Ossa Lighting.

[bigian]

Hello,

I am looking to do the upcoming Lands end trial on my 75 Ossa Mar. I will have to put lights on the bike for a full MOT. Can anyone help with some sort of simpe Wiring diagram.

It currently runs with Motoplat Ignition which gives me 5 wires Black and Blue which are for the coil, But have not much idea which of the other wires to use for which lights.

I have a green,red and white wires coming from the stator.

Will i have to use some sort of A/C converter to stop the bulbs from blowing. I really don't want to run a battery.

Any help would be great.

Cheers, Ian

[chaindrive]

did you find a wiring diagram ? I have one but not sure how to attach it

[ronwright]

I have an Ossa SDR which I am rebuilding - the wiring harness is missing. Did the owner of the MAR succeed in getting a simple wiring diagram - can he share it with me

[stecks]

will this help...? Peter

[ronwright]

Peter - thanks but my magneto has 5 wires coming from it - the blue and black ones power the coil which leaves 2 yellow and 1 red remaining ?

[stecks]

Peter - thanks but my magneto has 5 wires coming from it - the blue and black ones power the coil which leaves 2 yellow and 1 red remaining ?

Sorry. Not been on for a while. I am no expert, but I suspect the Explorer didn't use a battery, perhaps to keep the weight (and the expense) down... and so the extra wires may have run the lights directly...? Can you put a meter on the wires in question to see what output they are giving with the motor running and perhaps work it out from there? The diagram I posted shows a battery in the system. A steady feed through a switch, through the bulb and down to earth should put a bit of light on the matter... It would need a headlinght, a tail light, and a brake light switch. Could these three be fed by the three extra feeds? Unless anyone else has any suggestions...?

[greenwing]

I have had similar difficulties in reconstituting the lights on my 1972 MAR. All the original wiring has been stripped so I am starting from there. What I have noted is that there are 5 wires coming from the motoplat, blue, black, whit red and green. The blue and black go to the coil which would seem correct as the bike starts and runs very nicely. There was no provisions for a battery in this bake, no voltage regulator and such. I assume the lights ran of unrectified AC power. From what I have been able to infer from my investigations are that the white wire might supply power to the headlight, the red wire might power the tail light and the green might power the brake light ( though I see to accommodations for a brake light switch). I assume the power return is through the frame and engine back to the motoplat.

I have been unable to find any corroborating information for my observations. Would any one be willing to enlighten me?

[ossa72k]

Hi,

Just joined the forum and have a similar problem to you.

Did you find a solution?

I too have 3 wires (other than to the coil); yellow - which is

for the headlight; green which is for the stop light and

red(but sometimes its white) for the tail light (details taken from a Motoplat site).

I too want to run without a battery.

Can you (or anyone else) help with a diagram and a list

of the parts needed.

Thanks

[stecks]

I found this somewhere. It may be useful...?

[poor1]

Did anyone manage to succesfully wire one up without a battery and regulator?

[lotus54]

I have a diagram  here- I just need to find it.

 

I have a 74 Explorer that is wired up with no regulator or battery. Lights are not very good- but do work.

I'll try to find the diagram. (might be the same as above?)

 

mark

[lotus54]

I have a 'colourized' version someplace..

 

[pmk]

Reviving an older topic.

The other day, I wired the 73 MAR for lights.  The bulbs I used were 6 volt.  No plans to ride at night.  The first run the lights operated fine until I reved it while riding.

both headlight and taillight failed.  Checked the voltage and found far more than 6 volts AC.  

I operated both lights off the one designated wire for the headlight, yellow I believe.  Since my headlight is 15 watts and the tailight is minimal the system was not heavily loaded except at idle.

So with this said, it becomes apparent I need a voltage regulator.  The easiest method would be to find a proven single wire style, that simply bleeds off excess voltage to ground.  My KTM had a regulator like this, but was 12 volt.

i can find many low cost regulator / rectifiers that are 4 wire.  Guessing two feed wires, 6v AC and ground, and two outputs of 6v DC power and ground.

Not sure if it is possible to utilize only the input side to regulate 6v AC, and cap the rectified outputs.

Price is good at $10 delivered.

Any thoughts.

[pmk]

Ordering parts today.  Expect good results and a simple solution.  Not expecting lights to be superb for higher speed night riding / driving, but acceptable for daytime road use and night rides at slower trials speeds.

[pmk]

6 volt AC voltage regulator arrived Friday.

For my setup, I am running a 6 volt 10 watt headlight, and a 6 volt 5 watt tailight.  I did not bother adding the brake switch and brake light or horn.

The MAR apparently has 3 generator output coils besides ignition.  The higher output yellow lead on my machine is for the headlight in original setup.  Another coil was for the tail light, and the third for brake and horn.

With my combined electrical load at 15 watts, the headlights coil, rated for 30 ish watts is more than needed.

The original design, like many other 60’s and 70’s designs, utilized 6 volt AC to drive the headlight.  By design, they matched the headlights requirement, to the ouput coil capability, and things worked.  Voltage would climb and fall, but it worked.  Same on tne other output coils.

A couple weeks ago, when I first powered the lights, all was good, until I the rpm increased.  Because increased rpm drove the output to max, and the bulbs could not consume the power, voltage rose until the bulbs burned out.

I decided on getting. Kedo 6 volt AC voltage regulator.  AC only, and no rectified DC as there is no battery or horn.  If you plan to use a horn or flashers you might need DC for those to operate correctly.

The Kedo regulator is supposedly a reproduction for a Yamaha XT500 and others.  Electricity is not brand loyal, so it was an easy hookup.  The regulator has a single yellow wire, that coincidentally matches tne OSSA yellow 30 watt wire.  The regulator case is aluminum pot metal and must be grounded.

In simple terms, the regulator is basically a controlled leak.  Set in the 6 volt range, as voltage increases with revs, the regulator holds the voltage steady, bleeding excess to ground via an internal variable load.

I mounted the regulator on my resto mod MAR to tne left side feame and headtube gusset.  One  small 6mm hole.  The hole itself was burnished to remove powdercoat, and then to be certain, I verified low ohms from the burnished area to the engine center case.  The reading was bouncing between 0.0 and 0.2 ohms.

The wire hookup had me retain a single bullet female connector on the oem yellow output harness.  For my homemade chassis harness, I installed a male bullet connector where I placed two wires.  One wire ran off the lights, while the second ran to the regulator.  The regulator arrived with a bullet connector crimped to the lead, so I simply made a match there with no mods.

To save money in case this did not go as planned, I only installed a tail light bulb.  I expected that for the cost it was smarter if it popped.  Also, at 5 watts required, if the voltage was not regulated, it would fail easily.

Fired it up, set the switch for lights and the tail light illuminated.  With rpm increased, the tail light did not fail.  AC voltage checks were bouncing about, but never above 7 volts.  Ideally, this will not be exceeded at full revs.

Installed a new headlight, and tested again still working.

Not exactly sure if or how this could help others, especially if you must run power from all three output coils.  But did want to share if needed.