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Wiring diagram for BSA A50/65 racing bike ? #517210
12/03/13 4:34 am
12/03/13 4:34 am
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steevg Offline OP
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Hi guys,

I've been asked to wire a BSA A50/65 (bits from both) from scratch for a friend. I wonder if anyone can help with a few suggestions for a wiring diagram (or two), and cable sizes etc. He's got the coil wiring to the plugs, but that's about it.

He wants to use it for racing, so doesn't need a great deal fitted:

Points
2 coils
Ignition Switch
Kill switch
Battery (disconnected after every race)
Fuse (size?)
and a Rev counter (no idea which one yet).

Any help or advice greatly appreciated.

Thanks in advance.


Last edited by steevg; 12/03/13 4:40 am.
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Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517216
12/03/13 5:45 am
12/03/13 5:45 am
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Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517218
12/03/13 6:01 am
12/03/13 6:01 am
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Rotherham - S. Yorkshire
Allan Gill Offline

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What switch gear is he using? To have a kill switch on points ignition AFAICS you need a button which you can press to break the ignition circuit. If your friend has Boyer or Pazon, a press to earth type kill switch can be used.

I use 16.5 amp thin wall cable on my looms, its really thin, flexible and has supported a 100w headlight bulb. You could use something which can carry fewer max amps but you may find it too small to work with.

Rev counter: I would stick with the mechanical unit, thats one less drain on the battery.

wiring would be dependant if you go for the EI or not.

otherwise, a feed to the kill switch, from kill switch to coil, coil+ to second coil+ (or - to - depending on if you go + or - earth) the other terminals on the coil connect to the condenser and contact breaker. Condenser MUST have a good earth. Then run a double wire from the other side of the battery to a point on the engine (which will make earth)

I wouldn't bother with an ignition switch. I would use a 7.5-10 amp fuse (I doubt a fuse would be required, as your only making a discharge and chance of a short should be minimal). Removing the fuse when your NOT running the bike would make for an ignition switch.

If using an EI, it would stop drawing any current as soon as the engine isn't turning over, but I would keep the fuse.

2c


beerchug
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517219
12/03/13 6:27 am
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steevg Offline OP
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Larry,
Thanks for the diagrams, I've got something a little more basic drawn up, they're definitely overkill for what I need, but provide some valuable info - thanks.

Allan,
OK, I'm kind of understanding - answers to your questions:

1. No switch gear at present, I think he'll just go for a "break" type of kill switch which interrupts the coil feed.
2. No headlight, so I guess if I'm fitting a 7.5A fuse I'll work to that rating throughout.
3. Rev counter - yes good idea, that'll be one less problem to worry about - providing he can find a mechanical one here in NZ!
4. Negative earth on this one


Questions:-

5. Is the coil permanently powered when the bike's running? I'm expecting it would be otherwise how does it stay energised?
6. This bike has 2 coils - so I'm presuming it has 2 sets of points, and each coil feeds one set of points?

No regulator, no electronic ignition - just a very very basic setup, with a kill switch - will the diagram below work?



Thanks for the input - very helpful.

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517228
12/03/13 10:12 am
12/03/13 10:12 am
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Rotherham - S. Yorkshire
Allan Gill Offline

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Diagram spot on!

Stuart is a good one to ask about coil Amp usage, but from reading another thread, I am pretty sure he said a single 12v coil draws 3amps (2 would be 6 amps) thats the only component in the system that is drawing power.


beerchug
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517233
12/03/13 10:35 am
12/03/13 10:35 am
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kurt fischer Offline

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... and connect all the "grounds" to a "single point" to create a "single point ground" ("SPG") rather than relying on the frame to complete the circuit.

Good info here:
http://www.gabma.us/elec/proper_grounding.pdf


Last edited by kurt fischer; 12/03/13 10:36 am.

