QT50 Key bypass

Good morning all! So I bought a rather neglected 1979 QT50 from CL. Described as not running but with a good engine I decided to take a change on it and see what I could do. My plan is to rebuild it and sell it and hopefully make a bit of a profit.

Things are going well, lots of parts have been replaced - carb, air cleaner, various cables, fuel lines, spark plug, ignition coil, etc. Cleaned out the bike and the tank and got it all looking good - painted a few parts and now I'm in the process of getting it back together.

The issue I have is the ignition. It came without a key or a title (not a big deal in my state). I tried pulling the ignition and removing the tumblers but I'm not 100% sure that worked or will work. I have the old style 2 selection ignition - off and run - and I'd honestly rather replace it with a simple switch but I have no idea what wires I need to connect to make it work. There are at least 4-5 wires coming up to the ignition and while I understand in theory how it works when you turn the key (I see the connections that get made in the ignition) I'm not 100% sure what I would need to connect to make it work. Any help would be appreciated. Pics are very nice as well!

I had everything together yesterday enough to try and get it started but it wouldn't. I was frustrated so I didn't check much but I know I was getting spark and gas so I think the ignition was the issue.

Re: QT50 Key bypass

Luke Vidacovich /

Did some research and found the proper wiring diagram for the ignition I have. Looking at the image attached I think I can connect the R wire to one side of the toggle switch and the By wire to the other side and flipping the switch should complete the circuit and allow the bike to start and run.

I guess I can connect the battery to confirm this even if I can't get the bike to start. Can anyone else confirm my logic please?

Re: QT50 Key bypass

Luke Vidacovich /

Well I tried a bunch of stuff last night with no luck. Spent 3 hours on it. Wound up breaking the ignition and now all I have is bare wires.

I can get the bike to go into the * mode and the oil light stays on but I can't get it to get into run.

I'm buying a new brake light bulb today because it should turn on when I'm in run so that will be my cue I've got it right.

Based on what I see I should see 6v with my tester at the red wire at the ignition. It flows directly from the battery. If I connect that red wire to the brown wire it should work. Brown goes to the engine on/off switch and then to the CDI. So that that point the CDO should be getting power from the battery.

According to the diagram everything else on the switch goes to nothing that would keep the bike from starting (horn, tail light, oil switch, ground for CDI).

I also think I may have a broken wire somewhere as for a while connecting the brown and red made the oil light come on - which is what connecting red and gray should have done.

How do I get to the connectors? Are they behind the headlight?

Re: QT50 Key bypass

my qt is the same, if i remember correctly just the black wire removed off the bottom of the ignition switch will do the trick and allow you to shut off the moped with the kill switch still. let me check and get back to you for sure.

Re: QT50 Key bypass

Luke Vidacovich /

Well at this point my ignition is completely broken - I broke the black plastic disc with contacts so I gotta figure out something. Thanks for the response.

Re: QT50 Key bypass

yea mine is broke as well, just disconnect the black/red wire from the bottom of the key switch, the bike will run. with mine when the key is in the off position none of the electrics but the headlight will work and when on everything works.

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