Airhead R75/5 poor idling and carb synchronization issue

[happy wanderer]

The power for the light can come from anywhere, it does NOT have to be the bike. A separate battery eases the load on the /5 electrics and doesn't introduce another variable.

I have seen first-hand a couple of times where the strobe was not as constant or regular as it should have been - which may have caused the effect of "not as bright" - and that did point directly to the issue in those cases. This was with a Craftsman inductive light, which I still have in my garage but haven't needed for a while...

I realize the power source is not relevant and in fact, sometimes it is better to use a 12VDC source that is not connected to the bike being tested.

The point I was getting at is that I think the intensity of the light itself changing is likely due to missed pulses i.e. coils not firing, bad wire, worn out resistor cap, bad plug. The misfires could create that illusion of less light intensity. So I do not think that the timing light (when it does fire) is any less or more intense though, it just looks that way.

And yes, when the bike is missing or misfiring you definitely see the evidence on the timing plate on the flywheel. It disappears, jumps and generally is just not stable. Your advice to move the light side to side is a great way to figure out if it is only one side. This usually tells me to look closer at plugs, wires and caps. If it is both sides, the common components are now the coil, ICU and bean can including the connectors and wiring for those parts.

 

[htwashere]

One more thing occurred to me - Note the brightness of the strobe. If the light on one side is dimmer than the light on the other side, or is not as steady and regular, then the dim side has an ignition problem (bad coil or cable or cap or plug).

Hi Pauls1150, so this weekend I went ahead and tested the timing using the strobe. I noticed that my timing is off. So when I went back to adjust. Before making adjustments, I decided first to use a test light method to see how/why I was indeed off. What I realized on my bike is that, on one lobe of the cam, my timing is right on (test light came on at the F mark). As I turn the crank to the next spark, it is off. As a result, the overall timing is actually off. I fiddled with the adjustment and finally got the timing (using strobe) correct. I put my idle jet mixture back to the reference point and went back out for a drive. This time, I thought overall, the ride has much improved, and best of all, I no longer have the crazy idling at stops! When I came back with the bike fully warmed, I did a bit more synchronizing, but to be honest, with my noobie tuning skills and lame ears, I honestly could not really tell if I have make it any better, it seems that, with the reference idling jet mixture and the fuel cable on full release (with slack), AND the choke fully off, I think that is the best reference mark for my current machine

By the way, regarding if the strobe is brighter on one side or not, as per all the responses here, I do not see any difference on either side (mine is the inductive strobe). And the shorting method, it seems to be better after the timing is corrected, but I would not say that I make great stride with it. I am going to forget about this shorting business for now, the bike seems to run rather well...thanks everyone for contributing into this journal...now, onto looking into how to replace the clutch! any advice for me there?

Henry.