Kurt
1968-70-71 Triumph TR6R Bitsa - 1969 Triumph TR6R - 1971 BSA A65L - 1973 Triumph TR5T
2005 Ducati MTS 1000S DS - 2012 Ducati Hyper 796 - 2014 Kawasaki ZX1000
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517279
12/03/13 4:15 pm
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steevg Offline OP
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Allan,
Great, and thanks for the confirmation on the wiring diagram - pretty simple but I wasn't sure about all the rectifiers, diodes's, and other electronic gadgetry which I keep seeing in other information. I'm presuming Stuart is the electrical techie on these forums? Might look him up and send a PM to make sure I'm not leaving anything important out.

But as long as the idea works, I think that's all the guy needs for now!

Kurt,
That's a very interesting article, I take some time to read through it before making a start on the bike next week! I've had grounding problems with bikes and cars previously (as Im sure we all have), so I know how important it is to make sure it's all good and the continuity is low resistance - the idea of bringing all the grounds back to one point is something I hadn't yet considered, but it makes a lot of sense - thanks!

Cheers . . . . I'll let you know how it goes.

Steve

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517285
12/03/13 5:02 pm
12/03/13 5:02 pm
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Stuart Offline
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Hi Steve,

Originally Posted By: steevg
I'm presuming Stuart is the electrical techie on these forums?
send a PM

laughing Thanks for the vote of confidence but "techie" is stretching the point to breaking, I consider myself no better than "in the realm of the blind, the one-eyed man is king". smile Also, I appear to have a bit more time to write than others at least equally-experienced. And my pm box is permanently over the limit. whistle

Originally Posted By: steevg
a "break" type of kill switch which interrupts the coil feed.

+1. A particular type of ignition doesn't need a particular type of switch and vice-versa - e.g. the T160 and '75/'76-on Co-op twins had the Lucas original of this switch cluster to cut the power to coils and points; people have been connecting e.i. to the switch pretty much since the bikes were new.

From a racing pov, unless something like a lanyard kill switch is required, this could be ideal - big red on/off switch, close to the rider's thumb if an AMAL slide jams wot ... whistle Moreover, when it's switched off, there isn't any power between battery and ignition, whatever the ignition is. Otoh, a push-button is on unless someone's physically pressing the button, and anyone not familiar with bike (e.g. a marshal) has to work out that he or she has to press and hold a small black button to turn the engine off ...

Originally Posted By: steevg
if I'm fitting a 7.5A fuse I'll work to that rating throughout.

Ime a bit low - e.g. when I was doing my first rewire, John Carpenter of Mistral Engineering in GB advised a 10A fuse for the Rita e.i., even though the series-connected coils normally draw between 3A and 4A.

I'd also advise using the common automotive 'blade' fuse/holder, rather than the common-on-Britbikes cylindrical glass type.

Originally Posted By: steevg
Negative earth

I really wouldn't get into this. Battery/DC electrical circuits have two conductors; essentially, the electrons travel from battery -ve to the resistance (just the coils on this bike) then from the resistance to battery +ve. Physically, the points and plugs make their circuits through their mounting on the engine, so you need one of the aforementioned conductors to run from the engine to one of the battery terminals; don't use the frame or other cycle parts.

Originally Posted By: kurt fischer
... and connect all the "grounds" to a "single point" to create a "single point ground" ("SPG") rather than relying on the frame to complete the circuit.

Mmmm ... realistically, the bike should have one cable from the engine and another from the coils and condensors, to one or other of the battery terminals (-ve on the diagram). Imho, is there really any point complicating that here with concepts like SPG?

Originally Posted By: steevg
Is the coil permanently powered when the bike's running?

The coils in the circuit you've drawn have nothing electrical to do with the engine. They're in circuit with the battery, so all the time there's a complete circuit from battery -ve through a coil to battery +ve, it's energised. If you want 'em not to be energised any time, you break the circuit with a switch - e.g. the kill switch. smile

Originally Posted By: steevg
This bike has 2 coils - so I'm presuming it has 2 sets of points, and each coil feeds one set of points?

Correct. A pair of points breaks the circuit through the LT windings of its connected coil; that causes the associated magnetic field charging the HT windings to collapse, giving the HT spark. The points are mounted on an auto-advance unit that's spun (on a BSA) by the camshaft; the faster the aau's spun, centripetal force moves its spring-damped bobweights to move the points to advance the spark timing.

