Your motor seizing up for a little bit ata a time is a bad sign. Most bikes run awesome right before they have major problems. The next time it 'locks up' kill the bike and take off the flywheel cover.
Put the bike in neutral, and try to roll the crank over via the flywheel nut. That will tell you if it's a top end issue, or tranny.
Regardless of that finding, you need to remove the clutch cover and inspect the gears on the outside by the clutch. Check for sever wear, teeth missing, or obvious grinding. Check the kickstart gear, drive gear, kicker gear, idler gear.
Do you get the grinding sound as soon as the bike starts? Or during a ride?
Put the bike in neutral, and try to roll the crank over via the flywheel nut. That will tell you if it's a top end issue, or tranny.
Regardless of that finding, you need to remove the clutch cover and inspect the gears on the outside by the clutch. Check for sever wear, teeth missing, or obvious grinding. Check the kickstart gear, drive gear, kicker gear, idler gear.
Do you get the grinding sound as soon as the bike starts? Or during a ride?