The stock bike comes with a 45/140 idle jet. Big problem for hot and humid Hong Kong - the scooter ticks over nicely but bogs when opening
the throttle from idle. It is so bad that the scooter is virtually unrideable. To prevent stalling you have to keep the bike revving
like you are about to launch off a start line. Tinkering with the air mix screw does not cure the problem, although making the mixture leaner
certainly helps. It still bogs and stalls at least once on every ride. Solution: change the idle jet to a slightly leaner one: 50/160 or 48/160.
The problem is solved completely. In Hong Kong conditions, 48/160 ticks over better. This is with the stock catalytic converter. The stock main jet stack is 140/BE5/96. The engine runs
very rich with the stock setup. This is the original plug after 1,000km with the idle jet changed to 50/160 but the rest of the setup as stock.
Note on spark plugs
There is conflicting information on the internet about which is the right spark plug for a 2011/2012 PX150.
Many people say it is acceptable to use a non-resistor spark plug like an NGK B7HS, presumably because older model PX150's could use a non-resistor
spark plug. The CDI unit on the 2011, 2012 model is different from the older models. The owners handbook states that a Champion RL82C should
be used. The equivalent NGK resistor plug is a BR6HS or BR7HS. There may be a risk of damage to the CDI Unit if a non-resistor spark plug is used.