yx 150cc gear box vs lifan 140cc gearbox

[50's_feind]

Hi All i currently own a Lifan 140cc custom built bike and was wondering if i put a yx150cc engine in it how are the gearboxs on that engine as mine i have herd are weak as i currently run the 1P55FJM in my bike i was originally going to upgrade to a 1P56FJM as i know the gear box in them is stronger, but now the YX150cc is out and available i was wondering is the gearbox in them stronger than the 1P56FJM.
Thanx guys any information on this engine would be good

 

[themountain]

as far as now they hold up well even with 187cc +R build...the weak part is the clutch!!

 

[1fifty1wheel]

second that,
had the 150 for a while no box probs, just clutch basket dramas through sand.