I agree it is a weak cranking.
John
my own experience has shown me that almost all (>
%) of my "no start", "hard start" problems, was electrical in nature.
when i first got my ride, i would never know if it would start when i would go out to ride, or it would get me home if it did start.
i finally got tired of farting with it, and ripped the harness out of it.
i replaced every single connector, socket, gauge, and lights, all of it with quality stuff.
my bike has never failed to start since.
one thing i noticed was, my ride didn't use the frame for ground, all grounds was to a single green wire that ran directly to the battery.
the only exception was the starter ground, and it was connected to the engine by a heavy gauge black wire.
this can be confirmed by looking at the wires on the battery.
you will have a heavy gauge black and a small gauge green.
the same applies to the hot, you will have a heavy gauge red and a small gauge red.
other things i noticed was:
the chinese invariably used green for ground except for the starter circuit, which uses black.
the chinese use striped wires for signal carrying wires, the pulse pickup.
the chinese use red for wires that connect directly to the battery.
the chinese used black for switched DC.
all of the above was consistent throughout my harness, and i fail to believe the chinese would make my harness specifically for my bike.
edit:
BTW, it doesn't take much crud in the starter circuit to reduce the voltage to below that needed to start the engine.
i would inspect the starter circuit thoroughly, starting at the battery.
the idiot proof circuit:
battery to solenoid. (red)
solenoid to starter. (red)
starter to battery. (black)
remove each of these connections in turn and make sure there is NO CRUD on them
use sand paper to get a clean connection surface.
make sure the black is connected directly to one of the starter mounting screws.
mount the starter, then remove one of the mounting screws.
this is the place to connect the black wire, and make sure the surfaces are clean.
then finally back to the battery.
also, make sure the connections are tight.
you aren't torquing down head bolts here, but they need to be tight.
another good thing to have is a volt ohm meter.
doesn't need to be anything fancy, but it does need to be able to measure up to about 200 volts.
it should be able to measure the ohms of your pickup.
it should be able to measure full stator output.
and it should have more that one selectable range.
and you need to know how to use it.
this is the typical reason i do not recommend a chinese ride to anyone if they aren't reasonably mechanically competent.
if you do not have the abilities to work on this stuff then, honestly, you don't need to be working on it.
trust me, mine gave me fits, i got so tired of working on it, i almost didn't go back to get it one day when it quit on me.
but i kept on it, and eventually i'm glad i did.
i wound up with a ride that, even with all stock components *, had no trouble keeping up with 60MPH traffic 2up.
i could have modified it to get at least 80MPH with no engine modifications.
it turned out to be a fine beast, but i practically had to beat it to death to get it to comply.
* the only "non stock" component on my ride was the rollers.
it came with 15 gram rollers and i replaced them with 20 gram rollers.