bypassing the ignition key for my 1966 Suzuki b105p

[flashyeight]

The key is broken on this machine and I was wondering if anyone could help me with just direct wiring the wires to each other. There are 5 wires in total. Black, gray, yellow, green, and red/white. I can't seem to find any wiring diagrams and have tried a couple of combinations with no luck having a spark from the spark plug when the turning over the engine.

Thanks in advance, this is a great place to find information.

[oldjapanesebikes]

It may not help you at this stage, and I'm not sure if that ignition switch is similar, but most Suzuki ignition switches are quite easy to take apart and play with - either to rekey, clean or to remove a broken key. On most of them there is a release tab which you can depress with a suitably shaped pin - what I use is a ground down allen key. Push in the tab, and the lock barrel just drops out. You can see it inserted in the release hole in the photo. The only real trick is to not lose any of the little springs - don't ask me how I know !



This photo shows the lock barrel and the allen key is pointing at the lock release tab.



New keys already cut for your lock can usually be located if you know the key code (stamped on the lock face and/or the key). I usually buy them from this fellow.

[flashyeight]

Unfortunately when I bought the bike the lock barrel part of the ignition switch was missing.

This is the problem I had with it, when I was turning over the engine and using a screw driver to turn the plastic insert i would get a spark to the spark plug. But could not find a definite spot where I could keep the plastic insert. I was thinking of maybe just putting a toggle switch until I buy a new ignition switch ($40.00 on ebay from Thailand), but I'm not sure what wires to hook up to each other until then.

Thanks for your help though.

[Madbuffalo]

Ian, I had no idea these keys were still available. Thank you!

[oldjapanesebikes]

Looks like the B100P uses the same switch - does this wiring diagram help ?

[flashyeight]

Thank you Ian, it is the same wiring as mine.

If I only wanted to get the bike started and spark plug firing it appears to me all I have to have hooked up is the black wire from the flywheel magneto to the black wire going to the ignition coil? Do you know if anything else is needed?

[oldjapanesebikes]

I'm not a wiring expert but there are at least a couple of folks on the board who I'd say come close Looking at the diagram I would have said green to white with red stripe should close the daytime running circuit, and additionally yellow to grey should get the lights working. Black at least on the ignition switch looks to be a cutout as in the switch it connects to ground. Best you get some confirmation though from others.

You can access a higher resolution picture at this url. Its about 2.5 MB, so I hope you aren't on a dialup ! Take a close look at the switch matrix, and at the switch connection labels

[tz375]

Ian,

I'm no expert either but I agree. The ignition is black from the coil to black at the alternator/stator to run and the switch grounds it to teh E (earth) terminal for OFF. May need to pull the flywheel to clean and set the points.

Interesting that the switch grounds the battery for lighting.

[jabcb]

Use a multimeter to test for continuity between each of the wires for all key positions. Make a little chart like the one in the wiring diagram. Should be straightforward to figure out what wire is what by comparing the charts.

Interestingly simple wiring diagram. It uses a half-wave rectifier. Should be able to double alternator output by rewiring stator connections an using a full-wave rectifier.

[flashyeight]

Thanks for the posts, I finally figured out the connections to at least get power through the spark plug when I trun over the motor. It appears i am not getting enough juice to make the spark plug fire. I hooked a volt meter contact to the inside of the spark plug and the other contact to a ground. I have an old volt meter and it appears at some cranks I am getting around 12 to 14 volts max through the plug but no fire.
Is there a range it should be hitting to fire the plug?
I am assuming I need to start from the plug and work backwards to the ignition coil next, to make sure the ignition coil isn't bad, then the wire to the magneto.

[H2RICK]

Interesting that the switch grounds the battery for lighting.

Well, it actually completes the ground circuit of the battery so the battery can be charged by the C1 charging coil in the mag.

In both the day and night key positions, the switch completes the circuit for the ground side of the battery and the low output charging coil (C1) is thus allowed to send its AC current through the switch to the input side of the rectifier (SE) thus allowing the battery to be charged with DC from the output side of the rectifier (solid RED wire) and the rear brake light switch and the neutral light also to both be fed with DC through the ORANGE wire.....if I'm reading those tiny letters on the switch right.
In the night key position the headlight, running light and speedo illumination light(s) (HL) are cut into that same circuit (C1 + SE) mentioned above ALONG WITH the C2 charging coil. The C2 coil is of course cut in to cater for the higher load on the system that the night time lighting causes.
It's interesting how they run the AC current through the ignition switch before sending it on to the rectifier.

[tz375]

The plug should see 15,000 to 30,000 volts.

The coil should be 9 - 400 v AC (not DC). The coil has to be the right type and points must be clean. must be gapped and timed correctly. ET ignitions are very sensitive to timing, they must open at exactly the right time to get any power (or should that be close at the right time).

[H2RICK]

I'd be careful hooking up my voltmeter to the plug cap OR the centre plug electrode. Those are connected to the high tension side of the ignition coil and the coil puts out about 10,000 to 12,000 volts DC.
TZ thinks these old coils have a very high output but they typically do not exceed 15,000 volts.....and certainly not when you're kick starting them.
Such voltages CAN make a mess out of your meter....unless you have a VERY exotic meter.

EDIT: Just a thought but you ARE using a fresh plug with the correct gap......right ??

[tz375]

I know those were high numbers i quoted earlier. I was really indicating that they were way higher than the average volt meter on DC settings. At kickover they probably struggle to reach 12K volts, but that's still enough to fry a simple meter.

Did you check the resistance of the ignition coil and check the plug cap and make sure that the end of the HT lead is OK? If teh basics are not good, the system just doesn't work the way it should, so start with the basics.

[flashyeight]

Finally Success!!!!!
I took off the contact point, it was not completely flat and was pitted, I filed it down until it was completly smooth.

I then replaced the wire from the plug to the ignition coil, then replaced wire from the ignition coil to the positive wire of the toggle switch I installed, then replaced wire from the coils/point to the positive wire of the toggle switch, then hooked a ground wire from the frame to the negative wire of the toggle switch.

Started on the third kick!!!!!!! Runs like a dream.

Had to adjust the carburator a couple of times but that was it.

I figured it must have been the 45 year old wires and actually didn't want to buy a new $155.00 ignition coil. Still have to re-wire all of the lights but that is for a later time.

I want to thank you all for the posts and I am glad I was able to find this gem of a forum. I'll post a picture of this 4 month project and counting, later in the week.

Thanks again,