Standard tyre sizes gsxr 250 j73a?

[mannanin]

hi all

got myself a project gsxr250r 73a 1989 model

the one with the split seat and 18 inch rear rim

Whats the standard sizes on this bike as the guys squeezed a 120/70 on the front which cant be right?

thanks

[MSTRS]

The 89 is the J model, and has 17 b+f. Front tyre should be 100/80.
Made years 1987-90, models H, J, K, L - all had 17in rims. A retro model? (1994 no letter designation) seems to have had an 18in rear. http://www.gsx-r.eu/History_gsxr250.html