Efi cutting out at stop street

[xsel777]

My xc500 has been fixed regarding the gearbix oil leak, no major damage thank god.
But....
there is this persistent cutting out when showing down to turn a corner or when stopping at the robot.
The mechanic has run out of ideas.
So I am hoping your combined brain power will come to a viable solution.
Begin......😀

Sent from my Mi Max using Tapatalk

[CROSSBOLT]

You have had so many problems with this model, I have forgotten; have you tried opening the gas cap?

[xsel777]

I will try that when I get it back. I am busy trying to get ideas I can bring to the mechanic so that he can fix it so I can ride it.

Sent from my Mi Max using Tapatalk

[CROSSBOLT]

Good you have not tried it! It may be a long shot but stuck vacuum vent valves have afflicted many scoots of several brands.

[xsel777]

On another scooter  forum in my country, a technical boffin offered these suggestions which I have forward to the workshop.
==========================
This sounds like a horror...but i am sure one can sort it out methodically.

I would try and get a working 2nd hand lambda/o2 sensor and see if that makes a difference.

What bothers me is that it only happens when you slowing down...and the revs slowly drop and the engine dies.

this points to a fuel supply issue.

If you start it from cold...will it idle without dying?
Does it only dies when the engine is hot?
Have you tried a new fuel filter? I know this sounds simple but it could be the cause for the fuel starvation.

If you run at cruising speed....does it run ok? Can you notice any fuel starvation? Does it lack power or jerk at any time?

My approach would be.
1. O2 sensor. try a working 2nd hand one. Check and ensure fuel supply is ok. The fuel pump that is supposed to pressurize the system can also be failing. maybe try a working 2nd hand fuel pump
3. If above checks out and no EFI faults i would check for air leaks.

then again...it could be something as simple as too tight valve gaps....I had that problem a few times in my life. At cold the engine runs and performs well. At operating temp the idle drops way too low and the motor dies. Even had it on my Honda CRV....high km engine...and unless you reset/increase the valve gaps, you can change any of the other parameters on the engine and it wont do diddly squat.

Try riding with a 'happy tappit' engine....valve gap slightly bigger than recommended.

Sent from my Mi Max using Tapatalk

[xsel777]

Update : I got the scoot back yesturday and so far it has not cut out. This issue is what was causing the delay in me getting it back. The machie said he swopped out everything, but still could not sort out the issue. Then he said it was the CVT system that was causing the issue, it was catching and causing the engine to stall at low revs. I looked over those parts, and the clutch springs were good, just grooves on the plates, so I told him since nothing is broken in the CVT just put it back together. He must have done something different because now magically, there appears to be no stalling issue . I am very pleased.


Sent from my Mi Max using Tapatalk

[Stig / Major Tom]

Must have a heck of a "catch" to stall a 500cc engine!
Mechie rates must be very low in your area?
He gets to visit with your scooter so often.
Glad this one seems to be sorted. Your patience is impressive.
Many of us are following your monthly adventures with this Kymco 500 :-)
Stig
 

[xsel777]

Lol Stig. It is useless getting all steamed up. It just eats my gut, and sours any co-operation that could be possible. In any event I did send an email explaining that this should really not be on my account.
As a result, I got out of it, a spare inlet throat (black plastic elbow), and a o2 sensor. Plus free gearbox oil seals, both sides, and they also did not charge for the gearbox gasket. Only labour, and considering how many hours troubleshooting that must have been put in, I got a discount there too, only 3 hours, so all in all, my bank balanced survived this.... 😀

Sent from my Mi Max using Tapatalk