G'Day
The Seal on a 55 or 54 engine is not a Seal but a O-ring
Part No 0770160030 use the number a a KTM shop?
you also need the bush as well Part No 550 33 0069 000
Or
you can go to a Auto shop and buy 2 o-ring 16 x 3 and fit the 2
o-ring side by side and push the Kickstarter on Hard .
you may need to push the 1st o-ring in with somthing to get it
and the 2nd will keep it in place .