Runner 180 crank snapped help

Hi I have a runner 180 2t
Riding to work hear a loud squeaking noise so I pulled over turned the bike off turned on again turned the bike then allow bang

Got the bike home took the engine case off as I did the area it's a starter motor all fell out
The crank has snapped off

So then I took off the flywheel cover to see if it was seized but the piston
Is moving thank god


Any one no y this would happen
?????

Just. Worried if of got another crank it would happen again

 

What mods have you done to it?

 

That's what they do, I've known 125's to brake off! It's the weight of variator on the crank that's the cause.Just replace the crank/mains/seals/water pump.

 

Mods are
172 bittle head pm
Massio Variate
Srt fly wheel
25mm carb

 

ouch.good job you wasn't moving when that let go.doppler cranks are good for 18000rpm but dunno if they would stop that happening
can/do vatiators need balancing?honestly never seen a crank snap outwards of the mains.not heard anyone have issues with malossi either.

 

Seen a few pitbikes with the crank snapped in the same place........

 

im assuming this is a standard crank.

 

Yes crank was standard

 

Piaggio build quality!

 

right.bit worried that it was an after market quality job snapping.

 

Any ideas too wat crank to buy ????

 

have a look on pedparts and donotlink pedstop.S6 looks a nice bit of kit..motorforce..nuraku...stay away from Standard ones if you wanna cane it and not have to think about it letting go. £100-125 for 50cc
dunno for a 125/172 converted.

 

mmM.typed donotlink pedstop and it got changed to donotlink but when i went to edit...it showed adrenaline. Are we being censored??

 

did it again.i think you know where i mean though.

 

Yer I was super pissed

 

Looked on pm tuning
Top race crank 129
Pm tuning 178 ???

52mm or 54 mm ????

 

take the head off and measure your stroke with a good metal ruler or a depth gauge

 

Std stroke is 52mm.

 

So wat u guys think as to wat crank to buy
Pm tuning
Or
Top racing

52 or 54 ????