I moved your topic here as it is easier to find
If it's worn as in the pic I would choose 3 as the best option.
Honda P/N 91001-HP1-601
30X76X19 It is 4mm larger than a KX500 but all the other sizes are the same.
Fits the following:
Honda ATV 2006 TRX450ER A CRANKCASE ('06-)
Honda ATV 2006 TRX450R A CRANKCASE ('06-)
Honda ATV 2007 TRX450R A CRANKCASE ('06-)
Honda ATV 2007 TRX450ER A CRANKCASE ('06-)
Honda ATV 2007 TRX450ER 3A CRANKCASE ('06-)
Honda ATV 2007 TRX450R 3A CRANKCASE ('06-)
Honda ATV 2008 TRX450ER 3A CRANKCASE ('06-)
Honda ATV 2008 TRX450ER A CRANKCASE ('06-)
Honda ATV 2008 TRX450R A CRANKCASE ('06-)
Honda ATV 2008 TRX450R 3A CRANKCASE ('06-)
Honda ATV 2009 TRX450R A Crankcase
Honda ATV 2009 TRX450R 3A Crankcase
Honda ATV 2009 TRX450ER A Crankcase
Honda ATV 2009 TRX450ER 3A Crankcase
Honda ATV 2012 TRX450ER 3A - TRX450ER Crankcase
Honda ATV 2013 TRX450ER AC Crankcase
Honda ATV 2013 TRX450ER 3AC Crankcase
Honda ATV 2014 TRX450ER AC Crankcase
Honda ATV 2014 TRX450ER 3AC Crankcase
This Honda 91001-MEY-671 BEARING, RADIAL BALL (30X76X19) fits the following models and components:
Honda Motorcycle 2005 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2005 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2006 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2006 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2007 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2008 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2009 CRF450X A - CRF450X Crankcase
Honda Motorcycle 2012 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2013 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2014 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2015 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2016 CRF450X AC - CRF450X Crankcase
Honda Motorcycle 2017 CRF450X AC - CRF450X Crankcase
Some claim that the Suzuki LT500 bearings will also work.
IF that is true (I have not verified the bearing size yet) then these should fit.
Suzuki P/N 09262-30076
Suzuki ATV 1987 QUADRACER - LT500R Crankshaft
Suzuki ATV 1987 QUADRACER - LT500RL Crankshaft
Suzuki ATV 1988 QUADRACER - LT500RL Crankshaft
Suzuki ATV 1989 QUADRACER - LT500RL Crankshaft
Suzuki ATV 1990 QUADRACER - LT500RL Crankshaft
Suzuki Motorcycle 1978 SP370 Crankshaft
Suzuki Motorcycle 1980 GN400T Crankshaft
Suzuki Motorcycle 1980 GN400TX Crankshaft
Suzuki Motorcycle 1980 GN400XT Crankshaft
Suzuki Motorcycle 1979 SP370 Crankshaft
Suzuki Motorcycle 1980 GN400XX Crankshaft
Suzuki Motorcycle 1980 SP400 Crankshaft
Suzuki Motorcycle 1981 GN400T Crankshaft
Suzuki Motorcycle 1981 GN400XX Crankshaft
Suzuki Motorcycle 1981 GN400TX Crankshaft
Suzuki Motorcycle 1981 GN400XT Crankshaft
Suzuki Motorcycle 1982 GN400T Crankshaft
You might get away with option 2 but I would use a retaining compound such as LOCTITE 660.
LOCTITE 660 is designed for the bonding of cylindrical fitting parts, particularly where bond gaps occurs such with worn parts, without the need for remachining.