Kymco 500. 24 Volt startmotor supply. Permanent solution for starting problems.

[Geiren]

Hi, thought I would share my permanent solution on the starting problems with the Kymco 500 engine. Even though there are many posts about starting issues with the Kymco 500, none of them really offer a good long-term solution. I have a Kymco MXU 500, which has roughly the same engine as the Xciting, including the electrical system and starter motor.

The problem with the engine is that it lacks a decompression mechanism, which makes it difficult for the starter motor to turn the engine over fast enough.

What I’ve done is install an extra battery in series to supply the starter motor with 24 volts. This results in a completely different RPM on the starter motor, and the engine never has trouble starting.

Originally, the MXU comes with a battery the size of a YTX20HL-BS, with 310 CCA. I’ve installed two YTX14-BS sized batteries with 170 CCA each. It could probably work with smaller batteries to.

The only issue now is that only the battery connected to the engine’s 12V electrical system gets charged, while the extra battery has to be charged manually with a regular charger from time to time. This could probably be rewired with a DC/DC 12-24v charger, but the system can handle quite a few starts before the voltage drops low enough to risk damaging the battery.

There are some video explaining same solution on KTM bikes:

https://youtu.be/YU_bHsYLf4Y?si=5HzT3jjtgq3CKLhZ

[Ruffus]

Inventive solution.
 Its enough to put a LiFePo4 battery parallel to your starterbattery (which making ever) and keep 12 resp. 13 VDC during the starting period. Needs not to be that big, 10-12 Ah are ample to have a peak.
There are several flaws to be expected from this 24 V supply, one could seriousely demage your electronic unit, if not wired exclusively via the starter solenoid.

[wymple]

I installd a 2nd battery, hardwired parallel, and my problems disappeared.  Completely. No need for the 24 volts.