Bike won't start...1972 CB450

I picked up a project bike some guy on craigslist gave up on. My brother picked it up for my while I was at work...the guy said it runs, and when he went to demonstrate it in front of my brother he got it running and then it promptly died and he could not get it running again.

I checked the timing and it appeared to be way off. When I went to correct it per the timing procedure (http://www.hondatwins.net/forums/attachments/5735d1277953977-honda-twin-ignition-timing-re-posted-ignition-timing-1.doc), I found all of the screws stripped. In the mean time, I tested the coils and made sure that I got spark -- I did.

Now I fixed the stripped screws, and began to time it the way Bill's document prescribed, and noticed one thing: The 12v test light, when connected to either set of points, was always on. Points open, points closed, whatever, the light was always on. I ignored it after I read briefly someone said that did not matter, I set the timing so that both gaps were in spec at the LF and F marks (it only took 2 tries!), and promptly could not start the bike.

I'm thinking it has something to do with the test light always being on. Does anyone have any input?

(Note: I checked the oil, it was good although the drain cap was frozen on; I also did a compression test and got 175psi on both...Everything appears to be in working condition. I am stumped.)

Test light always on does matter. Test light should only be on when the points are open. The point at which they open should correspond to when the spark fires. Double-check your gap to make sure it's in spec and also make sure the points are properly closing when you rotate the crank.

Okay so I took another crack at it today.

I re-gapped the points, correctly this time, and hooked up the test light. One end went to the battery negative, and then one end went to the left side points per Bill's word document. The light stayed on the entire time, even when the points opened and closed.

Next, I was really confused, so I removed the light from the left side points and put it on the right side points -- same thing. Light stayed on the whole time.

After that, I dropped the alligator clip and it touched the engine, and the light lit up. I attached the light to the negative on the battery and random places all over the engine...and the light lit up. Apparently the engine is not grounded (I assume it should be...), therefore the condenser isn't grounded (it should be, right? By frame attachment?) -- I found a random wire that was ground (there are wires hanging everywhere, no electronics are hooked up), and attached that to the housing of the condenser. Now, when I touch the engine with my light, it doesn't light up. It looked like that was the issue! I went on re-doing the timing, as I removed the points while poking around, and I got the left hand side to light up right when it hits LF. Satisfied, I switch to the right hand side and the light is always on, points open or closed. Confused, I switch back to the left side points, and the light is always on again -- but not when I touch random parts of the engine!

What gives?! I'm assuming this is some kind of grounding issue...but I do not really know where to begin. I believe that I am wired up correctly...The two black/white stripes from the coils go to the black/white stripe wire from the harness (it has two ..receivers). The blue from the coil goes to the blue from the condenser and the blue from the points. The yellow from the coil goes to the yellow from the condenser and the yellow from the points. I believe the blue and the yellow wires are correct, because each side has a connector that accepts two male connectors, so I keep all of the colors together per the wiring diagram. I have not yet determined a permanent fix for the ground.

Edit - I just watched a video on how to time a CB350 and the guy said that you need to put an index card or something between the second set of points to stop the test light from being on all the time...However, he hooked his test light up to the positive side of the battery. Does this apply here?

Do you have a multimeter?

If you think the engine isn't grounded correctly, the ground cable is at the rear of the engine on the right side. It should be connected to one of the rear mount bolts and be attached to the negative on the battery.

Electricity flows from positive to negative. Power comes from the black/white wires to and through the coils to the yellow and blue wires. Then when the points close they connect the circuit. When you connect the test light you need to make sure you have the light connected to the correct part of the point, IE the spring.

IF your points are FILTHY, then the resistance across them will be MORE than the resistance through the light bulb in your test light. Electricity will take the path of LEAST resistance all the time, and if that resistance is infinite (DIRTY POINT) then they will never trigger the coil to charge and subsequently fire. MAYBE need new points or at least file and dress your old ones. Do NOT use Emory cloth or a nail file as the sand in them can cause the points even more damage. Use a point file or a very small key file.

I'm pretty confused.

There was no engine ground, so I ran my own up the side of the bike. I also ran one from the negative on the battery to where the coil mounts, so that the coil can be grounded also.

I got so close to setting the correct static timing, but random things kept happening to me. A coil kept changing polarity?? It was fine, then halfway through the light started staying on all the time again. I felt the coil, and it was hot. I started checking wires one by one, and one of the black/white stripe wires from the left side coil changed to ground?? I tested it by using the 12v test light on the positive side of the battery to the black/white stripe wire. When I disconnected the left side points from the left side coil (via the blue wire), that wire stopped being..negative, and the light no longer lit up.

Does this sound like it is supposed to happen?

How hot did the coils get? They can melt the internal insulation and ground out internally ruining the coil if they are/have ever been left on to long. There are resistance measurements in the manual to check the coils if you have multimeter. If they fail they are toast.