
April 25, 2020

New here. From Australia.
I picked up my first Bantam a few days ago. A B175 in red that looks pretty good from a couple of meters away which is nice. Looks like someone has done a bit of cosmetic work on the tins at some point but it definitely suffers from some poor work underneath by previous owners.
When I got it almost everything was loose with a lot of parts barely hanging on (exhaust header, baffle, foot peg mounts for instance). Some things couldn't hang one at all and it was missing an axle nut and one battery clamp nut. After a full going over of the fasteners, points set and cables re-routed and adjusted it seems to run reasonably well. It came with receipts for new rings, seals etc. with a top end rebuild only a few 100kms ago which is odd considering it seemed to be barely hanging together....
Main issues are with wiring and I have a few questions here.
- It seems like I am running total loss electrics. There is a stock regulator in place however the three connections at the base have been clipped off and go nowhere. The wiring is a total shambles with terrible hack jobs everywhere.
- Is there a sensible reason why the reg/rec wires would be clipped?
- Before I rewire things is there an easy way to check the stator's output to make sure it is functioning correctly?
- Is it worth going solid state and electric ignition? If so what are the recommendations?
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Thanks in advance.
Nick
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1969 BSA Bantam B175
2004 Harley Davidson Sportster
1998 Suzuki DR350
2007 Suzuki DR650SE
Grand Prix 160cc Victa Mini Bike

June 23, 2013

Hi Nick and welcome. A lot of owners would be tempted to go down the 12V -ve earth route if the bike needs work on the electrical system. That gives a good choice of regulators, LED lights, etc. If you decide to do that, there is an excellent topic in the Tech Archive by Lone Wolf. It's usually best to get the system running OK on points, condenser and coil before investing in an electronic system, as that won't cure basic problems. There is also a lot of discussion on the forum covering pros and cons of both going electronic and which system is best.
To test the stator, you can do a resistance check, each coil should be not more than a few ohms, with a slightly higher reading from all 3 in series. A broken wire between coils is a fairly frequent occurrence. As for clipped terminals on the regulator - burnt out, bafflement, frustration?
Can you tell me what the 2 trail bikes are in your garage? The white one looks familiar - Moto Morini? Suzuki?

April 25, 2020

Hi Cocorico,
Thanks for the quick reply, I'll check out Lone Wolf's thread as you suggest. Have also just discovered that Oz Bantams make a plug and play electronic system here in Australia although they seem to be closed due to the current Covid situation.
The bike is actually running quite nicely now after a bit of fettling so I don't think I have too much aside from electrical gremlins to worry about.
The two dirt bikes are both Suzukis, A 98 DR350 and an 07 DR650. The 650 is my long distance travel bike and the 350 is the weekend woods/trail bike. I've sunk a fair bit of time and $ into both but they have done me well and are fantastic machines. I'm looking forward to having the Bantam setup for nice sunny Sunday rides.
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1969 BSA Bantam B175
2004 Harley Davidson Sportster
1998 Suzuki DR350
2007 Suzuki DR650SE
Grand Prix 160cc Victa Mini Bike

February 24, 2015

Nick are you sure its not already been fitted with a modern 6v reg rec....my B175 has been and its fine.
And has it still indeed got the 6v sys still.
Mine has I prefer to keep things std.
Dont be in to much of a hurry to fit an electronic ignition sys in the hope it will cure all it wont...nothing wrong with the very simple points sys...in fact it has a lot going for it...ie you can fix it at the side of the road and most bits are cheap.
Can you stick a voltmeter on the batt and run the motor....and look see what volts are being put into it.
P.S. some modern volt meters cant cope with the Bantam sys...drives em mad....I just fit long lead in my probes to keep the meter away from the bike a bit more...stable then.
Nick.
My Bantam video https://www.you.....jpOFmzRZRI

April 25, 2020

Ah ok, were the stock regulators a bit rubbish? Or do they fail and cook batteries?
Cheers @spacedmarine. It’s a 74 Chev Luv. It belonged to my grandparents originally. First car I ever drove. 4 speed column shift. Puts a smile on my face every time.
1969 BSA Bantam B175
2004 Harley Davidson Sportster
1998 Suzuki DR350
2007 Suzuki DR650SE
Grand Prix 160cc Victa Mini Bike

