billythewhizz said:

The walls of the bore appear to be smooth - how do you know if they need to be rebored or honed and just replace the pistons?

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is there a step near the top on exhaust side of the bores, if there is it shows wear otherwise you measure the bore side ways then front /back just below were the top ring sweeps,if they differ thats the wear, bores wear side to side not front to back, with that measurement you can compare that to new piston diameter taken at 90 degrees to the gudgeon pin at bottom of skirt,the difference between the 2 should be within piston clearance spec, if its near its worth honing if clearance is too much a rebore is required

billythewhizz said:

The walls of the bore appear to be smooth - how do you know if they need to be rebored or honed and just replace the pistons?

Click to expand...

If they are smooth as in polished with no radial scratch marks then they are worn out, it there are quite a few radial scratch marks ie a sort of sprial scratching theres a chance a light hone will do the job.