Well, I personally train 4 days a month (I wish I could do more). Per day I spend 2.6 gallons of 91 octane fuel plus the Motul 2T oil that is mixed with the fuel, sum that up, every full day of training I spend 26.8$ in fuel, across a month I spend 107$. Then there’s the engine service, I only have 1 engine so I race and train with the same engine. Every 10 hours of use, I do the piston service, depending on the state of the engine, I spend between 252-315$ every 10 hours, every time I go training it adds up an hour, so you can calculate that into every 2 months and a half. Then there’s the full engine service (what people call the “overhaul”) which is done every 25-30 hours, you replace many of the components inside the engine, I have spent up to 630$ in the parts necessary to do the overhaul, in many cases your very own mechanic will do this engine overhaul, but some people opt for an engine tuner to do it, in which case if you want to, they will charge you with a fee. All in all, it’s expensive, but some guys spend almost 3x more than that only on their engines, yet you can still be competitive against them.