Found scuffing on the pistons?

[Jpich85]

I've started stripping the engine down on my gsxr750 1985 it's my first time doing it so I'm not sure what's acceptable and what's not. 

I've found some scuffing on the pistons and wanted to ask if this just normal wear for a old bike or something I should address?

I can't really afford to go to mad on this bike so I just wanted to check if I can still use them?

Also I can't get 4 of the studs out, are there any tips to help get them moving?

 

[TonyGee]

the pic is a bit blurry when i zoom in but it doesn't look great !!!  whats the bore like ? 

[TLRS]

Any fuel in the oil?

[Jpich85]

Thanks guys, I'll check the bore over and see what it's like and I'll check the oil too, I'm doing a full strip down and getting the cases ceroketed so hopefully after I build it back up it'll be in better shape, I just wondered if I can still use these

[HWB]

Engine is shot mate

[Buzuki]

Jpich85

Measure piston outer diameter down by lower part of the skirt and also measure cylinder bore inner diameter upper close to cylinder head , than calculate the difference , piston to cylinder tolerance limit is 0,120mm , if your measured difference is inside of this 0,120 from factory limit you can reuse that piston and cylinder block again , just use some extra-fine tool to rectify and polish that piston surface scuffing and scratches , of course all others piston dimensions have to be carefully measured and checked , all that is already very well described and explained in original Suzuki service manual ,

btw , IME those Suzuki pistons are from the highest quality and over the time wear is minimum , so usually they can be reused again in combination with new piston rings set .

Edited December 21, 2022 by Buzuki