Originally Posted By: steevg
no electronic ignition

Be advised that the quality of available points is ... uh ... questionable ... Also, no new aau or parts have been made for a very, very long time, For racing, your friend might be happier with e.i.

Originally Posted By: Allan Gill
I use 16.5 amp thin wall cable on my looms,

For this particular application, I'd probably agree.

But an apparently-arcane digression ...

. "16.5 amp thin wall" is also designated '32/0.2' (32 strands, each 0.2mm) and '1 sq.mm.' being the conductor cross-section area.

. There is also another cable that also has a '1 sq.mm.' cross-section area but is designated '14/0.3', with a 'normal' PVC insulation and only rated for 8.75A.

. Many years ago, I was asked to rewire a T160, for which the owner had bought all-thinwall cable; I had the devil's own job getting, say, crimp-on bullet terminals - that I used regularly on 14/0.3 cables - to stay on the 'thinwall'. frown

So the only advice I'd add to Allan's recommendation is, whatever you choose, check your chosen terminals work with your chosen cable ... you don't want things that start to come loose under the insulation half-way through the racing season ... frown

Originally Posted By: Allan Gill
coil Amp usage, but from reading another thread, I am pretty sure he said a single 12v coil draws 3amps (2 would be 6 amps) thats the only component in the system that is drawing power.

In that other thread, one contributor was advising connecting two 12V coils in parallel to an e.i. with a single output; in that case, you would see a total current draw made up of all the individual coils' current draws, so between 6A and 8A for two 12V Lucas coils. eek That's why e.i. makers advise series connection of multiple coils (in that case two 6V coils).

Otoh, with points, because each coil has its own set, and they're open/closed at different times, the current draw rarely reaches the full 6A-to-8A. bigt

Hth.

Regards,

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517299
12/03/13 6:48 pm
12/03/13 6:48 pm
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Arlington, Massachusetts, USA
kurt fischer Offline

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You're welcome, Steve. What I said is hardly original, it's a staple on this forum. SPG has been useful on all my bikes, (although I wouldn't call it a "concept" Stuart wink but merely a description).

Here's pic of my Bitsa 650 showing a big fat on/off switch for the ignition, useful on street bikes, too. To complicate matters, I run a relay for this switch so that the juice doesn't run through the switch. Back in '71 we had a customer's '71 650 that died, no ignition, turned out that he always used the kill switch to turn off the motor every time which fried the switch. Same thing showed up recently on a Ducati forum.


Last edited by kurt fischer; 12/03/13 7:45 pm.

Kurt
1968-70-71 Triumph TR6R Bitsa - 1969 Triumph TR6R - 1971 BSA A65L - 1973 Triumph TR5T
2005 Ducati MTS 1000S DS - 2012 Ducati Hyper 796 - 2014 Kawasaki ZX1000
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517312
12/03/13 7:49 pm
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steevg Offline OP
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Guys,

Thanks so much for all the info, and Stuart also to you for the breakdown information on the individual parts etc.

For my own info I'd like to clarify:

Firstly, is the original A50/65 a 12v or 6v DC system?

Secondly: If the coils are 6v, and he's using a 12v battery, I'm presuming that I'd wire them in series, and then the points would be paralleled from the output of the "last" coil in the circuit?

If that's makes sense?

Also, in the same circumstances (12v Battery), are there any issues with 12v feeding the points - ie: are the condensers on this bike rated at 6v - & if so, would they fail under a 12 v system?

Thanks, I need to get to the bike soon to clarify a few things - coil voltages, which points, does he want EI in the future etc.!

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517338
12/04/13 12:56 am
12/04/13 12:56 am
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Stuart Offline
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Hi Steve,

Originally Posted By: steevg
is the original A50/65 a 12v or 6v DC system?

