stator overheating

[Brian Cairns]

1978 Cb550 four K3 ( American import)

Hi,
I am a newbie to the forum.

Recently bought the bike above, soon after the stator burnt out, got stator rewound, and it burnt out again.
I managed to find another unused original stator and replaced the regulator and rectifier with a 2 into one reg/rec (bought from David Silver parts). I did not do the work on this bike, an experienced mechanic did.
Also fitted with electronic ignition.

The stator side casing is now running extremely hot, so hot that you cannot touch it for more than a second.
I don't want to ride bike in case I do damage....is the heated casing normal?

Thanks

Brian

[Trigger]

I would put everything back to standard, including points and then start a investigation 

[deltarider]

Some aftermarket rec/reg units simply have the alternator work a full 100% all the time and shunt excess to the frame. Not a good situation imo. OEM REC and REG are well designed and usually outlive a bike. Please specify what electronic ignition you have. Not that that would worry me much. What's the state of your battery? I'm asking because it does not make much sense to comment when battery is partially depleted. You may want to read the charging specifics in the Shop Manual Cb500-550 on p. 94 (bottom): https://www.dropbox.com/s/lirtu1euydi0rol/Honda%20CB500_CB550%20%20Four%20Service%20Manual%20Ammended.pdf?dl=0

[McCabe-Thiele (Ted)]

Assuming you have a good battery I would be checking all the connections for poor contact. Not just at the first block out of the stator.

I am a fan of keeping such things as regulators & rectifiers standard.

[Brian Cairns]

Ok thanks all and will check and get back to group.
Got a motorcycle spark for this Friday.
Cheers

Brian

[McCabe-Thiele (Ted)]

As regards the casing getting hot it is going to be hot with an air cooled engine so I assume you mean super hot.

In my experience (mostly based on cars) many owners continue to use vehicles with a poor battery as long as it starts in the summer relying sometimes on jump starts to get through the next winter. They often then find that when they finally replace the battery the alternator fails shortly afterwards leaving them to think it was the alternator in the first place.
I have found that's false economy as a poor battery will put pressure on the charging system so it's working extra hard at charging to just keep you going.

I regularly check the voltage of the batteries on all my vehicles plus I still use my CTEK to avoid the dreaded sulphation effect. My neighbour thinks I'm mad charging up the battery on my Jeep every six weeks or so in the winter - then he wonders why the battery in his Merc failed after only 4 years.

[Brian Cairns]

Hi, Its a new battery but doesn't mean its snookered, will check it out.

Cheers

Brian

[Oddjob]

I'm wondering if the heat is actually caused by friction. Few reports lately where the rotor casing wasn't fitted with the 2 dowels that locate it properly, this caused the casing to sit a little skew and that caused the rotor itself to start to catch on the stator and the field coils. Any sign of rubbing on those? Also make sure the dowels are in place. If they are missing when you look, unless you know they are meant to be there you'd not know they were missing.

[Brian Cairns]

Thanks....this advice is fantastic. I will check all comments out.


Brian

[gary123]

I'm wondering if the heat is actually caused by friction. Few reports lately where the rotor casing wasn't fitted with the 2 dowels that locate it properly, this caused the casing to sit a little skew and that caused the rotor itself to start to catch on the stator and the field coils. Any sign of rubbing on those? Also make sure the dowels are in place. If they are missing when you look, unless you know they are meant to be there you'd not know they were missing.

This is exactly what happened to mine, you MUST have both dowels fitted.

[Brian Cairns]

Cheers,

I'll have a look.

Thanks

Brian

[AshimotoK0]

This is a good info Honda Bulletin on the early  Honda-4 3-phase charging system. Pretty clever in that it doesn't use slip rings and modulates the magnetism in the rotor, by adjusting the field coil current to suit the charging/power delivery. As said by others, any aftermarket solid-state system, which doesn't replicate that mode of operation is to be avoided IMHO.

Honda's 3-phase charging Service Bulletin.

https://www.dropbox.com/s/2oqrx5cvv7byqao/3-phase%20Honda%20Charging.pdf?dl=0

[Brian Cairns]

Thanks ,

Auto spark coming today, still have old rec/reg so will get spark to look at it .


Cheers

Brian

[Oddjob]

I'd be interested to know your reasoning behind saying that aftermarket solid state combined reg/rec don't do exactly the same job as the old separate reg and rec.

From what I've read the Mosfet type units switch between the 3 modes much faster than the old Honda equipment, there is no chance of a point face burning and sticking for instance, so are more reliable. Manufacturers know exactly how the Honda system works, as the bulletin says it's like other automotive systems employed by other contemporary vehicles and they've been using electronic systems in those for many many years. 

[AshimotoK0]

I'd be interested to know your reasoning behind saying that aftermarket solid state combined reg/rec don't do exactly the same job as the old separate reg and rec.

From what I've read the Mosfet type units switch between the 3 modes much faster than the old Honda equipment, there is no chance of a point face burning and sticking for instance, so are more reliable. Manufacturers know exactly how the Honda system works, as the bulletin says it's like other automotive systems employed by other contemporary vehicles and they've been using electronic systems in those for many many years.

Not sure Ken .. Never owned or used an aftermarket one and not sure how they operate ... always stuck with original electro-mechanical type myself. Comparing the Honda system with automotive alternators of the same era, then they had slip rings and carbon brushes which fed the field current into the field coil ... but yea they would have electronics in them too. I would imagine that the Genuine Honda (Hitachi etc). combined reg/rectifier units, as  used on later bikes,  would replicate the electromechanical system though and hence be OK. It's someone else who suggested that some aftermarket units use 'current dumping' ... as Honda did on the twins with single phase night/day coils on their stators but not really ideal for the 3-phase system models.