Author Topic: 400/4 non starter  (Read 625 times)

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Offline Scipioafricanus

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400/4 non starter
« on: January 26, 2020, 04:56:56 am »
Bike ran well last summer. No problems.....
In garage since.
Has power, spark & fuel but WILL NOT  now start.
Any ideas will be v welcome.

Offline allankelly1

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400/4 non starter
« Reply #1 on: January 26, 2020, 05:03:29 am »
Fresh fuel?

Also when you say fuel are the plugs wet with petrol

Best wishes Al


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Offline Scipioafricanus

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Re: 400/4 non starter
« Reply #2 on: January 26, 2020, 05:06:34 am »
Thanks, but yep.
& 650 Domi stablemate with only one cylinder booms into life!

Offline Scipioafricanus

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Re: 400/4 non starter
« Reply #3 on: January 26, 2020, 05:09:23 am »
Al,

Plugs not wet but petrol fumes both from plug hole when checking spark & exhaust pipe when plugs in....

Ray

Offline allankelly1

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Re: 400/4 non starter
« Reply #4 on: January 26, 2020, 05:15:01 am »
I would expect if plenty of fuel and choke on plugs would be wet after a few spin overs and not just fumes


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Offline Scipioafricanus

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Re: 400/4 non starter
« Reply #5 on: January 26, 2020, 06:31:30 am »
..."damp" rather than "wet" ....so a little more than just fumes....

Offline allankelly1

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400/4 non starter
« Reply #6 on: January 26, 2020, 06:42:26 am »
Was tank empty before addling fresh fuel as if it was not, normal unleaded can go “off” and then the ethanol then breaks down to leave a layer of water at the bottom of the tank

This is why tanks can rot out

I alway run all my bikes on Esso super unleaded as it has (the moment) no ethanol in


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« Last Edit: January 26, 2020, 06:44:08 am by allankelly1 »

Offline HondaMan

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Re: 400/4 non starter
« Reply #7 on: January 26, 2020, 09:25:14 am »
Are the sparkplugs black?
What kind of ignition does this 400/4 have (points, I hope?), and are they TEC or Daiichi?
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Offline Scipioafricanus

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Re: 400/4 non starter
« Reply #8 on: February 06, 2020, 01:33:34 pm »
So, to return.....

Fuel now drained & replaced with Esso Super (ethanol free).
Plugs wet.
Careful spark check - only No. 4 cylinder sparking.
Points look fine.

(Can 't  say if TEC or  ND - didn't look).

AND thanks for all the advice so far....

Offline Scipioafricanus

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Re: 400/4 non starter
« Reply #9 on: April 02, 2020, 08:40:22 am »
have given up.
anyone wanna buy it?

(only kidding, but feel like it)

Offline allankelly1

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400/4 non starter
« Reply #10 on: April 02, 2020, 09:09:55 am »
Hi

Just looked at the wiring diagram there are two ignition coils, one for cylinders 1 and 3 and the other for 2 and 4 so if you were getting a spark on  4 you should I think be getting a spark on cylinder 2 as it’s the same coil ?

Also looking at the wiring diagram both ht leads for each coil needs to be connected to the plugs as each end of the secondary winding goes to a plug so if one plug is not connected or you have a bad connection or break down in the HT circuit you won’t get a spark or only a weak spark as then the HT “circuit” is compromised or broken



(On a single cylinder bike or a bike that has one coil per cylinder one side of the secondary winding goes to earth and the other goes to the plug and then earth so creating the circuit )


Also just for info the coils primary windings are one side connected to the points by a blue and yellow wire and the other side of the primary winding goes to the run switch and power to the coil is supplied by this black white wire from the run switch / ignition switch, and if any connection is corroded then like a bad supply from the ignition switch to the run switch or from this switch to the coil or if the the blue and yellow wires connections are bad voltage to the ignition system will be affected by this high resistance

(And as I have just rebuilt my CB400f front end with new switches and other new electrical parts can believe this, as it’s a right “snakes wedding” under the tank where the handlebar loom connects to the main loom)




So if you suspect the ignition system supply is at fault if you connect via a temporary connection the black and white (that connection in the picture to the left of the points that looks like a “Y” direct to the battery “+” so you are bypassing the complete ignition switch so that the coils are constantly “live” and you get a good spark then you will wil then know it’s a fault with the ignition wiring but if you still have no spark the fault most likely is either with the  points, coils, HT leads, plug cap or plugs

I am not a Honda expert but feel free to pm me and I will send you my number if you want some more help


Best wishes and stay safe Al


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« Last Edit: April 02, 2020, 09:56:05 am by allankelly1 »

Offline allankelly1

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Re: 400/4 non starter
« Reply #11 on: April 18, 2020, 09:15:59 am »
Hi any updates

Best wishes Al


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Offline The Lone Builder

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Re: 400/4 non starter
« Reply #12 on: July 28, 2020, 04:22:44 am »
Hi
Just looked at the wiring diagram there are two ignition coils, one for cylinders 1 and 3 and the other for 2 and 4 so if you were getting a spark on  4 you should I think be getting a spark on cylinder 2 as it’s the same coil ?

The right coil supplies cylinders 1 & 4, and the left 2 & 3.
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