1949 WL electrical issue

1949 WL Flathead electrical issue

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The 5-2-4
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Bikes: 1949 flathead WL 74 ci,1971 XLCH ironhead 900, 1976 FLH Shovelhead 1200
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1949 WL electrical issue

#1

Post by The 5-2-4 » Thu Nov 08, 2018 10:48 pm

I am brand new to any style of forums so I am hoping someone smarter than me can help. I have a 1949 Harley WL I have owened 3 trouble free years until now. History of bike is it has been converted to 12volt. I have replaced the condensor and points, new relay and rebuilt generator which was polarized. I have checked and cleaned all ground points from relay and negative terminal on battery. However the problem persists, everytime I attempt to attach the positive cable to a fully charged battery I get big blue sparks. I ran the bike like this for a while but it ate my battery so I tried to isolate the problem and here is what I have determined. The wiring is fine from battery to ignition switch and from ignition switch to relay. I was able to determine this by unconnceting every wire in the route and re attaching the positive cable with no spark. However I get the big blue spark when the wire is attached to the relay. I ran a jumper from the positive terminal to the relay and again got a big blue spark. I would guess the relay is problem but it is new and I have limited experience with electrical issues. Please help if possible and I hope I provided enough info. Mike



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Re: 1949 WL electrical issue

#2

Post by awander » Thu Nov 08, 2018 11:42 pm

It sounds like your relay is stuck in the closed position.

When you attach the wire from the battery, current flows through the non-running generator to ground, draining the battery.

Pop the cover off the relay and see if the points inside are closed when the bike is not running. If so, that is the problem.

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Re: 1949 WL electrical issue

#3

Post by RooDog » Thu Nov 08, 2018 11:47 pm

Mike....
Welcome on board...
Now, since this has been converted to 12Volt, tell me, or better yet a picture, of what you are calling a "relay". I big blue spark usually indicates a dead short to ground. Most 12V systems use a boxy regulator of some sort either mechanical or electronic. Or perhaps you have an electronic relay lock a like replacement for the stock cut-out relay in which case a call to the manufacturer may be in order.
RooDog

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Re: 1949 WL electrical issue

#4

Post by Buddhahoodvatoloco » Fri Nov 09, 2018 12:04 am

Hombre, you have a short. Review all your wires, all of them.

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Re: 1949 WL electrical issue

#5

Post by 1950Panhead » Fri Nov 09, 2018 2:15 am

It sounds like your relay is stuck in the closed position.
Your cutout relay is stuck in closed position, remove cover and pry points up.
It will probably happen again, 30 days or fifty years, does not matter, get another one.

The 5-2-4
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Re: 1949 WL electrical issue

#6

Post by The 5-2-4 » Fri Nov 09, 2018 2:21 pm

Thanks for input...will pop cover off relay and check...keep forgetting just because it is a new part doesn;t mean it will always work...

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Re: 1949 WL electrical issue

#7

Post by RUBONE » Fri Nov 09, 2018 2:54 pm

If your system is 12 Volts you do not have a simple mechanical relay, those are used on three brush 6 volt systems only. If your regulator is 12volt and mechanical it will have two components inside, a relay and a regulating coil unless it is the large police type with three components. But it doesn't sound like you have a mechanical regulator or you don't know how to identify what you do have.
Post pictures of your system, Type of generator, (H-D or Cycle Electric or some clone) picture of your control device (Regulator, either mechanical or electronic), and the switching system, etc. Trying to troubleshoot electrical problems blindly is merely a waste of time. Bhuddahood's response is the best. You have a dead short somewhere, but where? It can be internal in any component or it can be external like a pinched wire or a hot lead connected to a grounded post, etc. Get out the camera!!

The 5-2-4
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Re: 1949 WL electrical issue

#8

Post by The 5-2-4 » Fri Nov 09, 2018 10:10 pm

I am technology challenged so pics won't work for me, I still have a slider phone which I love. I popped of the relay cover and it is mechanical with 2 seperate points that open and close. A set of points in the front of the cover and a seperate set at the rear of the relay. What I was able to determine is that when I remove the power wire from relay to generator, and apply power to the relay, the set of points at the front of the relay open and stay open until I remove the power and there is no spark. But if I re attach the power wire from relay back to generator hugh sparks again. I fashioned a totally new ground wire ror the generator and moved it to a different place on the frame and this had no effect, still sparks. So the only time I get no sparks is when the power wire from relay to generator is removed. Again, I am an electrical idiot but my reasoning is that the problem is in the generator...any further thoughts would be appreciated. I have removed EVERY wire on the bike and inspected and cleaned and looked for problems and found nothing that looked out of place or burnt or such. Thanks again...Mike in MN

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Re: 1949 WL electrical issue

#9

Post by awander » Fri Nov 09, 2018 10:15 pm

Are the terminals on the relay marked?

What wires are going to each terminal?

For instance, the A wire from the generator goes to which terminal? Anything else on that terminal?

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Re: 1949 WL electrical issue

#10

Post by RUBONE » Fri Nov 09, 2018 10:57 pm

What you are describing is a regulator, not a relay. Try to give us some info to work with. Big sparks tells us nothing other than their is a direct short somewhere.

What markings or name are on the regulator? It could be stamped A-F-B or some similar combo.
What is stamped on the generator? A name or a series of numbers such 65A 12V or the like.
The generator doesn't use a "ground wire" it grounds directly to the case where it is driven.
there should be a wire to the regulator terminal marked B or B+ that goes to the ignition switch, same terminal on the switch as the battery (hence the B).
The other two terminals on the regulator connect to the two terminals on the generator marked A and F.
The only ground wire is from the battery negative to the frame tab, everything else grounds through the frame and engine.

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