Klx140 weak start with new battery

sawyer759
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3
Joined
4/2/2025
Location
Hertford, NC, USA

Hey everyone

I have a 2021 klx140 that I bought a couple months ago. When I got it the guy told me it would only push start. Since I’ve had it, I’ve put a new one way bearing, battery, starter relay and starter motor on it. After the starter motor we took it to the track.

 Electric start was working when we got there but quit after about 3 hours. Back to the usual condition of sounding like a dead battery. (Barely spinning thee engine followed by a click from the starter relay).  My thought was there’s a problem with the stator and the bike isn’t charging itself. Leave it on the trickle charger overnight and still nothing. It barely spins the engine over.

Now I’m not getting anything at the switch. If I jump the starter relay, or jump the starter itself I get a very weak start. Like spin the motor over once and then just a click from the starter relay. 

What am I missing? I’ve checked all the plug connections. Everything is plugged in and tight. Some corrosion on the ignition coil connection but I wire brushed that and still nothing. 

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40acres
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810
Joined
7/23/2017
Location
Houston, TX, USA
4/3/2025 7:28am

Double check the voltage regulator. Should be on the left side, just behind the frame neck. 

1
sawyer759
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3
Joined
4/2/2025
Location
Hertford, NC, USA
4/3/2025 6:15pm

Thanks for the response! I’ll check that out. I’m also not getting anything from the button for the e start now either. 

minton33
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52
Joined
4/10/2024
Location
Big Clifty, KY, USA
4/5/2025 7:34am
sawyer759 wrote:

Thanks for the response! I’ll check that out. I’m also not getting anything from the button for the e start now either. 

Do you have a jump box? Or jumper cables? The battery may just be too weak to spin it over. 

sawyer759
Posts
3
Joined
4/2/2025
Location
Hertford, NC, USA
4/6/2025 4:08am

Battery is new. Using a jump box makes no difference  

The Shop

ADynes
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276
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5/26/2011
Location
USA
4/6/2025 8:53am Edited Date/Time 4/6/2025 8:53am

You're going to have to get a voltmeter/multimeter and do some testing. A cheap $10 harbor freight or similar will work just fine. Through process of elimination it should show you exactly where the problem is. There should be videos on YouTube showing some basic troubleshooting procedures. A wiring diagram for the bike would help, but not absolutely necessary. Downloadable service manuals can often be purchased online, or sometimes found for free. An issue like this can often be solved, or at least narrowed down, in a couple minutes with a voltmeter

1
BRX-WRX
Posts
234
Joined
4/1/2008
Location
Blue Springs, MO, USA
4/8/2025 11:31pm

Trickle chargers will not charge  a low voltage battery. They only maintain charged battery charge 

1
captmoto
Posts
5874
Joined
4/22/2009
Location
Rancho Cucamonga, CA, USA
4/9/2025 4:57pm

You've got some kind of high load or a short in the starter, sucking the battery down. Try a jump pack going directly to the starter to see how it cranks.

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