Scooterotica

took head off last night and the piston as a 5mm deep crater in it now ive had a few 172 t5s and always left timing standard and never had any trouble yet everyone was saying that I need to turn it 5 degrees clock wise so I done it and this happened ive asked around and most left timing as was

same set up mine left standard ran it 6 years clean as a whistle

Iv always left it as standard. No drama

mines standard timing as well, no bother.

Turning clockwise advances timing so if you've turned your stator by 5 degrees you're now running at 21 degrees BTDC, not good.
Retard it back to standard kid.

on the contrary ,turning your stator clockwise makes it fire closer to TDC ,anti clockwise would make it fire further away from TDC .
a std t5 timing is 16 degrees BTDC ,turning that clockwise by your 5 degrees would give you 11 degrees BTDC .
malossi recomend 14 on tuned /kitted set ups although a lot of folk do still keep it at the std 16 without any probs

although your timing is way out ,your holed piston may have been more likely caused by an air leak or fuel starvation

Bollox, that's why I've never been able to tell the time

Sorry, had a bit of a brain fart/senior moment.

thanks fellas ive took the barrel off and O.M.F.G the crown is disintegrating the exaust side realy it got me to clethorps no bother apart from on the a42 it back fired and poped a plug ......I thought if there was a air leak it wouldn't idle on tick over ...and there isn't any petrol comin out of the fly wheel side seal it does sound like ive fecked up with the timing don't it ...ive always left timing stock so why I didn't this time god nos

ive just ben reading on here about a lad who holed his piston on the way back fro m cleg and everyone as said did u fill up with shell fuel ..well I filled up in Newark and that was shell fuel surely it couldn't be that