At inspection though, the bore looks just fine and cleaned up well as did the piston.
The only way to get new seals is to buy an expensive piston and seal kit. About $OZ90-100 delivered from the UK.
https://www.motorworks.co.uk/rear-maste ... 791-2.html
...or $OZ112 delivered from Perth in Oz. https://www.munichmotorcycles.com.au/pr ... rhaul-kit/
I found some seals on ali express that I bought to look at and check out. Point of the post...here they are, so you know.
https://www.aliexpress.com/item/1005003 ... 1802eR0Ixp
The inner diameter is narrower than the oem seals. They're easy enough to fit though.
AE left, oem right. AE are slightly wider too but fit.
After splitting the rear caliper, cleaning the pistons, replacing the piston seals and the brake hose, the brake didn't improve at all. Some of you might be saying "yeah, well, they're a crap brake anyhow".
But, after the mc clean out etc they are better. As they say...ymmv !
