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VFR400R starter problem


joe678

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My little NC21 has no problems with a push-start. That works fine.

Pressing the starter button causes normal starter motor operations, but it seems, there is no ignition.

Somewhere (can't find it again...) I read about a ignition/hall sensor next to the starter gear wheel. This sensor causes

the very first ignition impulse!? I am not sure...maybe this sensor is my problem?

(weak battery is not the problem: I connected a big car-battery parallel for testing)

Any ideas?

Thanks

Joe (from Germany)

 

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Hi Joe.

Beautiful VFR400R You Have.

 

You might have an issue with Voltage drop somewhere for a Normal Neutral Start, could be a poor/high resistance connection.

 

- Measure the 12v at the Ignitor Unit.

- What does this voltage drop to as you crank the engine over?

- Compare the voltage reading to the voltage measured at the Battery while cranking the engine over.

How different are the measurements?

 

Note - Keep the Black voltmeter lead on the battery Negative terminal.

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Hi Grum,

thanks for your help! Motor rotation under 4000 rpm was very unclean/ Motor died off...

Just 4 new spark plugs (NGK CR8EHIX-9) solved my main  issue. Motor sounds great again from 1000 up to 12.000 rpm!

I had a great test ride today over 80km.

Start-Switch is still moody. I think the electrical contacts next to my right thumb are just worn out....

But push start works great 😉

Joe

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8 hours ago, joe678 said:

Start-Switch is still moody. I think the electrical contacts next to my right thumb are just worn out....

But push start works great

 

On 9/15/2023 at 12:29 AM, joe678 said:

Pressing the starter button causes normal starter motor operations,

Doesn't make sense that your Starter Switch is "moody" when you say "pressing the switch causes normal Starter Motor operation".

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Yeah it is pretty crazy: First I had problems with powerless and unclean Motor operation under 4000rpm (via push start). Starting via starter switch operated the crank shaft, but somehow "no ignition". After changing the spark plugs there is no reaction on the starter switch at all, but push start leads to a very smooth motor sound at all kinds of rpm.

Freaky bike... Maybe indeed just in this moment the switch button contacts reached the end of their life?

Kill switch is fine: test drive - turn on/off - function is OK.

Thanks for your helping ideas!

Joe

Edit: Just found out the 4 contacts at the starter motor relais (behind the 30A fuse) have 0 Ohms. Seems to be broken. Looking for a new one...let's see...

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On 9/24/2023 at 6:17 PM, joe678 said:

Yeah it is pretty crazy: First I had problems with powerless and unclean Motor operation under 4000rpm (via push start). Starting via starter switch operated the crank shaft, but somehow "no ignition". After changing the spark plugs there is no reaction on the starter switch at all, but push start leads to a very smooth motor sound at all kinds of rpm.

Freaky bike... Maybe indeed just in this moment the switch button contacts reached the end of their life?

Kill switch is fine: test drive - turn on/off - function is OK.

Thanks for your helping ideas!

Joe

Edit: Just found out the 4 contacts at the starter motor relais (behind the 30A fuse) have 0 Ohms. Seems to be broken. Looking for a new one...let's see...

???!!!

Are you working with a wiring diagram of your bike????

 

You've stated twice your Starter Motor is working fine. Now you're saying all four Starter Relay contacts are shorted. If that was the case you'd Blow the Main Fuse instantly or destroy your Clutch Diode, and your Starter would never work?

Doesn't make sense to me!

 

Very easy to test the Starter Switch. With Ignition to On you should measure 12v at the Yellow/Red wire of the Starter Relay Every time you press the Start Switch.

 

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Hi Grum,

testing the starter relais resulted in confusion - maybe some kind of a loose connection? The next day I found out, the cable just behind the connector has a kind of cable break.

Second problem was a dirty fuel filter. Only with a full tank threre was enough presssure in the fuel line to spend enough fuel for the carbs. Below 40% of tank volume I had

the issues with unclean motor operation...

So right now with new spark plugs, a new fuel filter and some typing on the connector cable at the starter relais, my bike runs pretty fine 😉

I am happy again! (and learned a lot)

Thanks for helping!

Joe

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