KTM 450 SX-F 2009: No Charging after Replacing Stator & Voltage Regulator, AC Voltage 17.8V

Question

Hello. Motor like the topic. No charging. Replaced stator and voltage regulator. Regulators tested in another motor are working properly (charging 14V). AC voltage on connected stator cables (yellow) 17,8V. Battery voltage (motorcycle fired) 11.8V. All cables and grounds checked. What else can...

BANANvanDYK · Answer

White is definitely a CDI power supply (when working without a battery). The battery is definitely functional? 11.8V indicates its discharge, in which case the voltage will not rise quickly to 14.4V. Measure the charging current by plugging an ammeter into the red wire of the regulator.

badyl00 · Answer

This motorcycle does not work without a battery because there is no excavator. Replaceable battery and the same. Current at idle 0.7A, higher at 1.2A

BANANvanDYK · Answer

Can you write what was the reason for replacing parts that were damaged? Does the replaced stator have the same number of coils as the original? Because if different, then the matter is obvious.
I would suggest doing a load test for the alternator itself. Two methods. The first is output short circuit and current measurement (preferably with a clamp meter). The second is connecting about 100W in 12V bulbs to the alternator output and watching if the bulbs will shine with the right power.

E8600 · Answer

What type of battery? Acidic? Has the motorcycle / been abused in the field? I am asking because it is a kross and acid batteries do not like other items, so if it is replaced, only choose gel. If the acid is to check the level of electrolyte and under the rectifier, but not much.

badyl00 · Answer

Parts replaced due to lack of charging. Stator is identical. It cannot be checked for short circuits because after unbinding the cables the motorcycle goes out.

BANANvanDYK · Answer

So, as I thought, CDI power on an additional wire from the regulator. Check the voltage on it, alternating or rectified, regulated 12V or unregulated or high voltage. Also measure the current consumption of the module on this cable by connecting in series with an ammeter. This way we will check whether the module accidentally gets all the power from the alternator.

badyl00 · Answer

1.6 mA DC current consumption on the white wire from the regulator, regardless of RPM. Voltage from 18mV to 40mV at revs. The motor goes out after disconnecting this cable. On the yellow wire measured with clamp meter 1.2A on idle, 4A on the highest. Power consumption in red and white 230mA to 400mA at revs. After disconnecting the battery, the motorcycle continues to operate. The voltage is 5-6V and drops after turning up the revolutions.

BANANvanDYK · Answer

It is interesting. Neither DC nor AC current on this cable? Maybe impulses with e.g. engine speed (though that would be stupid)? Maybe all you need to do is give ground to the CDI input for ignition to work?
One more thing. According to the instructions, the alternator has a power of just 42W. The current on the alternator's phase conductors would be correct, while the battery charging current will not be too high, but of what you give is half the amount.

badyl00 · Answer

Of course, these values are measured with the battery disconnected. The red-white wire is the CDI power supply and the consumption measured on it. The ignition coil is also powered from CDI.

BANANvanDYK · Answer

In fact, measurements without a battery are not objective.
I can't be sure of the alternator, so I request a thorough check. The 2009 model from what I see is more unusual because there are alternators for models up to 2008 and models since 2010 (both are different). Did you buy a motorcycle with such damage or just appeared? Are you sure that there are / were original parts from this model?

badyl00 · Answer

100% parts for this model.

BANANvanDYK · Answer

Try to connect the load in the form of a 35W light bulb with 5W between the yellow stator wires, with the regulator and the battery connected. Theoretically, they should light up with full brightness when the alternator and regulator are working, although the battery and regulator may limit the voltage, and therefore the brightness of the bulbs. Then connect only a 5W light bulb and check if it is lit with the same brightness, which would indicate that the regulator is working.

arek6100 · Answer

Probably there is no chance to find out the answer here, but I have the same problem, so I will ask if it was solved and what was the reason?

KTM 450 SX-F 2009: No Charging after Replacing Stator & Voltage Regulator, AC Voltage 17.8V

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