on the engine when the oil hose has a closing bent.
But after the spaghetti moment we have a routed wire loom as it should be.
But after the spaghetti moment we have a routed wire loom as it should be.
So we create spaghetti first.
So we create spaghetti first.
BAD elektricity, the plus wire needs to be replaced. Look at the wire loom, without the loose wires you can get chafings, as it is installed, so we need to correct this. We also replaced the MINUS connection because it was to old and to damaged.
BAD elektricity, the plus wire needs to be replaced. Look at the wire loom, without the loose wires you can get chafings, as it is installed, so we need to correct this. We also replaced the MINUS connection because it was to old and to damaged.
First we checked the ignition, this ignition plate looks like it swam in salt water, severe corrosion of all the parts. This means we need new contactpoint or better new elektronic ignition.
First we checked the ignition, this ignition plate looks like it swam in salt water, severe corrosion of all the parts. This means we need new contactpoint or better new elektronic ignition.
Nothing wrong with 2stroke oil problems on this GT750. We noticed that all the four exhaust pipes were VERY DRY, we mean not really oily as it should be. It is possiblem that the engine runs to lean.
Nothing wrong with 2stroke oil problems on this GT750. We noticed that all the four exhaust pipes were VERY DRY, we mean not really oily as it should be. It is possiblem that the engine runs to lean.
At www.knalnaarpotz.nl we NEVER will start an UNKNOWN Suzuki 2STROKE bike. This because the bike comes to us due to repairs. As we don't know what's wrong we FIRST do a draining of the carters of the engine.
At www.knalnaarpotz.nl we NEVER will start an UNKNOWN Suzuki 2STROKE bike. This because the bike comes to us due to repairs. As we don't know what's wrong we FIRST do a draining of the carters of the engine.
This GT750-B is well rebuild, but needs some more TLC.
This GT750-B is well rebuild, but needs some more TLC.
This GT750-B is well rebuild, but needs some more TLC.
This GT750-B is well rebuild, but needs some more TLC.
This GT750-B is well rebuild, but needs some more TLC.
Just for tagging: Motor revisie GT750 GT550 GT380 T20 T500 GT2500 T350 krukas revisie cilinder boren en honen polijsten onderdelen waterpomp zuigers onderhoud reparatie vervanging.
Just for tagging: Motor revisie GT750 GT550 GT380 T20 T500 GT2500 T350 krukas revisie cilinder boren en honen polijsten onderdelen waterpomp zuigers onderhoud reparatie vervanging.
SITE UPDATE 15092025: This restored bike won't run properly anymore. Our job is to get the bike on the road again.
SITE UPDATE 15092025: This restored bike won't run properly anymore. Our job is to get the bike on the road again.

Parts for this bike

All parts Suzuki GT750

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