Author Topic: Trouble with bike  (Read 22170 times)

Offline ozzybud

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Re: Trouble with bike
« Reply #60 on: March 04, 2025, 07:52:15 PM »
How many miles are on this bike?
It could be shot clutch basket rubbers . That makes a terrible racket especially if the bike is not running well or tuned properly.
1976 Z50 YELLOW
1970 CT70 BLUE
1971 CT70H ORANGE
1972 CT70H GREEN
1973 CL200 BLUE
1973 CB350F RED
1975 CB360T RED
1975 CB400F BLUE
1975 CB550 ORANGE
1976 CB750F RED

Offline beardylondon

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Re: Trouble with bike
« Reply #61 on: March 04, 2025, 08:04:48 PM »
Carbs were stripped and cleaned and bike fully set up by a specialist 2.5 years ago, but not many miles since.

Total mileage approx 20k, but it’s an import, so who knows!

How many miles are on this bike?
It could be shot clutch basket rubbers . That makes a terrible racket especially if the bike is not running well or tuned properly.
« Last Edit: March 04, 2025, 08:45:30 PM by beardylondon »
1976 CB550 K2 (USA import)

Offline taysidedragon

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Re: Trouble with bike
« Reply #62 on: March 04, 2025, 09:29:51 PM »
Carbs were stripped and cleaned and bike fully set up by a specialist 2.5 years ago, but not many miles since.

Total mileage approx 20k, but it’s an import, so who knows!

How many miles are on this bike?
It could be shot clutch basket rubbers . That makes a terrible racket especially if the bike is not running well or tuned properly.

Carbs will gum up in one winter without use. 2 and a half years will have caused a lot of problems in the carbs.

Clean the carbs now, the earlier work has been undone through lack of use.
Gareth

1977 CB400F
1965 T100SS

Offline beardylondon

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Re: Trouble with bike
« Reply #63 on: March 18, 2025, 04:18:32 PM »
So it continues, looks like it’s running on 2.

Pipe temperatures as follows, from the left hand side looking down, when sitting on the bike, no.1 @ 154 degrees, no.2 @ 50 degrees, no.3@ 152 degrees and no.4 84 degrees.

Answers on a postcard.
1976 CB550 K2 (USA import)

Offline Johnwebley

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Re: Trouble with bike
« Reply #64 on: March 18, 2025, 04:47:15 PM »
Seems like the slow running circuit in the 2 cold cylinders are not working

In normal settings, no 1-4,and 2-4 are paired with same coils and c/bs

So it seems to rule out electrics

Does fuel come out of all 4 carbs when the drain screws are removed?



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Offline Oddjob

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Re: Trouble with bike
« Reply #65 on: March 18, 2025, 07:57:34 PM »
It sounds like you've mixed up the HT leads. The coil with the blue wire runs 1 and 4, the one with the yellow wire runs 2 and 3. I suspect you've got the left hand coil trying to run 1 and 2 and the right hand 3 and 4. Just get them in the right order and it should at least fire on all 4 cylinders.
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Offline beardylondon

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Re: Trouble with bike
« Reply #66 on: March 18, 2025, 08:23:46 PM »
Thanks both, we will check this out.
1976 CB550 K2 (USA import)

Offline McCabe-Thiele (Ted)

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Re: Trouble with bike
« Reply #67 on: March 18, 2025, 08:25:51 PM »
Been there, done that on my 400, the engine did pop & bang.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline beardylondon

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Re: Trouble with bike
« Reply #68 on: March 18, 2025, 09:24:58 PM »
Just to confirm, that no.1 is on the left, as you sit on the bike and look down?

Is there a wiring diagram someone can post?

It sounds like you've mixed up the HT leads. The coil with the blue wire runs 1 and 4, the one with the yellow wire runs 2 and 3. I suspect you've got the left hand coil trying to run 1 and 2 and the right hand 3 and 4. Just get them in the right order and it should at least fire on all 4 cylinders.
1976 CB550 K2 (USA import)

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Re: Trouble with bike
« Reply #69 on: March 18, 2025, 10:05:28 PM »
Just to confirm, that no.1 is on the left, as you sit on the bike and look down?

Is there a wiring diagram someone can post?

It sounds like you've mixed up the HT leads. The coil with the blue wire runs 1 and 4, the one with the yellow wire runs 2 and 3. I suspect you've got the left hand coil trying to run 1 and 2 and the right hand 3 and 4. Just get them in the right order and it should at least fire on all 4 cylinders.
Yes the No1 is left most when sitting on bike.

As that #1 cylinder is showing decent running the coil supplying it also must be OK. The other  HT lead, from that same coil, MUST go to the far right cylinder which is #4.

That leaves the other coil Independabt with two HT leads ..... which go to the middle two cylinders, doesn't matter which way round.

That will,be correct to run at that.

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Re: Trouble with bike
« Reply #70 on: March 19, 2025, 08:30:59 AM »
Thought to add, for wiring "diagram "  :) looking at the #1:4 points on the ignition plate, note the colour of the wire going out of there into the loom, then go up to the coils, same colour wire is the coil for 1&4 plugs, which are the outer most cylinder locations on the engine.

The other coil, obviously going to the middle two cylinder pair.

It doesn't matter which HT lead from one coil goes were, as long as they are identified as above advice. In other words you can swap 1 with 4 as long as they reach, or 2 with 3 ...... but not otherwise.

Offline McCabe-Thiele (Ted)

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Re: Trouble with bike
« Reply #71 on: March 19, 2025, 09:35:51 AM »
I think this bike has Electronic Ignition reading earlier posts.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline beardylondon

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Re: Trouble with bike
« Reply #72 on: March 19, 2025, 09:39:27 AM »
That’s right Ted, electronic ignition.

I think this bike has Electronic Ignition reading earlier posts.
1976 CB550 K2 (USA import)

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Re: Trouble with bike
« Reply #73 on: March 19, 2025, 09:52:37 AM »
Coil arrangement still the same though.

One coil supplies two HT and will only spark correctly eg 1&4 as paired, with the other coil for 2&3.

If you've anything other than the above combination on HT then it won't run all the cylinders correctly.

In this case that number one cylinder seems correct, the other HT from that coil MUST go to number four cylinder.

That will just leave the other coil to supply the 2&3 cylinders in the middle of the engine.

Offline McCabe-Thiele (Ted)

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Re: Trouble with bike
« Reply #74 on: March 19, 2025, 09:54:58 AM »
I can't see having electronic ignition being involved, as has been said if it's firing on number 1 cylinder then that coil at the other end of the HT lead should also be supplying number 4 cylinder. I believe on production the coil on the left side of the frame supplied cylinders 1 & 4. The corresponding LT wire would be Blue for the left coil.
« Last Edit: March 19, 2025, 09:58:29 AM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

 

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