Suzuki GT/T500 engine tune-up and maintenance details

Suzuki GT/T500 engine tune-up and maintenance details


Carburetor specs T500III, R T500J T500K, L, M, GT500A, B
Carburetor VM32SC VM32SC VM32SC
Main jet 150 150 97.5
Needle jet P-5 P-5 (right) P-4 (left) P-4
Needle (last no. indicates needle clip position counting from top groove 5FP8-3 5FP8-3 5FP17-3
Pilot jet 30 30 30
Throttle slide 2.5 2.5 2.5

Model T500, R, J T500K T500L T500M GT500A, B
Pilot screw turns out 1.25 1.5 1.5 1.5 1.5

Model T500, R T500J, K, L, M GT500A, B
Float height 27mm 27.3mm 25.8mm


Model T500, R, J T500K T500L T500M GT500A, B
Spark plug (NGK/ND) B-77HC/W24FS B-77HC/W24FS B-77HC/W24FS B-7HS/W22FS B-7HS/W22FS
Spark plug gap 0.6-0.7mm 0.6-0.7mm 0.6-0.7mm 0.6-0.7mm 0.6-0.7mm
Point gap 0.3-0.4mm 0.3-0.4mm 0.3-0.4mm 0.3-0.4mm not applicable
Ignition timing (BTDC) 3.4mm 3.4mm 3.44mm 3.44mm PEI – 2.93 mm

Piston clearances
(std bore 70mm, 1st OS 70.5mm 2nd OS 71mm)

Piston clearance (measuring from bottom edge of skirt, 90 degrees from the wrist pin T500III-M, GT500A, B
Piston standard clearance 0.065-0.075mm
Piston servicable limit 0.25
Ring end gap 0.20-0.36mm
Ring servicable limit 1.0mm

Various Capacities

Capacities T500 T500II, III, R, J, T500K, L, M GT500A, B
Gearbox (transmission), including clutchcase 1200cc standard (warning, modify gearbox to hold at least 1400cc) 1200cc standard (warning, modify gearbox to hold at least 1400cc) 1400cc standard 1400cc standard
Front fork (each leg) 220cc 220cc 220cc 220cc
Oil tank 2,500cc 1,800cc 1,800cc 1,800cc
Fuel tank 14 litre 14 litre 17 litre

Suggested lubricants

Engine oil – good quality two-stroke SAE30 oil (synthetic oil is perfectly OK)
Gearbox (transmission) – SAE 20/40W multi-grade oil (but not friction modified if possible)
Front forks – SAE 10/30W multi-rade oil, ATF (auto transmission oil) or a good quality fork oil
Drive chain – SAE30 motor oil or special chain lubricant
Fuel – 85-95 octane

Tyres and electrics


3.25 x 19in front / 4.00 x 18 rear
Tyre pressure 22-24 psi front / 26-34psi rear
Battery 12V 5AH
Headlight globe 12V 35/25W
Tail-light/brake-light 12V 4/32cp
Indicators 12V 32cp
Fuse 15amp glass fuse
Instrument globes 12V 3,4W

Clutch and general adjustments


Suzuki T 500/GT 500

Clutch plates fibre std. = 3,5 mm / change at : 3,2 mm
Clutch plates steel std. = 3,5 mm / change at : 3,2 mm
Clutch springs std. = 40,4 mm / change at: 39,0 mm
Clutch lever free play 4 mm
Front brake free play 20 mm
Rear brake pedal free play 20 – 30 mm
Rear chain free play 25 mm measured in middle of chain


Author: muzza

2 thoughts on “Suzuki GT/T500 engine tune-up and maintenance details

  1. Hi, I have been left by my late brother, 2 Suzuki T500 / GT500 race bikes, the GT is all most ready, the T500 is to go in a new Seeley Suzuki frame, he was working on them for over 20 years, before he passed away, I have made it my task to finish them both, BUT, the T500 engine he put 750 con rods in it, and some engine builders I have asked to finish building the engine, won’t touch it, as it will need an adapter plate made for it to lift the barrels up, so the pistons won’t hit the heads, they tell me to get 500 con rods then they will do it, but I wan’t to carry out what my brother started.
    he was all ways looking where he could get an extra hours power from. what does putting 750 rods into a 500 engine do, and is it worth it.
    thanks for reading this, and thanks to any one who can help
    regards, Andrew Faulds

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