I sent an email to to boygofast customer service regarding 80cc engine firstname.lastname@example.org
and explained with pictures and words saying that the nut that goes under the clutch plate kept coming loose and that the slot behind the washer was empty with no wood ruff key. I sent him pictures showing the problem and he sent me an email with pictures with a hammer saying to hit the plate in the middle ? I dont think that sounds right. Below is the email he sent explaining.
Please open the clutch cover ( which is 5 bolts attached)
Turn the middle of the flower nut right or left to make it tighten or loose.
Some time the curve on the plate is not deep enough. So hit the middle of the plate to make it little deeper (about 1-2mm), then adjust the flower nut. ( this not happen usually, but in case)
I attach few pictures, u can take a look
and also please check the flower nut if thread no good
If you have any question, feel free to email us