Originally Posted by maxwell123455

Hi and welcome to the forum

The front tyre size is ok but the rear should be 130/80 17, this might be causing some of your problems and also the tyre pressures should be run at about 33psi.

How many miles has the bike on it? If its second hand and a bit used (10k+) the front wheel bearings might be gone (people get too close with powerwashers and blow the grease out and they heat up and collaspe) or the head race bearings could be a bit loose, someone doing alot of wheelies will loosen these up.

Also with this cold/greasy/rubbish weather we are having a bikes handling is never going to be 100%