Originally Posted by gefr
In case this is the culprit though, the new seals will rapidly disintegrate within a month or so, operating in the damaged cylinder surface. These cylinders are colored with a hard paint. When this gets damaged, the seal gets eaten and leaks. The cylinder then needs replacement. I had good luck resleeving this with stainless steel sleeve and going down in diameter. I used lighter KTM bikes' clutch piston. The effect is holding nicely till now.
If the surface is damaged then it's a good idea to resleeve or replace the master. Thank you for correcting that.
'03 KTM 250sx -- '05 KTM Adventure 950
'00 KTM 250sx -- '03 KTM 450sx -- '03 Yamaha R6 -- '08 KTM SuperDuke R --- '13 KTM 690 enduro R