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A65 ALTERNATOR QUESTION!
#214509 09/19/08 6:48 pm
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Hi Guys,I need some advice concerning Alternator power outputs.My (non standard)1964 A65 Rocket has a 3 wire Alternator,so I assume this is the original 6 volt Lucas RM19.I've converted the system to 12 volt and done away with the rectifier and fitted a voltage regulator(so no need for a zenor diode either),My questions are;
1.what is its wattage power output(can't find it in the BSA workshop manual)
2.what is the next upgrade alternator(I need about 160 watts)
3.As I understand it,its the stator that provides the wattage power!so do I need to replace the rotor aswell.
Anyone with a reasonable priced upgrade answer
Cheers for your help.Paul.


78 TRIUMPH T140v BONNEVILLE
52 TRIUMPH 6T THUNDERBIRD (custom)
64/65 BSA A65 ROCKET (trike)
68 BSA B25 FLEETSTAR
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Re: A65 ALTERNATOR QUESTION!
rebelpaul #214511 09/19/08 7:05 pm
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Guys,I forgot to add,having searched back over previos posts,no one seems to offer an upgrade alternative,for example would the Triumph T140's alternator which is a Lucas RM21 offer a higher wattage and would it fit my A65,And what about usefulness of the SPARX 12 volt 2 wire alternators would they have a 160 watt capability.
Cheers again,Paul.


78 TRIUMPH T140v BONNEVILLE
52 TRIUMPH 6T THUNDERBIRD (custom)
64/65 BSA A65 ROCKET (trike)
68 BSA B25 FLEETSTAR
Re: A65 ALTERNATOR QUESTION!
rebelpaul #214610 09/20/08 3:08 pm
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Hi Paul,

Originally Posted by rebelpaul
no one seems to offer an upgrade alternative,


Not correct - afaik, Lucas alternators are interchangeable as far as physical mountings go. Certainly, if you've identified an RM19 correctly, any later Lucas alternator (RM20, 21, 23 or 24) will fit.

However, that you require 160W+ max. output rules out the RM20 or RM21; both of these have a max. output of 10.5 Amps (Lucas's figures) which is equated (by the mathematically-challenged) to 120W.

Your choices are the 14.5A single-phase RM23 or the 'high-power' (14.5A) version of the 3-phase RM24 (there's also a 10.5A 'low-power' version). 14.5A is generally equated to 180W (by the mathematically-challenged again wink ). If you go for RM23, it's a bolt-on (assuming the existing reg./rect. can take the maximum output). If you go for the RM24, while you'll need a 3-phase reg./rect., you'll get the advantage of much more of the power at lower revs. - Lucas advertised 85% of max. at 2,800rpm, where you'll be lucky to be getting 50% out of any single-phase.

Originally Posted by rebelpaul
what about usefulness of the SPARX 12 volt 2 wire alternators


Apart from the well-known Sparx problem of rotor centre hole clearance not enough to fit British bike cranks, frown the advertised outputs are somewhat dubious. Watts is a bad comparator because it's a product of Amps and Volts - vary either of the latter and you get a different Watts figure. frown Lucas specified alternator outputs in Amps; the commonly-known Wattages (120W and 180W) are actually obtained by multiplying the Amps by 12V (roughly - hence my references to 'the mathematically-challenged' wink ). Sparkx alternators are Far Eastern (Chinese?)-made copies of Lucas alternators but their advertised maximum Wattages appear to be obtained by multiplying the same/Lucas Amps by the maximum voltages reached before the reg./rect. kicks in - just under 14.5V for the 3-phase and just over 15V for the single-phase. shocked

It's a pov but, imho, plays on the relative ignorance of electrics of most Brit. bike owners. mad In operation, Lucas alternators would produce the same higher Wattages if connected to the same reg./rects.; more to the point, at above 12V, all the power users (ignition, lights, etc.) are using increased Wattages, so 'increased' production is both irrelevant and misleading. frown

Hth.

Regards,

Re: A65 ALTERNATOR QUESTION!
Stuart #214641 09/20/08 8:19 pm
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Hi Stuart,Many thanks indeed for coming to my rescue,I lack confidence and knowledge when it comes to interchangeable parts and your explaination is what I was hoping for.Sometimes I can sound a bit "thick" with my questions,I know what I mean but often I don't know how to put it into words.
As for my calculation of 160W,well thats assuming everything is switched on at the same time,when in reality thats hardly going to happen!My single phase voltage regulator is made by Wassel in the UK and has a maximum loading of 160W, so my best bet is to go for a RM21 or the RM23.
Its disappointing to hear that SPARX alternators are suss as their price here is around £50 for a stator, which I can afford.
But I do thankyou for your answer as this does make it clearer to me,Cheers again,Paul.


78 TRIUMPH T140v BONNEVILLE
52 TRIUMPH 6T THUNDERBIRD (custom)
64/65 BSA A65 ROCKET (trike)
68 BSA B25 FLEETSTAR
Re: A65 ALTERNATOR QUESTION!
rebelpaul #214706 09/21/08 10:11 am
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Hi Paul,

Originally Posted by rebelpaul
Many thanks indeed for coming to my rescue,


No worries, glad to be of help. We all have to start somewhere, I just happened to have started faffing about with bike electrics 30-odd years ago. wink

Originally Posted by rebelpaul
As for my calculation of 160W,well thats assuming everything is switched on at the same time,when in reality thats hardly going to happen!


Nothing wrong with that as a rule-of-thumb; :bigt: I try and allow about 10% of alternator output to keep the battery charged, so I can then be reasonably sure things like indicators and horn shouldn't affect the normal running of the bike.

Originally Posted by rebelpaul
My single phase voltage regulator is made by Wassel in the UK and has a maximum loading of 160W, so my best bet is to go for a RM21 or the RM23.


