350x chain keeps coming off

[Nesbitt60]

So I just got back from glamis yesterday and my bike ran great all the way until the second day my chain came off and cracked my case which it has done before and I don't understand because I made that chain a little to tight cuz I would have rather had the possibility of snapping than coming off and I was racing up comp and it came off the front sprocket does anyone know what it could be cuz the bike never had a problem of all dayup olds and down sand highway

[scuba]

First thing , GET A CASE SAVER !!!!!

as far as the chain coming off, I will assume the chain isn't stretched and the sprockets are not worn out. Then I would first look into the swing arm pivot and carrier bearings. If they are worn out, they will allow the chain to come out of alignment, thus kicking the chain off. And for it coming off of the front sprocket, I have always run a case saver, but without it, it would allow the chain slack to slip off of it also.