Would anyone happen to know the standard jet sizes and needle position for a TY250a, please? The bike has the standard TK carb on it. Thanks

I'll have a look this afternoon and post them up but you should be aware that the jetting numbers for that TK carby do not necessarily relate to Mikuni numbers.

This is from the Yamaha TY250A parts book:

Pilot jet #50

Main jet #114

Slide cutaway #3.0

Slide needle 5C92-4

Needle jet is called "nozzle-main" Yamaha part number 434-14341-00

This is from a tune-up book:

TY250A 434-000101 onwards

Carby model Teikei Y26P

Float level 21mm

Starter jet No 90

Air jet 2.5

Air screw 2.5 turns

Pilot jet No 50

Main jet No 112

Jet needle/clip position 5C9Z-3

Cut-away No 3.0

Needle jet S-85

Thank you very much for that mate.