Hi all, just picked a little Beta rev 50 up for my son to start trials on. Does anyone know what sort of temp the fan should come on? He rode it yesterday and it didn’t come on at all but it was a cold day. The fan works if I close the circuit at the thermostat so maybe it’s duff thermostat? Other question is what sort of premix ratio is good for these little Betas? 

Regards Ian 

Most trials bikes seem to come on around 140 F.  I don't know if the 50 is the same.  For fuel mix if he is riding it like a trials bike I would mix at 75:1.  Beta calls for 1.5% oil.  If he's using it for a trail bike and flogging it I'd mix 50:1. 

The 50 is based on the 80 Jr in case that is any help.

Have fun! 

Thanks, he’s only plodding around on it so definitely not flogging it just yet. I’ll check the thermostat and go from there 👍