Depends; early are 6V, late are 12V - BSA/Lucas changed to 12V in the mid-1960's. 12V is better. As you're building the electrics, and your diagram doesn't show any charging from an engine-driven alternator, put in a 12V battery and go from there. bigt

Originally Posted By: steevg
If the coils are 6v, and he's using a 12v battery, I'm presuming that I'd wire them in series, and then the points would be paralleled from the output of the "last" coil in the circuit?

In theory, it's possible. But you'd have to work out a way of insulating the first set of points from the baseplate. frown

This is (going to be?) a racer. So KISS. smile Either 6V coils in series switched by an e.i. and do away with points, aau, condensers, etc. Or 12V coils in parallel switched by points, with aau, condensers, etc. Anything else is technical willy-waving. grin

Originally Posted By: steevg
are there any issues with 12v feeding the points

Aiui, the main issue you and/or the owner is going to have with points is the quality of modern ones. Apart from that, all the makers passed 12V through the points when they changed their bikes from 6V to 12V electrics. Coils connected in parallel always draw in the 3A-to-4A range, the LT resistance of a '6V' coil is half that of a '12V' coil.

The relationship between Volts, Amps and resistance (Ohms) is Ohm's Law - E=IR or Volts = Amps x Ohms - put in any two values and get out the third one. bigt

Originally Posted By: steevg
are the condensers on this bike rated at 6v

Never use condensers you don't know. A 12V condenser is a 12V condenser is a 12V condenser; brand-new ones intended for a car sourced locally by either you or the bike's owner are the reliable starting point.

Hth.

Regards,

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517352
12/04/13 6:07 am
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steevg Offline OP
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All understood! Thanks again

I'm taking a more in depth look tomorrow, so may have a few more questions, but generally I think I'm there with what to do and what to expect.

Cheers guys.
Steve

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517429
12/04/13 8:09 pm
12/04/13 8:09 pm
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quinten Offline
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check out these Anderson powerpole connectors , they are handy for quickly
disconnecting batteries from a bikes circuit and or hooking up a charger in a total loss system ... or a float charger
on a street bike

http://www.powerwerx.com/anderson-powerpoles/powerpole-sets/

the 15/30/45 amp connectors share the same housing and silver plated contact area , all rated at 45 amps ... its just the crimp-to barrel-side
of the 15 and 30 amp is sized for smaller gauge wires
the housings are reusable , just like a Lego-block and the silver plated contacts are replaceable @ around .40 cents or so
mix and match , fun for the whole family

there are no male or female contacts and a 15A will connect to a a 45A ...

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517441
12/04/13 9:05 pm
12/04/13 9:05 pm
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Pete R - R.I.P. Offline
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I wouldn't use the pre-'67 AAU with only 86 degrees dwell angle,because of the risk of melting pistons.
If you use points,use the later 6CA AAU with 160 degrees dwell angle.A 6CA or 10CA breaker plate will make points adjustment and timing easier.

Any stator can give you 12V.With the early 3 wire single phase stator,you have a choice of running 1/3,2/3 or 100% of the stator output.1/3 may be enough if you're not using any lights.
A low output alternator takes less energy and power from the crank.It may only be 1/10 of a horsepower,but it's something.

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517474
12/05/13 1:29 am
12/05/13 1:29 am
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steevg Offline OP
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Hi again guys,

Thanks for the continued info and I'll forward it all the the owner of the bike. I'm not sure if he's aware of these forums . . . . but he should be!

Huge amount of information here, I'm sure he'll be very appreciative as I believe it's his first BSA.

Cheers,
Steve

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: Pete R - R.I.P.] #517490
12/05/13 6:38 am
12/05/13 6:38 am
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Stuart Offline
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Hi Pete,

Originally Posted By: Pete R
Any stator can give you 12V.With the early 3 wire single phase stator,you have a choice of running 1/3,2/3 or 100% of the stator output.1/3 may be enough if you're not using any lights.
A low output alternator takes less energy and power from the crank.It may only be 1/10 of a horsepower,but it's something.

Uh-uh. Lucas alternators are permanent magnet; essentially, you wave a magnet near a piece of metal, you induce electron movement. So electricity is being 'generated' in all stator coils; whether you provide other components to tap the potential is something separate.

