Where is the alternator/generator on xj750 - Yamaha Motorcycles

The problem is either, too lean a fuel mixutre, ign timing module is loose, or damaged plug leads/plugs or the intake is drawing secondary air from a loose / bad gasket in the intake manifold or carb leakage. Also perform a leakdown test to confirm valves are sealing. I assume the valve adjustments have been checked also?

take it to a bike auto electrician for a charging system check
that will include the voltage regulator which may be the problem

you don't, its self adjusting, if it feels slack you prob need a new chain or guides.

Hi have you checked the output from the alternator? This is 3 faze it has 3 yellow wires which connect to the rectifier, here the voltage is converted to dc used for charging the batery, check for broken wires from the alternator under the front sprocket cover, or corroded wires at the rectifier block connector, it is also important to have 12 volts in the battery to activate the charging process, using the machine with a pore condition battery can severley dammage the charging system componants

1. Park vehicle on level ground.
2. Remove battery from vehicle.
3. Remove air cleaner outlet hose, engine under cover ( right side ) and exhaust pipe # 2 .
4. Disconnect " B " terminal wire and coupler from the Alternator ( Generator ) .
5. remove Alternator ( Generator ) belt.
6. Remove Alternator ( Generator ) cover.
7. Remove Alternator ( Generator ) bracket mounting bolts.
8. Remove Alternator ( Generator ).
Installation : Reverse dismounting procedure.
Replace Seal Ring between exhaust pipe # 1 and exhaust pipe # 2.
Torque exhaust bolts to : 43 N-m ( 4.3 kg-m,31.5 lb-ft )
Replace cable straps / defective parts as necessary.
Reinstall battery.