Author Topic: Ignition problem  (Read 3720 times)

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Offline 70CB750

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Ignition problem
« on: October 23, 2024, 09:02:03 AM »
I am trying to install electronic ignition.  Not sure of a brand, got it from 4into1. 

I followed instructions to the best of my abilities and it fires up now, but runs on two cylinders only.  Sounds easy enough?  Actually no, only 2nd and 4th cylinder are firing.  Whiskey, Tango, Foxtrot? 

Ideas?  I want to assume the ignition is working properly.
Prokop
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Offline PeWe

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Re: Ignition problem
« Reply #1 on: October 23, 2024, 10:23:06 AM »
A rotor that should sit correct?
Plus wiring to correct coil.
If both are involved ending up like that....
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline bryanj

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Re: Ignition problem
« Reply #2 on: October 23, 2024, 11:01:42 AM »
Is it possible you have the plug leads on the wrong plugs
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline 70CB750

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Re: Ignition problem
« Reply #3 on: October 23, 2024, 11:36:21 AM »
I am sorry, I forgot to mention that this is CB750. 1978 F3 motor.

I tried to swap leads blue to yellow and it did not fire at all. 

The rotor is much like Pamco, it can sit two ways but there is a mark on top of it and instructions say set it towards 1-4F.   I will try the other way later today.'

But why would fire one cylinder per coil only?

Plug leads have different plug sockets: two straight ones for one coil and two bent ones for the other coil. 
Prokop
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I love it when parts come together.

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CB900C

2006 KLR650

Offline PeWe

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Re: Ignition problem
« Reply #4 on: October 23, 2024, 12:14:27 PM »
If rotor is wrong oriented, swapping blue and yellow usually help.

Strange since 1&4  fire at the same time as 2&3 also do.
Coils with leads OK? All the way to plug.
I had issues with a new dyna graphite lead, occasional misfires that got worse. Probably broken inside.

Used copper leads since then. The harder type sit better in Dyna style coils.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline 70CB750

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Re: Ignition problem
« Reply #5 on: October 23, 2024, 01:07:46 PM »
I believe coils and leads are in working order, because I pulled Pamco out - the rotor was stuck on the advancer - and after I took it apart and installed for a test run. the bike ran just fine. 

Unfortunately I killed the Pamco board putting it back permanently  :( - hence the new ignition I need to figure out.
Prokop
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I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline 70CB750

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Re: Ignition problem
« Reply #6 on: October 24, 2024, 07:52:04 AM »
I keep messing with it, drives me crazy.  Pulled a plug, left it on the engine, sparks are flying while cranking.


Now I found out in instructions troubleshooting:

Spark caps are non-resistor types.  The ignition requires that the spark plug caps are 5K resistor caps.

I tried to measure caps resistance but I am getting OL; how do you measure cap resistance? 

Edit: Never mind, senior moment.  I need to take a break  ;D
« Last Edit: October 24, 2024, 07:59:30 AM by 70CB750 »
Prokop
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I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline 70CB750

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Re: Ignition problem
« Reply #7 on: October 28, 2024, 02:37:55 AM »
She is.back on the road.  I figured it out.  The last problem was fuel delivery to carbs from the auxiliary tank. 

I was also able to fix the Pamco plate and save it for future.

The 4into1 ignition allows you to install the advancer with the rotor together.  I like that.

But dealing with ignition while there is a sidecar mounted on is effing challenge.
Prokop
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Pure Gas - find ethanol free gas station near you

I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline HondaMan

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Re: Ignition problem
« Reply #8 on: October 30, 2024, 08:38:21 PM »
But dealing with ignition while there is a sidecar mounted on is effing challenge.

Yeow!
You just reminded me of working on a 750 with the Vetter sidecar ("Terraplane") installed. I'd forgotten that pretzeling exercise.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline bryanj

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Re: Ignition problem
« Reply #9 on: October 31, 2024, 07:58:47 AM »
We are lucky in UK as sidecars go on opposite side!
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline 70CB750

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Re: Ignition problem
« Reply #10 on: October 31, 2024, 11:48:27 AM »
But dealing with ignition while there is a sidecar mounted on is effing challenge.

Yeow!
You just reminded me of working on a 750 with the Vetter sidecar ("Terraplane") installed. I'd forgotten that pretzeling exercise.

Aligning the advancer |F with the case mark was not possible.  I had to transfer the point to the magnet holder and go from there.
Prokop
_______________
Pure Gas - find ethanol free gas station near you

I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline 70CB750

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Re: Ignition problem
« Reply #11 on: October 31, 2024, 11:49:00 AM »
We are lucky in UK as sidecars go on opposite side!

Thank you, Bryan, that makes me feel better  ;D
Prokop
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I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline HondaMan

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Re: Ignition problem
« Reply #12 on: November 05, 2024, 06:15:16 PM »
We are lucky in UK as sidecars go on opposite side!

Did you ever see a Vetter Terraplane there?
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline bryanj

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Re: Ignition problem
« Reply #13 on: November 05, 2024, 06:21:17 PM »
I havent, dont even know if one came here. All the "Hondastyle" accessories, fairings, crashbars etc were made by Rickman.
I used to buy stuff from Paul Dunstall regularly, even had a couple of his show bikes to sell where i worked
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline bryanj

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Re: Ignition problem
« Reply #14 on: November 05, 2024, 06:24:17 PM »
As an aside we had a customer who wanted a Cossack Ural with the posh 350 sidecar and that had to be on the "wrong" side which made it a real pig to ride due to the camber on uk roads
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline 70CB750

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Re: Ignition problem
« Reply #15 on: November 15, 2024, 04:26:12 AM »
As an aside we had a customer who wanted a Cossack Ural with the posh 350 sidecar and that had to be on the "wrong" side which made it a real pig to ride due to the camber on uk roads

There are roads I avoid with the sidecar because of too much camber.  It eats you up fast.
Prokop
_______________
Pure Gas - find ethanol free gas station near you

I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline willbird

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Re: Ignition problem
« Reply #16 on: November 15, 2024, 08:07:57 AM »
We are lucky in UK as sidecars go on opposite side!

That piqued my interest so I googled and found that in the USA I could legally mount one on either side. Was an interesting side note that right hand drive cars are banned in at least one place (Costa Rica). I have never had any interest in a sidecar on a bike.

Bill

Offline Floshenbarnical

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Re: Ignition problem
« Reply #17 on: November 16, 2024, 12:26:35 AM »
We are lucky in UK as sidecars go on opposite side!

That piqued my interest so I googled and found that in the USA I could legally mount one on either side. Was an interesting side note that right hand drive cars are banned in at least one place (Costa Rica). I have never had any interest in a sidecar on a bike.

Bill

May as well buy a trike or a Honda Fit/ Jazz at that point, right
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