Will run but only runs slow like batteries are weak

moved you out of cars, to BMW Motorcycles.
if I leave light (heads/) for 30minutes, (engine running or not)>??????
if engine not running, that is NORMAL
if engine is running that is AbNORMAL and Alt/Gen is dead or fuse blown..
no you have 2 problems?, GEN dead and injection issues.
the cold start fails for these reasons of vast.
1: bad fuel, filters clogged.
2:injectors partially clogged from #1
3: spark weak , plugs bad.
4: or starting it with a DEAD Gen that caused battery to be weak.
but weak batteries do not crank or crank slow. so.... or does barely and now spark is weak with 11v battery weak?

TBO, fix bad gen first so it says running and not flat line the poor battery. I guess you have battery charger and using it to hide the bad GEN sure.

in all cases for sure this , check all fuse for sure all related to GEN.

Are you saying the engine cranks slow? If so the battery could be bad, try to jump it and if that helps change the battery, If it doesn't start the ECM sets "full rich open loop" to start.

Uninstall any previously installed app on your phone
Try uninstalling any battery booster appsor clear your ram

which of 3 engines is it????????
i tried to jump it
jumper cables to a running car?
slow turn over is usually , 3 things.
1: bad battery or its only discharged.
2: spark timing way off, causes engine to try to start backwards.
3: engine seizures. (internal issues) (turn it by hand, ok its good)
4: weak starter. (its bad)

If the unit runs normally after it starts it is probably a defective coil that isnt changing timing relative to crank speed. It is running advanced even at slow speeds and that is the backfire. You could also have a slightly bent flywheel key. This is what sets the primary timing so it is always a good idea to check it when you have the engine cover off!

This problem may be a drain or a bad battery or alternator.

The first thing to do before going on trying to find the system that is draining the battery would be to have the battery tested and charging system tested.

A weak battery will seem ok after the car is jumped or will barely start the car and the alternator will charge it even though the alternator is overworking due to weak battery and during the day or when car does not sit long it will seem ok. then when car sits overnight or a few days battery will weaken on its own, making it look like a drain,

so first step is battery test and alternator/charging system test.

In most cases you would be dealing with a bad stator or voltage regulator. In the case of Suzuki I have found several instances of weak magnets on the flywheel were causing slow discharge of the battery. If you are not running any accessories with memory (radio, clock, etc.), you have replaced your voltage regulator, load tested your battery, and tested your stator for grounding, you may be dealing with a weak magnet in your flywheel. If everything is checking out OK then try replacing your flywheel.

Sounds like you have weak batteries or a bad brake. You can measure the brake resistance at the connector between the front and rear halves of the scooter. The brake is good if the resistance measures between 30 to 65 ohms.
You should load test the batteries to see if they are good. It takes battery power to run the motor and release the brakes. Weak batteries will cause the brakes to drag and the scooter to run slow.
A new brake costs about $70 and new batteries start at $40 each.
If you do not have a beep fault code, nothing has burnt out yet. I would have the scooter checked out soon by a qualified technician. Hope this helps.

If it is more than a year or two old, it is most likely that the battery has become weak and requires replacement. They sell them at Lowes or Home Depot, as well as online.

starter may be weak. usually they crank slow w/hot. i would start there.