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pcx 125 wont start if it is warm
Posted: Tue Jun 19, 2018 3:47 am
by Belavrin
Hello@all,
i hope to find some hints or answers herer because i have no idea what my pcx is doing.
My pcx is a 2015 model and worked perfekt until the end of this winter, i killed the batterie

so i bought a new one and all was fine. SInce 3 weeks my pcx wont start if the machine is hot or was standing 8 hours in the sun. It s trieng to start (you can hear teh copmpression of the cylinder) but it is not coming. So i changed the spark and it worked better for 1 week since yesterday it is the same.
If the PCX is standing over night or not in the heat it starst perfekt but if i drive a bit and go shoping for 5 minutes it wont start any more, if i wait some hours it starts.
I have no idea what this can be, could it be a cocke problem ? i mean that the air fuel mix is wrong whe it is too warm ?
i would appreciate any help.
best regards
Alexander
Re: pcx 125 wont start if it is warm
Posted: Tue Jun 19, 2018 6:25 am
by easyrider
Possibly vapor locking.. Fuel pressure regulator stuck ???
Re: pcx 125 wont start if it is warm
Posted: Tue Jun 19, 2018 8:28 am
by fish
How many miles on your scooter?
How long ago were valves checked - if ever?
Fish
Re: pcx 125 wont start if it is warm
Posted: Tue Jun 19, 2018 4:58 pm
by springer1
Take a ride thats long enough to heat everything up completely. Then try restarting the engine immediately after shutdown - not a few minutes later - immediately after you turn it off.
If it does restart immediately after shutdown - but does not restart after a few minutes later - after baking a bit- then it may be an ignition circuitry issue or a fuel related vapor lock situation or etc - that had time to develop due to the heat buildup in those few minutes of baking without any cooling airflow.
Re: pcx 125 wont start if it is warm
Posted: Sat Jun 24, 2023 10:55 am
by Brandemihl
What did this end up being? I am having the same problem. I get a spark though.
Re: pcx 125 wont start if it is warm
Posted: Sun Jun 25, 2023 9:40 am
by Brandemihl
fish wrote: ↑Tue Jun 19, 2018 8:28 am
How many miles on your scooter?
How long ago were valves checked - if ever?
Fish
I have the same problem. 4K miles on mine. I checked the valves a few weeks ago. Exhaust perfect. The intake were tight, because I didn't have feeler gauge the right size to start. My gauge is .13mm. Max w/ tolerance on bike is .12mm. So I believe the valves are actually in.
Thanks!
Re: pcx 125 wont start if it is warm
Posted: Sat Jul 22, 2023 12:54 pm
by valdemordor
Hello to everyone! Has anyone solved this? It's happened to me twice this summer. Both times I left my pcx outside in the sun for a log period then it didn't start. I thought it was a battery issue but once it cooled down in the shade, the pcx started just fine.
Re: pcx 125 wont start if it is warm
Posted: Tue Oct 22, 2024 7:01 pm
by bertzza
Hi.
I also have this issue on my PCX150 on a warm day where the bike has been sitting in the sun. It has also occurs on a hot day when in the shade so I am confident the issue is a Vapour lock as it sorts itself out once the weather has cooled down.
Has anyone found a fix for this yet?