Pamco Electronic Timing trouble

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arudeseal

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1968 CL350

I have the cb350 electronic ignition from Pamco Pete. My problem is, that when I have the left side dead on, the right side is off, and with the right side on, the left side is off. The only way to adjust the timing, is to rotate the whole unit, affecting timing on both sides. Is there something I need to check on my end? Has anyone else experienced a similar problem?
Thanks,
Andrew
 
There is a huge hundred-page thread on the Hondatwins site troubleshooting this, among other Pamco pointers. Check that out to see how to bend the hall effect sensor and watch Pete argue with people about whether or not it's necessary. :-)
 
Re: Re: Pamco Electronic Timing trouble

Tim said:
Sometimes you need to split the difference. How 'off' is off?
Click to expand...

This here is a question with a hundred pages of answers, to rival oil-brand discussions or whether or not one should purchase an application-specific crimper :)
 
Well, to put this all into some perspective, keep in mind that the Honda owners manual has a procedure for static timing with the points and if you get the results that Honda describes, you are factory. With the Honda static timing method and points, you will always have some discrepancy between the cylinders, unless you spend the rest of your natural life screwing with the points to get the perfect match between the cylinders, and even if you do reach perfection, it doesn't last long with points. Perhaps just one good weekend of riding.

The PAMCO is a replacement for the points. It is better in many respects than points, but in some areas it is equivalent. The timing between the sensors is tested at the factory and set to be within 1 degree on the cam. That is 2 degrees on the crank, where the timing is checked. There are differences between each engine primarily due to the cam timing chain and therefore the 2 degree crank timing may not be available in an actual installation, but the difference in timing between the cylinders is no worse than it would be with points using the factory static timing method.

You should also keep in mind that the timing for the valves suffers the same fate as the ignition due to the timing chain and there could be an argument that having the ignition timing follow the imperfect valve timing is advantageous.
 
Now that is customer service! Thanks, Pete. I've spent more on worse stuff, with far less support, for machines 30 years newer. :)
 
arudeseal said:
1968 CL350

I have the cb350 electronic ignition from Pamco Pete. My problem is, that when I have the left side dead on, the right side is off, and with the right side on, the left side is off. The only way to adjust the timing, is to rotate the whole unit, affecting timing on both sides. Is there something I need to check on my end? Has anyone else experienced a similar problem?
Thanks,
Andrew
Click to expand...
One of the things to check before you go bending hall effect components is to double check your cam chain tension and then recheck dynamice timing.
 
Timing differences between one side and the other can only come for two possible sources - crank twisted, or pickups in the wrong place. Timing chain slack etc are relevant to the whole cam being off one way or the other but cannot explain one cylinder with respect to the other. In this instance it is possible that the crank has a slight twist.

How far out are we talking here?
 
teazer said:
Timing differences between one side and the other can only come for two possible sources - crank twisted, or pickups in the wrong place. Timing chain slack etc are relevant to the whole cam being off one way or the other but cannot explain one cylinder with respect to the other. In this instance it is possible that the crank has a slight twist.

How far out are we talking here?
Click to expand...

Well, the timing chain, just like any chain, can have a varying section length which would cause the timing for both the valves and the ignition to be different between the cylinders. The valve spring tension is also a factor as a stiffer spring will tend to stretch the chain more than a spring of lesser tension. We think of the back side of the chain as being absolutely taught, but in fact the above factors can cause the tension to vary.
 
That's possible, but just turn the motor a couple of rotations and that will all change. The chain is not rotating at the same point all the time. With say a 36 tooth cam sprocket at say a 94 link chain, it will be out by 14 links every three rotations.

So while it is technically possible and should be checked, the crank or pickups are more likely to be slightly out. It only takes a tiny tolerance to cause a difference in timing. Honda cranks are not splined the way that say RD Yamaha or XS650 cranks are splined and it's easy to be a few degrees out between sides.
 
I hope I'm not asking an obvious question here, but you are using a timing strobe light aren't you?
 
teazer said:
That's possible, but just turn the motor a couple of rotations and that will all change. The chain is not rotating at the same point all the time. With say a 36 tooth cam sprocket at say a 94 link chain, it will be out by 14 links every three rotations.
Click to expand...

This is a very good point and one that I must admit I had not thought of.
 
Wow, what a revival.

This engine was eventually completely rebuilt with a NOS cam and sprocket, NOS rockers, and new valves and guides. The cam holders were very worn before rebuild. Replaced with NOS holders on both sides. I can't theorize as to what exactly was causing the timing discrepancy, but now with the same PAMCO unit installed, the timing on both sides is spot on. The cam holders on these old engines are apparently commonly worn. Something to make sure you look into when rebuilding. If I had installed then new cam but left the old cam holders, I would have likely had the same problem, and the cam ends would have gotten chewed up by the old worn cam holders.

I don't time static. I always use a strobe.
 
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