The RM23 has a quoted output of 14.5A, aka 180W.

Originally Posted by rebelpaul
Its disappointing to hear that SPARX alternators are suss as their price here is around £50 for a stator,


Sparkx alternators aren't suss as such, as long as people understand what they're actually getting for their money.

All that said, I'm going to try and pm or e-mail you with some additional information so, if you don't get it, please let me know.

Hth.

Regards,

Re: A65 ALTERNATOR QUESTION!
Stuart #214752 09/21/08 2:42 pm
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Stuart,

While the Sparx rotor fit has been reported, John Healy has given details about the problem, fix, and approximetely when it was an issue. To keep reporting that rotor fit is a problem is just repeating old information that causes more harm than good..... sleep

BTW, I have fit several Sparx alternator's with NO fit problems.....And they do work well, even if Sparx tends to be optimistic in their rating system.....

I am a little mystified about what all is on the bike to require 160W of power. It would be interesting to see a list.....


Never underestimate the human ability to elevate stupid to a whole new level!.
Re: A65 ALTERNATOR QUESTION!
Rich B #214776 09/21/08 4:53 pm
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I have to agree with Rich on this one, we have installed many Sparx stators, rotor etc and in each case have not had a fitment problem and they work well under street and racing conditions. If you like to ride around at rpm under 3000 with the lights on I highly recommend the 3 phase sparx as a solution as it will keep your battery charged even with the lights on at lower rpm such as sustained city riding.
Ed

Re: A65 ALTERNATOR QUESTION!
Rich B #214789 09/21/08 6:09 pm
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Hi Rich,

Originally Posted by Rich B
While the Sparx rotor fit has been reported, John Healy has given details about the problem, fix,


Iirc, the fix suggested by John is to return an offending rotor for rectification; fine if the offending rotor is in the US along with John, but Paul is in GB; it's possible that someone in GB rectifies offending rotors but, afaik, he hasn't made himself widely known. Moreover, while there might no longer be a problem in the US, how do you know this is also the case in GB?

Regards,

Re: A65 ALTERNATOR QUESTION!
Stuart #214806 09/21/08 9:02 pm
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Many thanks guys,there is an old saying here in the UK,"you can wait for a bus for ages and none come then three will turn up at once"
Stuart thanks again,as for the RM23 stator pushing out 180W isn't that at 7000rpm(since your reply I've been doing some swotting up)there's no way I'll be doing that speed!so wouldn't my 160W regulator cope?
Thanks Rich for your comments relating to the SPARX stator,the dealer in the uk is www.tri-corengland.com in Herefordshire.The cost of the RM21(type) stator would be about £53.00($100.00)which I can afford.
As for my 160W output calculation,it adds up like this,full headlight 55w,speedo and pilot lights 7w total,rear lights 25w total and hazard lights 46w total including two warning lights and lastly a 3w handbrake warning light,which gives a total of 131watts not including brakelights of course.Obviously I realise not all will be on at the same time,worse case scenario would be a breakdown at night which would require the pilot light(speedo) and rear lights,hazard lights on and handbrake on giving a total of about 80watts,so I hope the repair can be done quickly!!!
Regards,Paul.


78 TRIUMPH T140v BONNEVILLE
52 TRIUMPH 6T THUNDERBIRD (custom)
64/65 BSA A65 ROCKET (trike)
68 BSA B25 FLEETSTAR
Re: A65 ALTERNATOR QUESTION!
rebelpaul #214808 09/21/08 9:11 pm
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Whoops! Sorry ED v,forgot to thankyou aswell for your comments relating to the SPARX products,I have to say I am now leaning towards a Sparx stator,short of any other solutions,I've got two bike shows/autojumbles to go to during the next two weeks,one is the east of england VMCC show,maybe I can pick up a good s/h stator.....Cheers again,Paul.


78 TRIUMPH T140v BONNEVILLE
52 TRIUMPH 6T THUNDERBIRD (custom)
64/65 BSA A65 ROCKET (trike)
68 BSA B25 FLEETSTAR
Re: A65 ALTERNATOR QUESTION!
rebelpaul #214861 09/22/08 3:58 am
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Hi Paul,

I've sent you a pm through the site, regarding a possible local supplier of Lucas components. Would you let me know if you get it ok?

Originally Posted by rebelpaul
as for the RM23 stator pushing out 180W isn't that at 7000rpm
so wouldn't my 160W regulator cope?


Hmmm, while that's surprising, if it's correct, I'd agree with you. I'll check the sources I have but could you let me know yours?

Originally Posted by rebelpaul
cost of the RM21(type) stator


Except that, in your case, a stator on its own isn't a good idea, ime. Firstly, possible clearance issues fitting a Sparkx stator around a Lucas rotor have been detailed on at least one of the Boards - if you can't get sufficient clearance, you run the risk of burning out the stator; if there's too much clearance, the power output of the stator will be reduced. Secondly, the power output of the a given stator is also directly related to the magnetic strength of the rotor; magnetic strength attenuates with age and any RM19 rotor is very old. wink

Hth.

Regards,

Re: A65 ALTERNATOR QUESTION!
Stuart #214928 09/22/08 7:23 pm
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Hi again Stuart,Many thanks for your PM and I will....
I got my info from the TRI-COR comparison chart,though I may have confused the RM23 output with the 3 phase RM24!!
I found a number on my rotor,its 54212006 and the encapsulated stator's number is 472048 269! does that tell you anything?
Can you tell me what is the clearance required between the rotor and stator.
Cheers Paul.


78 TRIUMPH T140v BONNEVILLE
52 TRIUMPH 6T THUNDERBIRD (custom)
64/65 BSA A65 ROCKET (trike)
68 BSA B25 FLEETSTAR

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