gsxr starter motor question

[spar382]

Hi I got a 1990 gsxr 400 sp model and been trying to get a starter motor that fits.
I tried one supposedly from a gk73a and from a gk76a but they are both too big.
The diameter of the splines rod should be 10mm on mine but the above 2 have been 15mm.
for starters does anyone have one and secondly can anyone tell me if Im going to need a special sp model starter motor.
thanks

[wowzer]

I no ive got one on an engine not sure on the size though it is an sp ill have a look when i go to my mates house thats where my spare engine is

[spar382]

its ok i got this sorted now. I went through 3 starter motors from breakers and then found one on ebay for 10 quid and it fits and works great.
all the breakers told me there is only 1 kind of starter motor for a gk73 but this is rubbish, there are definatly 2.(one slightly smaller)