My son has a 2021 Tao Cheetah 125. The rear engine mount bolt keeps snapping. I've tried Grades 5, 8 and 10. All break within 20 minutes of light riding. Been through no less than 8 bolts. Son I'd afraid to ride because it always breaks. Any help would be appreciated. Thanks

 

Are you torquing them up correctly? Are the other engine mount bolts tight? Is chain over tightened? The rear bolt gets quite a lot of load as the chain is pulling against it, but the other mounting bolts should be sharing the load.

 

The other mounting (on top of engine) is tight. The rear bolt is only torqued to about 35 ft/lbs. Chain seems good, but will try to loosen a bit. Just didn't know if there would be another reason for it breaking.

 

I worked on a Buyang a while ago and the chain had bad tight spots, on examination the rear sprocket had been machined eccentric, this had been on since new, so Chinese manufacturing tolerances are not always good. Honda 350 head steady bolts are M8 and 24 ft/lb, though this is into aluminium and probably 88 quality. Other engine mounts are M10 and 40 ft/lbs.