Strange : When Radiator Fan running , Engine rev down and shut off

Joined
Dec 2, 2013
Messages
3
Location
Seoul, Republic Of Korea
Bike
04' ST1300
Hello, I'm 06 ST1300 rider In Rep. Korea (South)

1 Week ago, My company colleage bought a ST13.

I checked his ST1300 then showing something strange. So I ask to this forum.

Symptom is :

1. Ignition(Key on) -> engine Start is OK.

2. engine temp rising -> radiator cooling fan runs.

3. when cooling fan runs -> some ticking sound(I think its from Fan motor relay) -> rev drops, and engine off.

Back to the 1, repeated to 3

Bike is not jerk it runs well while engine running.

I compared with my ST, His ST Alternator produced 13.4 volts (Mine was 14.2~3 volt) while idling. but fan starting, It drops 13.1 volts.

I think its alternator was faulty. What do you think??
 

Blrfl

Natural Rider Enhancement
Joined
Aug 24, 2005
Messages
5,689
Age
55
Location
Northern Virginia
Bike
Fast Blue One
STOC #
4837
3. when cooling fan runs -> some ticking sound(I think its from Fan motor relay) -> rev drops, and engine off.
I doubt you'd be able to hear it over the sound of the engine if it were chattering, but it's easy to check. It's behind the left side panel and is the highest and furthest back of the bunch. Just put your finger on it and see if it chatters when you hear the ticking.

The next thing to check would be to make sure the fans aren't binding physically against the shroud or that one of the motors hasn't failed. Either could result in a motor drawing a lot of current and dragging the system voltage down. The connectors for both motors are on either side of the radiator, so you should be able to narrow it down to one side or the other by repeating your experiment with one fan connected.

If the bike is otherwise fine, it's probably not the alternator.

--Mark
 
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