April 25, 2020

nickjaxe said
Nick are you sure its not already been fitted with a modern 6v reg rec....my B175 has been and its fine.And has it still indeed got the 6v sys still.
Mine has I prefer to keep things std.
Dont be in to much of a hurry to fit an electronic ignition sys in the hope it will cure all it wont...nothing wrong with the very simple points sys...in fact it has a lot going for it...ie you can fix it at the side of the road and most bits are cheap.
Can you stick a voltmeter on the batt and run the motor....and look see what volts are being put into it.
P.S. some modern volt meters cant cope with the Bantam sys...drives em mad....I just fit long lead in my probes to keep the meter away from the bike a bit more...stable then.
Nick.
Hi Nick,
Pretty sure there is no regulator anywhere. I haven’t taken the tank off but have looked underneath. No charge on the battery when motor is running. Already checked that. Engine dies if I try to run lights and ignition at same time. Less than 6v showing on multimeter.
yeah points have some up sides but the ease of electronic is always better for me. I run electronic in the Chev luv for instance and carry a set of points in the glove box for an emergency. Condenser is still screwed to the side of the dissy.
Nick
1969 BSA Bantam B175
2004 Harley Davidson Sportster
1998 Suzuki DR350
2007 Suzuki DR650SE
Grand Prix 160cc Victa Mini Bike

June 23, 2013

nickjaxe said
...I just fit long lead in my probes to keep the meter away from the bike a bit more...stable then.
Social distancing for DMMs now, and it works for them too. Nick (Oz), they were never fitted with regulators back then, just rectifiers and load balancing. Nick (jaxe), I think the original post said the terminals were clipped off and probably running on total loss - which could still give a reasonable running time. Looks as if you need to look at your wiring and compare what's there with a wiring diagram (probably in FAQs) to see what's what.

April 25, 2020

Looks like I need to eat a tiny slice of humble pie.
I pulled off the old rectifier (Thanks cocorico) to get a photo and a better look.
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Low and behold. This little guy was hidden underneath.
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It still isnt charging though. I'm reading lower voltage from battery when running than with the bike off.
Definetely needs to do some tracing with a diagram and check the stator.
1969 BSA Bantam B175
2004 Harley Davidson Sportster
1998 Suzuki DR350
2007 Suzuki DR650SE
Grand Prix 160cc Victa Mini Bike

January 9, 2013

hi Nick a very nice Bantam somone got to tell you ,., IT normal NO siign of any charge on TICKOVER on a bantam you or the briver is the charing REGUTATOR in a system that DOSNOT have a regulater fited in the system & if you do ever see the the charge rage at wot is a normal system the batery will soon be empty ,., regula use expected by BSA to be enuff to keep us alll chared & on the road ,.,. thanks for the photos very nice

April 25, 2020

sunny said
hi Nick a very nice Bantam somone got to tell you ,., IT normal NO siign of any charge on TICKOVER on a bantam you or the briver is the charing REGUTATOR in a system that DOSNOT have a regulater fited in the system & if you do ever see the the charge rage at wot is a normal system the batery will soon be empty ,., regula use expected by BSA to be enuff to keep us alll chared & on the road ,.,. thanks for the photos very nice
Ah, I should have figured that out myself. Thanks for the tip.
I'll run it in the shed tomorrow evening and see if the lights brighten and dim with engine revs. That should be a decent test.
Got a safety certificate booked tomorrow morning so fingers crossed it passes and will be legal on the road for some proper testing. Should be able to rig the multi meter with some duct tape to the bars for a road test.
1969 BSA Bantam B175
2004 Harley Davidson Sportster
1998 Suzuki DR350
2007 Suzuki DR650SE
Grand Prix 160cc Victa Mini Bike

April 25, 2020


June 23, 2013


April 25, 2020

cocorico said
Did you measure the voltage output of the stator? That should vary with revs - disconnect from the system though first.
I measured DC voltage at the battery terminals. Haven't tested the stator yet.
When you say "Disconnect the system" what exactly do you mean? Disconnect the rectifier?
1969 BSA Bantam B175
2004 Harley Davidson Sportster
1998 Suzuki DR350
2007 Suzuki DR650SE
Grand Prix 160cc Victa Mini Bike

June 23, 2013

My simple Alternator test bulb kit if they both light up brightly as you increase revs its working ok
measuring AC voltages particularly with a digital meter can give some misleading readings if there are shorted turns on the stator
and you really need to replace that rectifier with a modern silicon one
D? - D10- D14 Bantams 350 AJS -500 Triumph http://bsanotru.....lfire.com/

November 5, 2012

Looks utterly gorgeous to me - persevere with the gremlins and she'll pay you back, these were proper grown up bikes - good luck!
1950 D1 (Ex Hawaii!), 1936 Ariel 500 OHV, 1923 Raleigh Model 2 350 SV, Various bikes hidden from the Missus in sheds, under floorboards etc., etc., ...
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