CB550k1 US Import - UK registration

[Oddjob]

I seem to recall it's a male and female connector on the black wire, that's so you can disconnect the rear brake light power feed and jump the black wire into there. As that's only live when the ignition is on it's an ideal point to take power from.

[Laverdaroo]

Or just take a switched live from one of your spare outputs on the M unit straight to the Hondaman box as a key on power feed. There’s loads of options you can do with the M unit Dave. As we missed each other today, when you get back to it, giz a bell


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[juitz]

Ok so have a new issue!

Changed my circuit so now have 12v supply to the coils as I missed this. Still not getting any spark at the points though, but have new OE ones now that I will install.

However, today playing around and checking the system I am blowing the main fuse again. I'm a bit confused as I can sometimes turn on and start cranking with the starter motor, but I started looking at the alternator and sometimes when I wiggle the green and white wires the fuse blows. This indicates a short to me.

It's just inconsistent that I can turn the ignition on and sometimes be ok, then moving the green / white cable can lead to the fuse blowing.
I've removed the sheathing and can't see any broken connections or insulation.

I do have a second and probably bigger issue that I damaged one of the dowel holes due to a broken bolt so alignment on the coil/rotor/stator is iffy. I had to do this with one dowel.

Should I start with a replacement field coil?
Took some measurements on the bench and got this

Field coil - 4.9ohm between GRN/wht on bench

Stator- continuitu between all 3 phases and 0ohm phase-phase resistance

Update:

Removed the stator so only had the rotor and field coil. Measured continuity between green and white to ground and at no position with the good dowel moving the cover around can I break continuity. Took off the gasket and same thing. No matter where I try and move its always grounded.
Taking off the good dowel and I can find a small position where it's not grounded.

There are signs of wear on the inner and outer part of the rotor but thought "it will be fine" when I put it back together as the field coil and stator looked ok.

So I'm thinking either field coil and rotor are buggered, or worst case and my nightmare is a bent crankshaft?

[Oddjob]

Post a pic of the broken dowel hole, is it in the crankcase or the casing?

Remove the sprocket cover and make sure you haven't rushed any of the wires coming from the alternator against the crankcase, very easy to to this if you're not careful.

[juitz]

Post a pic of the broken dowel hole, is it in the crankcase or the casing?

Remove the sprocket cover and make sure you haven't rushed any of the wires coming from the alternator against the crankcase, very easy to to this if you're not careful.

It's on the crankcase - the one highlighted here. I'll take a pic tomorrow

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No cover reithe as I haven't fitted this on yet as was looking for a replacement chain protector bracket. It does have the original cables but they looked ok. But the cables are now "floating" and off the frame.

The continuity to ground.check I did with the multimeter connected to the green and white wires coming.off the coils and to the battery gnd terminal. So nothing upstream of the circuit to short to ground.

[McCabe-Thiele (Ted)]

Can't imagine how a dowel gets  broken - is the remnant in both halves or just the engine casing?
As it is part of centering the alternator I think it's important to find a fix.

[Bryanj]

To test the field the green and white wires MUST be disconnected from loom or you are connected to griund via the green wire!

[juitz]

I replaced the coil mounting bolts with slightly shorter ones  - shorting issue gone? Still need to do something to fix the damaged dowel hole issue though.

Replaced points with OEM units kindly supplied by Oddjob. points gap now set at 0.4mm and lined up (ish) with F marks using the original condensers. No spark ☹️

Getting 12v at the coil black wires and also feeding the Hondaman unit black wire. Other wires connected correctly.
Anything else I can check? Ignition Coils seem to be ok BUT I refurbished them using the tips / tricks method on this site and I could have quite easily messed this up 😂

[Oddjob]

Isn't the coil feed wire black/white? as in coming from the kill switch?

Disconnect the Hondaman unit until you get it running, don't add things that could be at fault, add them when you find the fault.

Check the yellow and blue wires for continuity, make sure they haven't been broken or trapped. Disconnect them from the coils and the points and see if they leak to earth, they shouldn't do.

After that report back.

[juitz]

Isn't the coil feed wire black/white? as in coming from the kill switch?

Disconnect the Hondaman unit until you get it running, don't add things that could be at fault, add them when you find the fault.

Check the yellow and blue wires for continuity, make sure they haven't been broken or trapped. Disconnect them from the oils and the points and see if they leak to earth, they shouldn't do.

After that report back.

Ok will try without Hondaman unit. But yes, I meant the black/white wires. Will double check continuity and connect points directly to coils yellow and blue wires.

 I'm not feeding the coils black/white wires via the kill switch as I dont have one. I'm feeding 12v from the ignition output from an m.unit blue.

In general terms, trying to follow this https://revivalcycles.com/blogs/technical-articles/mo-unit-wiring-diagram

[Oddjob]

Would that not potentially void your insurance? I can just imagine them saying that a kill switch is a safety device so you can kill the engine in the event it's sitting on top of you after an accident.

[andy120t]

There's a cb550 m-unit wiring diagram on Rupes Rewires - which may or may not be helpful! If the link doesn't work, it's on the 4th page of the 'recent job's section.

https://rupesrewires.com/marks-honda-cb550/

[Laverdaroo]

Not a great diagram for what Dave doing,the revivalone is by far the easiest and simplist to follow.
Dave are you just using the key to stop the engine then?

[juitz]

Not a great diagram for what Dave doing,the revivalone is by far the easiest and simplist to follow.
Dave are you just using the key to stop the engine then?

Apparently, double tap of the start button is supposed to be the "kill" switch of the m-unit. Can't test this though 😉

[Laverdaroo]

Yeah that’s right, sorry I thought you were going kickstart only for some mad reason when I typed that. Even after you asking about solenoid etc!

Sorry, brain fart!

What switches are you using Dave?


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