As Steve's talking about a bike intended for racing and he didn't draw any charging circuit in his diagram, I assumed he was going for total-loss so didn't bring up the subject earlier.

Hth.

Regards,

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517499
12/05/13 8:42 am
12/05/13 8:42 am
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Arlington, Massachusetts, USA
kurt fischer Offline

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Steve, what kind of battery are you planning on? I use dry LI batteries in two of my bikes, a Ballistic in one and a Shorai in another. Some people seem to think that the LI batteries will catch fire. Mine haven't so far. I prefer them to lead-acid any day.


Kurt
1968-70-71 Triumph TR6R Bitsa - 1969 Triumph TR6R - 1971 BSA A65L - 1973 Triumph TR5T
2005 Ducati MTS 1000S DS - 2012 Ducati Hyper 796 - 2014 Kawasaki ZX1000
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: Stuart] #517511
12/05/13 9:47 am
12/05/13 9:47 am
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Pete R - R.I.P. Offline
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Originally Posted By: Stuart
Uh-uh. Lucas alternators are permanent magnet; essentially, you wave a magnet near a piece of metal, you induce electron movement. So electricity is being 'generated' in all stator coils; whether you provide other components to tap the potential is something separate.

Until you connect a load to the output wires,you're only making voltage in the unused coils.No power is consumed from them.If they were connected to the rectifier and zener,power is consumed at the zener.That power must come from somewhere to drive the alternator.
Turn a magneto with the points permanently open.See how much harder it is to turn when you allow the points to close at the right time.

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #517932
12/08/13 3:56 pm
12/08/13 3:56 pm
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steevg Offline OP
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Kurt, no idea what battery he's using, I'm just on my way now to find out all about it and start the wiring.

Stuart, you're correct, no charging or starting circuitry in this one, he's just going to push start it, and then charge the battery after every race - simple stuff.

Cheers
Steve

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: Allan Gill] #518097
12/09/13 6:58 pm
12/09/13 6:58 pm
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Originally Posted By: Allan Gill
If your friend has Boyer or Pazon, a press to earth type kill switch can be used.

ONLY if wired negative return!
The only safe way to use a 'grounding' kill switch with positive return is to put it in the trigger circuit.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
72 T150V yet to be named
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: Pete R - R.I.P.] #518099
12/09/13 7:17 pm
12/09/13 7:17 pm
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Originally Posted By: Pete R

A low output alternator takes less energy and power from the crank.It may only be 1/10 of a horsepower,but it's something.

Where do we get this crap?
The alternator produces what it produces. If that energy is not used for work it is turned into heat by the regulator. The energy required to spin the rotor remains the same.
The slight bit of counter EMF developed by the current in the stator is just that, extremely slight in comparison to the power developed by the engine.
1/10 HP = 74.6 W, not likely!


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
72 T150V yet to be named
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #518131
12/09/13 10:55 pm
12/09/13 10:55 pm
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Update:

Hi again guys . . .
I wired the bike yesterday and it looks good.
I had to modify the wiring a bit due to the kill switch wiring not being big enough to take the current for the whole circuit - which seems to be a bit crazy, as I'd have expected a "Kill" switch to do just that - kill the "whole" electric circuitry from the fuse onwards, and not just cut out the engine, but I guess even a Kill Switch can fail "closed", as can relay contacts or indeed any mechanical component - so now it looks like this:



Kurt, I decided the idea of using one grounding point was a good idea, and so took your advice - thanks!

The main wiring was done in 10A wire, and the ground wiring to the points was heavier - 15A rating just to make sure of a good earth.

Any joints were soldered to lessen the chance of future connector problems (my soldering skills are pretty darned good even if I say so myself), and I was asked to fit a method of quick release connectors onto the battery terminals. I chose blue bullet connectors, which seem to work well.

All cables are sleeved to prevent chafing, and the relay is rated at 30A so should be plenty big enough for the job.

