Hi motor secure and no wear on the belt or motor, Bradster had been using it for half and hour stopped to let motor cool as bleeper sounding when he went back out, funny noise first then the belt came off, we do not have one of those strange mod things how would that work? we have a second sinclair that we had not tried until today found a fuse blown then tried it and the same thing the belt comes off. If you lift the wheel up off the floor it runs lovely. Brad is six stone not heavy. We have other spare parts and have changed cog belts etc and the same is still happening please help, bradster driving us mad he has the bug for them now and nothing else will do. thanks Lynne