Hi Rhys. I've had many of both and still have two TSs.

The TF & TS 185 motors are almost identical. You probably know the TF (Suzuki called it the MudBug) was for farm work and had some minor tuning and gearing changes to make it more suitable for that. The barrel porting is different, especially the exhaust port, and it has a smaller carb. This have a noticeable increase in low end torque. It has a smaller front sprocket and larger rear sprocket for lower and slower gearing for climbing steep hills, and for dawdling behind walking herds of livestock. Other than that, the motors are the same. The TS185ER was about 18.5hp and the TF was just over 13hp.
I had my TFs for dairy farm work and they were just the best farm bikes. I had a TS barrel that I'd had ported slightly giving about 20hp, with a correctly jetted carb attached. I used to use this for trail riding. When I was going trail riding, I'd undo the exhaust studs, head studs, plug lead, and air filter boot on the TF motor and pull the barrel and carb off. The tuned TS barrel and carb would go on giving a decent increase in power. I could do it in about 10-15 minutes.
Another tip with these motors is NEVER run them on pre-mix fuel, except for the first start after a rebuild. The CCI oil injection system feeds into two points. One is directly to the piston, and the other to the left main crank bearing and the big end bearing directly. They will run for a surprising amount of time on pre-mix but these two bearings WILL fail in time. Also the CCI system automatically varies the oil to fuel ratio according to the load on the motor, from a low of about 110:1 up to about 25:1 under full throttle. You get less carbon and oil residue build-up on the piston, exhaust port and inside the exhaust pipe and silencer.
Hope this helps. Where are you? The TF was sold mainly in New Zealand and Aussie.

Best regards
Nigel in NZ.

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