Cb450 wiring issues

Leetillman351

Leetillman351

Active Member
Hello all! I'm new to the thread and have just began my first build on a 72' cb450 twin k5. I'm having issues getting is started, I cleaned and soaked the carbs, new wire harness, changed the oil, checked compression and spark, and had it all. Installed a pamco ignition, but I'm having trouble timing it. I drained the oil to remove the stator cover to observe the timing marks, but whenever I have a timing light hooked up, I get no flash whatsoever, even after 5 or 6 turns of the alternator.

I have the light hooked up to the battery's positive and negative, and the clamp attached to the spark plug wire, and nothing. I have checked and triple checked the wiring and I cannot find any issues. I got it running for about a minute after I installed the pamco, but the carbs were running so rush the oil even smells like gas after I drained it.

The pictures of the oil is after attempting to get it running for a few days, other than that it is brand new oil.
Any help would be appreciated!
 

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First, congrats and welcome!

Second, you do not need to drain the oil to remove the stator cover and check the timing. You should either put it on the center stand, or better yet, find some way to get it to lean slightly to the right. I put a small piece of wood under the left side of the center stand. Or you could have a friend hold it or prop the right side of the frame on something since you don't seem to have a center stand. If you set it up this way, only a very small amount of oil will come out when you take the cover off and you can even run the engine with the cover off and oil in.

Are you trying to do a static timing with a regular light bulb turning the engine slowly by hand, or a dynamic timing with a real strobe timing light and the engine running?

I also have a pamco in my '72 450.
 
I have a dynamic timing light: can I still use this to slowing turn the motor by hand? Or do I need a regular light bulb for this?
 
put some fresh oil back in
you can use the strobe light turning the engine over with the starter that will work fine for an initial "static" setting on the LF mark
pull the sparkplugs out and ground them while doing this to ease the load on the starter and battery
if you are having trouble with the carbs just leave them dry while you set the initial static timing
then get the bike running and recheck and set timing to the full advance mark at 3000+ rpm's
this is the important one to set ,before you ride,the full advance
once you have that set you are done with the pamco there is nothing else to do
 
For static timing I just use a regular bulb (old gauge bulb) connected between the yellow or blue wire from the points/pamco and ground. I then slowly turn the engine using a socket wrench on the alternator. Doing it this way I can get it almost dead nuts on.

Then I use a timing light with the engine running to verify idle timing and check full advanced timing.

There is an article somewhere about how to do this. I will try and find it.

Also, I have heard that running your bike without a plug installed or properly grounded can possible fry the pamco board. Just something I heard and can't confirm.
 
Awesome information guys, I appreciate it. I have it at my warehouse so when I get to work tomorrow I'm going to check all wiring one last time, and go get a light bulb and try this out on Saturday. I'll keep y'all updated!
 
yeah I wouldn't risk not having a plug on the wire and grounded so as not to maybe hurt the pamco circuit board
just don't fall into the trap of trying to get the idle timing and advance timing BOTH spot on
the only one that matters is full advance timing and after setting that don't even bother trying to reset the idle timing if it is a little off after setting full advance it doesn,t matter just run it !
 
So I looked over all the wiring multiple times to check for any shorts or any disconnected wires and everything was spick and spam. However I was getting nothing. The headlight turned on, tail light, brake light, indicator lights all worked. I rigged up a static timing light to the engine fins and spark plug wire itself to attempt to time the ignition, and I turned and turned the alternator and got nothing.

The pamco is installed correctly, the coil wires were connected properly and cleaned, I had a fully charged 12v battery: what am I missing??

I'm at witts end with these wiring issues, any help is appreciated.

Side note: the bike did start for about a minute last week, then I installed a sparck moto regulator/rectifier and since then I have not been able to get anything. I disconnected the rectifier and all other connections not needed to start the bike just to make sure it was getting enough power as well.
 
Is it possible I fried my pamco? If so, how do I test it? I looked over all the pamco connections and everything looks fine, intact and not signs of stress or overheating. I'm desperate at this point :( :-[
 
Leetillman351 said:
I rigged up a static timing light to the engine fins and spark plug wire itself to attempt to time the ignition, and I turned and turned the alternator and got nothing.
Click to expand...

When you do a static timing, you don't connect the light to the spark plug wire, you connect it to the wire going from the pamco to the coil.

I found the article here:
http://cincinnaticaferacer.com/wp-content/uploads/2011/07/IgnitionTiming.pdf

When you do a static timing, you aren't trying to see the plug actually fire. You are trying to see when the "points open and close" to make sure this is occurring at the right time so the coil will fire at the right time. Since you have a pamco, you are trying to confirm that the transistors are opening and closing at the correct times.
 
try isolating the pamco and coils from the main harness and just jump them straight to the battery and see if you get fire at the plugs
this is all I can think of doing at this point
if you still dot get fire then it could be the pamco
you do not have the condensors wirede in with the pamco ?
 
When you do a static timing, you don't connect the light to the spark plug wire, you connect it to the wire going from the pamco to the coil.


I tried that as well, I connected it to the wires on the pamco plate and still nothing.
 
I don't have the condensers wired in, if I'm not mistaken, the e advancer replaced the condensers? If I'm wrong I will feel very very stupid and be out $195..
 
Ok that's one thing I've done right.
The bike started last week on both cylinders, so I know it worked and the coils were working. I installed a sparck moto rectifier and attempted to start it and the green wire got so overheated it melted the plastic connector. But there is no visible damage on the pamco so I'm having trouble here.
 
well the pamco is a mysterious deal for me as well
mine finally fried after 12,000 miles and i can't see as it was anything but worn out
i sent the pamco back for repair
however mine took a couple rides to fully fail finally left me starnded
i verified it was bad by putting the points/condensor back in with same coils
and am riding like that now
you should do the same if it runs or has good spark with points/condensor then the pamco is failed
 
There's a huge thread on Honda Twins about the PAMCO. If you search for my username I outlined a testing procedure that I don't remember now.

I got one with a bad unit one one side and then the other side failed. Pete's good about replacement, but I'm not convinced of the quality after a couple years of this sort of thing cropping up. I agree with XBLAHBLAHBLAH - go back to the points. Robert Pirsig managed to adjust his, and he was crazy.
 
My first pamco unit was a dud too. My replacement has been running fine though.

If this one ever fails, I might just have to spring for one of the ones from Charlie's Place. At least those don't look like a science experiment.
 
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