Just changed the starter motor on my xl1200 limited 1999 and it's now making a grinding noise what should I do ?

The shaft that the solenoid pushes the gear up needs lubrication. If it's been grinding too long, the bearing in the starter is worn letting the armature to rub on the field frame. Might be time for a starter motor.

You will need to get a helper and get under the vehicle and touch & listen to the starter while some one else starts, runs the engine, and turns the vehicle off. Is the starter loose? PLEASE BE CAREFUL WHEN YOU DO THIS SO NO ONE GETS HURT. If you determine it is the starter you will need to change the starter. Also many starters will have a solenoid right on this starter, in some cases this solenoid is between starter and the battery, follow the heavy cable (positive cable) that runs from the battery to the starter to determine the location of the solenoid. If the solenoid is on the starter just change the complete starter. If the solenoid is between the starter and the battery and the starter is determined to be acting this way then try changing the solenoid first. If it is not the starter you will want to check everything on the front of the engine, alternator, water pump, idlers, pulleys, ac pump etc. I hope this helps.

broken tooth on the gear need a new starter

indicates that the starter motor is stuck in the ring gear
possibly faulty starter relay or starter solenoid
pull the starter as the pinion over ride clutch is probably damaged ( noise ) and have the start circuit and relay checked
have the starter bench tested for serviceability by an accredited auto electrician

if the starter is making a grinding noise when you turn the key, it's one of several possiblites. 1. Bad Starter. 2. Bad flywheel. 3. You need starter shims that fit between the starter and the motor. Most starters will bolt straight up but sometimes the gears get too close so you need to shim them apart.

Make sure your battery is fully charged and check the teeth on the starter and flywheel.

if the starter is making grinding sound it not! however it could be loos and needs to be bolted up tight or there may be a bad power joint to the starter,, check for this also check all the earth leads off the engine to the battery, if its still grinding then its likely to be a dud starter you fitted,, the solenoid is not fully engaging the starter bog in the fly wheel teeth and it stopping short and then it spins up this is whats making the grinding noise, it can also make a right mess of your fly wheel ring gear,, so dont leave it to long to get it sorted out,

possibly the ring gear(teeth on the flywheel that the starter meshes to when cranking)remove starter motor,and inspect the teeth through the hole )

most likely your bendex wheel in the starter is not engaging the flywheel this could be due to a bad solenoid on the starter. chances are it's a bad starter, i would check to make sure all connections to starter are tight and you have atleast 11.5 -12.5 volts of current in the battery. low voltage can cause this problem as well