My Honda VTX stalled at about 60 mph. I thought

low power, does it misfire or acts like dragging a 5000 lb dead weight?
moved you out of cars to MC
bad gas
bad fuel flow, filters"
clogged, injectors
fix fuel flow problems.
only cold hints that EFI can't do COLD enrich mode
due to bad ECT sensors, coolant ? sensor temp coolant
find a way to scan it, not sure how, but some can be.

CHECK YOUR AIR FILTER IT SOUNDS LIKE ITS TOTALLY DIRTY ALSO HAVE YOUR GAS FILTER CHANGED IT MITE BE CLOGGED NOT ALLOWING GAS TO GET TO THE INJECTORS ALSO YOU FUEL PUMP MITE BE ON ITS WAY OUT

hi can you have it scan for a dtc code to know what the problem is or you can buy a diy scanner to do it your self

your battery may not be fully charged yet with the quick jump. let it run for a bit with no lights or accesories, no a\c or heat. everything is run off the computer and it need to be fully charged.

Your fuel petcock is in the rear of the tank. At steep downhill angles all the fuel flows to the front of the tank and not in the petcock. Meaning at steep downhill angles with low fuel level . . .your bike doesn't get any fuel.

there is an aftermarket product called the speedohealer that can help you with your problem. pretty simple to install yourself.

ever drain your carbs ? should be done seasonally . fuel filter problem, sounds like it is running out of gas.

Electrical ... check points. You jmight want to run some carb cleaner through it ... change the plugs. Id look at the points or what ever turns the coil on and off, real close.

I would recommend vtxoa.com. All info is speciffically about the VTX and people are quick to respond to problems.

If your bike is still under warranty take it to a professional.

there are too many reasons...

it could be fuel pump,, it could be ignition coil overheating, it could be the computer itself...

you need two things for the engine to run,

1 is gas
2nd is ignition,,

with these two misfiring or your loosing one of them, it will stall...

i hope i was able to give you some thoughts....

drcool