I've asked Mike (the owner) to upload some pictures to this post, so hopefully he'll be doing that once he's joined the forums.

Thanks again for the help guys,very impressed with the friendly nature here, and almost tempted to get myself a BSA - though my 2003 Sprint ST was really my idea of good fun (had to sell it a couple of years ago)!

Thanks again, and I'll pop back to see if there's any updates.

Cheers,
Steve

Last edited by steevg; 12/09/13 11:06 pm.
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #518156
12/10/13 5:57 am
12/10/13 5:57 am
Joined: May 2013
Posts: 5,004
Rotherham - S. Yorkshire
Allan Gill Offline

BritBike Forum member
Allan Gill  Offline

BritBike Forum member

Joined: May 2013
Posts: 5,004
Rotherham - S. Yorkshire
Steve, where are you from? UK?

If you get 10amp cable in normal pvc grade, it will be heavier than the thinwall.

If you get 16.5 amp thin wall cable it will be much thinner and more flexible, and 16.5 amp is the minimum you want to get as anything else is too small.

The blue bullet connectors can work well but I suggest using the proper ratchet tool, and heat using heat shrink tubing around the terminal afterwards (John Healy has kindly done an article but I can't find it on the web at present). It gives more support to the connection and helps to prevent stretching.

try these guys for your components http://www.autoelectricsupplies.co.uk/

I get all my bullet connectors from there and use the type in the link. Although depending on application, this might be a better idea.

I am curious though why you need a relay in circuit, to me its complicating a simple circuit.


beerchug
Re: Wiring diagram for BSA A50/65 racing bike ? [Re: DavidP] #518158
12/10/13 6:18 am
12/10/13 6:18 am
Joined: Jul 2009
Posts: 3,549
Vic. Australia
P
Pete R - R.I.P. Offline
In Remembrance
Pete R - R.I.P.  Offline
In Remembrance
P

Joined: Jul 2009
Posts: 3,549
Vic. Australia
Originally Posted By: DavidP

Where do we get this crap?
The alternator produces what it produces. If that energy is not used for work it is turned into heat by the regulator. The energy required to spin the rotor remains the same.
1/10 HP = 74.6 W, not likely!


When you learn a bit more,you'll see that it's not crap.If you connect the output leads of the stator to nothing,it's not taking horsepower from the crank.
When you connect them to a load,and a zener is a load,and a rectifier regulator is a load,it takes energy to turn the rotor.

With a 3-wire single phase stator,one wire connects to only 1/3 of the coils (2 coils).If you connect that one to the rectifier AND the commom wire which connects to the other end of those coils,you get 1/3 of the potential output.When you connect the other wire up to the rectifier,you get the other 2/3 as well.

Let's just use the wire that connects to two coils,and have 40W output at 5000 rpm.A brushless alternator is about 65% efficient,so that takes 61.5 watts from the crank to get that 40W electric output.

If you connect up the other wire,that's another 123 watts from the crank at 5000 rpm.That's why I wouldn't do it.
This engine isn't going to stop at 5000 rpm.It may rev to 7500 rpm.That 123W at 5000 rpm could be 135W at 7500 rpm (almost 0.2 bhp).

It may not be much on a 45 bhp engine,but it's still there.At lower rpm,most of it is still there (an even bigger percentage).

Re: Wiring diagram for BSA A50/65 racing bike ? [Re: steevg] #518160
12/10/13 6:36 am
12/10/13 6:36 am
Joined: Sep 2013
Posts: 1,733
Pacific northwest
Q
quinten Offline
BritBike Forum member
quinten  Offline
BritBike Forum member
Q

Joined: Sep 2013
Posts: 1,733
Pacific northwest
Kill switch ? , Is that a normally closed , momentary disconnect button switch in your diagram ?

A normally closed kill switch can/will reconnect power to the coils when the button is released , is this part of the plan ?

Is there a reason for 2 switches ? You could locate the power switch as the kill switch and kill 2 birds with one stone , eliminate the relay and simplify the wiring

.... if its a lanyard kill , well then nevermind ....

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