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Motorbike Capacitor Problem

By on July 7, 2017
bike jerking fix










bike jerking repair

Last couples of day my bike was jerking intermittently and some times it stop to accelerate while opening throttle by accelerator while running. Some times I feel that my bike is running out of the petrol.

One day I was on the way to my workshop with my bike and suddenly the bike got stopped to accelerate so I took the bike on one side of the road and trying to start with the ignition but it fails to start. Assuming lack of petrol so I put the petrol lever on reserve mode and checked whether it gets start or not (but my petrol meter showing enough petrol in the tank) I have doubt of some dust like thing clogging the petrol supply and it still didn’t start.

So I took the bike to the nearby bike mechanic. He checked spark plugs and found ok then checked the petrol flow through the lever by removing the rubber pipe the flow is smooth but he found some dust in the petrol, he suspected carburetor fault. I left the bike for the mechanic to check and he agreed to send it back to me once done cleaning the carburetor.

Mechanic delivered the bike to me after 3 hours; I took the trial and found everything was smooth functioning after 2-3 day the problem again started so I contacted the mechanic; he wants more time to inspect the bike so again I left the bike with him and I got phone from him after some times stating that there was a problem with rectifier and needs to be replaced.

But at nearby area this rectifier is not available and he will arrange in day or two. So I asked him can I use the bike without rectifier till the time; after confirming that I can use the bike without working of the headlight till the battery is charged. So I picked up the bike and collected the rectifier . On arrival to my workshop for curiosity I took the bad rectifier and put it on my workbench for checking.

bike rectifier

The function of the rectifier is used for charging the Battery and supplying the voltage to nos. of parts like head light, Signal light, speedometer light, ignition switch horn and so on. (Getting AC Current from alternator of the bike and converting it in to DC through the help of this rectifier and filter Capacitor). Here is the reference circuit diagram.

bike electronics diagram

On inspection the unit look what I found:

bike capacitor problem

When looked from other side I found both legs were corroded and broken

motorbike capacitor problem

So I decided to replace the capacitor and see whether it works. I have removed the damaged capacitor which showing value 4700uf 25V – 80˚Temp and replaced with 4700uf 35V – 105˚Temp.

motorbike capacitor value 4700uf 25 volt

Insulated the capacitor legs with hot glue gun for protection and now unit is ready for further testing.

how to repair bike jerking

Now I took the bike to my bike mechanic with this repaired unit & asked him to put the unit back and see if it works, so he fitted the unit and started the bike and I have taken trial round. Now it gives smooth acceleration sound and no more jerking. It has been over two weeks and it worked without any problem.

This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.

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Note: You can check his previous repair articles in the link below:




  1. Humberto

    July 7, 2017 at 12:15 pm

    Well done Yogesh, your motorbike is working perfectly 100% now

    • Yogesh Panchal

      July 11, 2017 at 7:49 pm


  2. Parasuraman

    July 7, 2017 at 12:52 pm

    Well done! Automobile mechanics generally do not know much about electrical/electronics!

    • Yogesh Panchal

      July 11, 2017 at 7:55 pm

      They do not willing to invest in good Tools for diagnosis the problem.

  3. James

    July 7, 2017 at 2:36 pm

    Did you charge your mechanic for doing his work? LoL 🙂

    • Yogesh Panchal

      July 11, 2017 at 8:04 pm

      Yes of course!
      we believe in "person must be paid for his work before his sweat dries"

      Because he is giving his valuable time for your problems.

      Thanks for your comment.

  4. Albert van Bemmelen

    July 7, 2017 at 5:12 pm

    Nice job Yogesh. Glad you completely solved your transport problem!

    • Yogesh Panchal

      July 11, 2017 at 8:05 pm

      Thanks Albert.

  5. Anthony

    July 7, 2017 at 5:16 pm

    Interesting repair Yogesh. Thanks for sharing this information here.

    • Yogesh Panchal

      July 11, 2017 at 8:07 pm

      Thanks Anthony.

  6. Mike Zook

    July 7, 2017 at 8:08 pm

    Good job Yogesh, Parasuraman is right, most mechanics don't know much about electronics. Good thing you do.

    • Yogesh Panchal

      July 11, 2017 at 8:08 pm

      Thanks for your comment.

  7. George Persico

    July 8, 2017 at 2:41 am

    Excellent analysis. Shows that electronic parts can be found (and repaired) on motor bikes. I am surprised that an 80degC capacitor was used in such a circuit.

    • Yogesh Panchal

      July 11, 2017 at 8:12 pm

      yes it gets Heat up as you accelerate the vehicle for high pickup.

  8. Liera biomed

    July 9, 2017 at 10:57 am

    nice save your time and money.

    • Yogesh Panchal

      July 11, 2017 at 8:13 pm

      Liera Biomed,
      Thanks for your comment.

  9. Robert Calk

    July 10, 2017 at 9:39 am

    Good job, Yogesh. I'm glad you got your bike running.

  10. Yogesh Panchal

    July 11, 2017 at 8:13 pm

    Thank you sir.

  11. Wilson daido

    September 19, 2021 at 2:44 am

    I diss a gree with you and your mechanic,capacitor and regulator never interfer with ingine running even if you remove both regulator and capacitor the bike will move smoothly my opinion there was a loose connection of power causing the problem,and it can reapeer any time.


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