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Auto electrician help needed poor, weak, inconsistent, no spark

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Hi, I've tried searching but I can't find anything, I'm not sure if my search engine doesn't work very well because I'm on a mobile. 

Anyway...my problem is an occasional spark. It probably sparks for one revolution once in about 10 kicks. I'm not sure if it seems to spark for the first time I kick it after it hasn't been sat for a while. 

The bike is a 2012 YZF 450.

I was also wondering if anyone has ever came across a basic general guide to diagnosing electrical issues? Mechanically I know what is going on but I just struggle a little with the electrical side and would love to learn how to diagnose things quickly with a few multimeter tests. 

I've never tested the spark with the tank on and fuel pump connected. Not sure if that would affect anything but the bike won't kick. 

Edited by Be.St.MX
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1. down load a factory service manual from yamaha's website

2. follow the electrical system testing procedures . There are many.

3. remove all harnesses, especially the stator, inspect, clean, and apply diectric grease when re assembling

4. The pick up at the stator can be contaminated with ferrous debris

5. Replace the plug, plug cap and coil

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On 20/08/2017 at 0:12 AM, THE KRAN said:

1. down load a factory service manual from yamaha's website

2. follow the electrical system testing procedures . There are many.

3. remove all harnesses, especially the stator, inspect, clean, and apply diectric grease when re assembling

4. The pick up at the stator can be contaminated with ferrous debris

5. Replace the plug, plug cap and coil

Hey Kran I checked the electrical system as best as I could I think ? I tested the crank position sensor, kill switch and coil but I can't find any other testing for the ignition side of things. I cleaned all the connectors allowed them to dry and applied dielectric grease. Cut the wire for the cap down for a better connection. The coil checked out in spec on the resistance checks. Could it be faulty but showing in range? I've also replaced the plug. The system is getting power as the fuel pump spurts fuel out when I kick the bike with the connector in place but pipe disconnected. 

Are the chances most likely to be on the coil?

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11 hours ago, THE KRAN said:

Stator ? That's where you start your testing, as that's where the current is generated...

I agree. Have you opened up your left side engine cover? On my 2011 yz450f I found the stator to be DE-MAGNETIZED!

If you open up your left side engine cover you should see a flywheel. On that flywheel, a few pieces can dismember themself. 

I myself found my stator to have a few loose magnets and pursued my situation from there

I ended up having to replace my stator and my flywheel. How someone caused this damage on an mx bike I do not know. The manual outlines testing procedures and you should definitely follow them. The most important part is making sure your stator is producing power.....and than from there you can further diagnose (per manuals stats) tracing and diagnosing the issue.

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Sorry it was on the next page so I didn't see the part where it says to test the stator. I tested it and the resistance is supposed to be ohms X 1 on the multimeter so I set it at 200 as mines digital. The tolerance is 0.6-0.9 and it was flickering between 0.8 and 0.9 on my meter. 

I know the magnet is strong as I could feel the magnet pulling the stator in to place when I removed the cover to clean the stator and flywheel. 

I pressed the plug harder against the earth and was getting a better spark. So I think it may have been a poor earth. 

Now I've realised I have an issue somewhere else. The bike will bump but won't kick start. The valves are in spec.

To tick over the idle speed increaser / choke must be pulled out and the tick over wound fully out. I'm thinking it may be the fuel pump that is causing the problem now. I'm going to test the pressure of the pump and if that checks out OK I'll do a leak down test to make sure the valves are sealing well. 

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6 minutes ago, Be.St.MX said:

Sorry it was on the next page so I didn't see the part where it says to test the stator. I tested it and the resistance is supposed to be ohms X 1 on the multimeter so I set it at 200 as mines digital. The tolerance is 0.6-0.9 and it was flickering between 0.8 and 0.9 on my meter. 

I know the magnet is strong as I could feel the magnet pulling the stator in to place when I removed the cover to clean the stator and flywheel. 

I pressed the plug harder against the earth and was getting a better spark. So I think it may have been a poor earth. 

Now I've realised I have an issue somewhere else. The bike will bump but won't kick start. The valves are in spec.

To tick over the idle speed increaser / choke must be pulled out and the tick over wound fully out. I'm thinking it may be the fuel pump that is causing the problem now. I'm going to test the pressure of the pump and if that checks out OK I'll do a leak down test to make sure the valves are sealing well. 

Classic symptom of a leaking intake valve, or in an FI bike, a fuel pump with a clogged filter (which usually starves the pump and ruins it....)

 

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Thanks kran, the valve clearances checked out in tolerance.

I'll check the pump pressure and see what is going on there. The only other thing I'm wondering is if the capacitor could cause a fault like this. Would the capacitor effect the power of the spark? 

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