Broken plug = Re-Build

plug appears burned off, headgasket is burned thru, that's exactley where most pistons burn away from detonation. dont see any signs of mechanical damage in pics. all 3 of these are strong indicators of detonation. get ur injectors flowed/tested. suspect a faulty injector/fueling problem on that cyl if running stk ignition timing. make sure tune spot on.

yup^^^^

Would like to add some info but its already been said. Detonation for sure. Too much cylinder pressure and not enough octane broke the plug. What octane were u running?

Thanks for the input Iv taken it onboard, the injector is most likely Iv got another set to put in ignition is at +2% & the pump fuel over here is 97 Ron. I wouldn't mind finding out about after market head bolts to get more torque down. So it's start RE-build time I'm hoping Wossner can match a piston otherwise it's a set off 4 ?

nothing wrong with the hg u were running, pics clearley indicate adequate pth and compression not the issue with 97 ron. pull the timing, maybe even retard a degree. think u will find the bike even faster, been my experience. got to the point i have injectors professionally cleaned/flowed on all my builds along with a hi flow fuel pump after too many fueling issues on the dyno. good insurance, makes for solid hp and reliability. stk. head studs will hold all tuning factors corrected.

YUP. That missing section of piston right there is the first thing to go if you detonate/melt a chamber.... it gets worse from left to right on these motors (as you get closer to the timing chain).... take a good hard look at the other pistons around the valve relief area; any deformation and/or lifting will show that it's an overall tune problem. If the rest are perfect you may have a bad single injector like Gaz stated. Have those guys cleaned/flow checked!

Spot on guys three pistons are unmarked its just the 1 its defo an injector problem, the bummer is i just been told wossner dont have a match for that set i gotta buy 4 off em :angryfire: i just put the stock engine in her tonight so i can still ride while i re-build this fucker thanks all for your help :notworthy: