My sunl wont start it has a slow cranking - 2005 Qianjiang QJ150

I think someone is seized to the shaft bearing of the crankshaft.Download the heads and roll the crankshaft clockwise and back to see if pistons move when you turn the shaft or receive clearance and then leave

does it crank fast, at 250 spec RPM?
no year, no joy, all cars have a year,
and and engine option (displacement size???)
my wild guess, is it wont crank or cranks dead slow.
right?
and the battery is DISCHARGED. right,
use jumper start cables. start now?
that be first.

wont crank
cranks perfectly but wont start ?(check for spark, x number of cyl)
spark good, try test fuel
test fuel works for 3seconds and stalls,. then fueling problem , ask.

Might be a bad ignition switch or wiring. May need to check both. Do you have any codes in the ECM ?

i have a 250 and there is a spacer in the gear box right under the starter if the spacer isn't sat right it will make gears bind and nothing will work starter wont turn over at all but if you pull the casing off the left side of motor the starter will spin free. reset the spacer or get a new one

slow cranking with new battery would indicate a weak starter

with the spark plug out and the valve cover removed; place a screwdriver into the spark plug hole; turn the crankshaft until the valves are all the way up and, not moving as the piston just starts to go down in both directions; (use the screwdriver to see this) this is TDC or, top dead center now; you should see symbols on the faces of the cam gear and, the crank gear and, two places on the chain; line up the chain symbols with the gear symbols chain symbols facing out and, install the chain.
by the way they make a kit for stripped sparkplug holes an auto parts store will have it in case you need one again.

is it a clean crank or a lazy slow crank ?
if clean crank check to see if you get a spark or pulse at the injector
slow and lazy crank
double check the timing again
or check to see if you broke or left the crank angle sensor unplug
good luck

sounds like the CDI module. I've had it go out on a couple scoots I've owned. Take it to a shop and have them check it

The Sunl's are notorious for the stator going out. Check with your dealer for specs on testing the stator. It could also be the CDI unit too! I hope this helps