Honda-SOHC
SOHC.co.uk Forums => CB500/550 => Topic started by: Brian Cairns on August 30, 2023, 09:46:57 AM
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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
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I would put everything back to standard, including points and then start a investigation ;)
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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
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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.
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Ok thanks all and will check and get back to group.
Got a motorcycle spark for this Friday.
Cheers
Brian
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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.
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Hi, Its a new battery but doesn't mean its snookered, will check it out.
Cheers
Brian
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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.
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Thanks....this advice is fantastic. I will check all comments out.
Brian
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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.
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Cheers,
I'll have a look.
Thanks
Brian
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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
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Thanks ,
Auto spark coming today, still have old rec/reg so will get spark to look at it .
Cheers
Brian
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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.
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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.
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I have seen modifications where 15A fuses are put inline with the three stator wires as a prevention. Might help diagnose without burning out another alternator stator.
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15amp way too big per phase, total output of all three not that
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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.
Hi , please excuse my ignorance, do i have to pull the rotor to check if dowels are in place, where are they located?
Thanks
Brian
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Just the cover Brian!
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Brilliant, thank you.
Cheers
Brian
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If you do find the dowels are missing Brian, I have some here. They are No.11 on the fiché
[attachimg=1]
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If you do find the dowels are missing Brian, I have some here. They are No.11 on the fiché
(Attachment Link)
Thanks, will do.
Cheers
Brian
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UPDATE:
I now have bike sorted.
My mechanic ( now ex-mechanic) installed the new regulator/rectifier incorrectly, in fact he did not install the one I gave him at all, he used a rectifier he had in stock but still managed to wire it up incorrectly.
I got an auto spark who sorted it.
I took bike for a 25 mile run and then using an IF temperature gun, I measured the following temps.:
Fins ; 120 oc
Stator/Rotor side casing 72 oc
electronic ignition side casing 68 oc.
This all seems normal.
Bike is running really well, I have to install the spring on the choke rod for the carb yet.
I can get bike easily up to 80 mph but not much there after.
Idle sitting at 1200 rpm.
Thanks for all your help
Brian
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What spring on choke rod?
Should get beyond 80mph quite easily, should really only start to struggle after 100mph.
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UPDATE:
I now have bike sorted.
My mechanic ( now ex-mechanic) installed the new regulator/rectifier incorrectly, in fact he did not install the one I gave him at all, he used a rectifier he had in stock but still managed to wire it up incorrectly.
I got an auto spark who sorted it.
I took bike for a 25 mile run and then using an IF temperature gun, I measured the following temps.:
Fins ; 120 oc
Stator/Rotor side casing 72 oc
electronic ignition side casing 68 oc.
This all seems normal.
Bike is running really well, I have to install the spring on the choke rod for the carb yet.
I can get bike easily up to 80 mph but not much there after.
Idle sitting at 1200 rpm.
Thanks for all your help
Brian
Many cowboys about that think they know what they are doing is correct ;)
Next time you take the bike out rev to 7000 rpm and change gear at those revs and see if it is still sluggish. If you are still struggling to get it past 80 mph, have a look at your float height's to check that you are getting enough fuel.
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Ok Thanks.
There are 2 springs which are on the choke rod linkage in the carb unit. The larger spring opens up 2 carbs and the smaller spring ( which essentially joins the rods) opens up the other 2. The smaller spring was missing. Half choke opens up the 1st 2 carbs the smaller spring ( which essentially joins rods together) open ups the other 2 carbs when on full choke. Previous owner tried to use copper wire as a replacement for the smaller spring, apparently this is a common ‘hack’. Mind you my ex-mechanic might have lost the spring. I persuaded my original and trusted mechanic who i have been using for years to come out of retirement to sort my bike, he told re-done the carbs and synced them , he told be about the missing spring. I was lucky to get one of a motorcycle breaker on ebay. You could never buy the spring separately from Honda and they don’t make the whole linkage at all now.