Hi, again. I've been searching the site (and the general internet) and can't seem to find this info relating to my 64 CA72.
1. I am getting max 12.7 volts at my battery - that is when revving, i am getting + volts, just not going over 12.7. it turns over with the starter no prob at all. And runs like a champ (see next q)
I am thinking this is the best it gets? Maintaining the battery...
2. Bike idles and runs great - UP to about 45 - then won't go any faster, just tops out...My plugs are very white after a long run...to me seems like a lean condition - could this be related to the LEAN issue? or timing?
thank you, Chuck
Charging and lean condition
Since I've not been able to do any electrical work on my CA, I can't give you any definite guidance in relation to your first question, but it's possible the charging system/output works in a similar way to that of the later CB's (albeit without a regulator).
Basically, the CB's output half their charging capacity under normal conditions and you only get full output when the high beam is turned on. That's not the best explanation ever, so you might want to have a look at this video which explains it - and a way to improve the output - better than I can. Again, this is a guess, so do some checking with a multimeter to confirm, but also be aware that without a regulator, it's possible that doing this modification to your CA might cause the system to try to feed too much current back to the battery. Once mine's in a position to work on properly, I plan to upgrade the rectifier to a reg/rect set-up to prevent any possibility of overcharging. As for the lean running, it's probably worth having a look at the jets in the carb (esp. the main jet). If something's cracked, blocked or otherwise out of whack, you won't get enough fuel through and that might cause the trouble you're seeing. HTH Thanks HTH, I did some brushing up on rectifiers vs. regulators (I just replaced my diode board, rotor and regulator on my BMW R75/5 to fix a charging issue) - and believe I understand the functions. The rectifier seems like a diode board to convert AC to DC, but doesn't need/use a regulator - assuming that the power is not enough to cook the battery - so it doesn't need a regulator (correct me if I'm wrong). Hence the low charging rate. Going to test the stator and rectifier today. I suspect it's old so not performing at 100% but is doing its job...
And the carb is newly rebuilt - and it's definitely running lean - so will adjust the needle, up I think to make it richer...at idle it seems spot on (all according to plug appearance). regards, Chuck The charging system has no regulator, just a rectifier to convert ac to dc. The ignition switch engages extra coils in the alternator when turned to "light on" position.
The original selenium rectifiers are prone to failure with age so many just replace it with a bridge rectifier from Radio Shack or the like. https://www.radioshack.com/products/50v ... -rectifier Check the battery voltage before starting the bike. You need to let the engine run at speed long enough for the battery to recoup the charge lost from electric start before judging the charging system performance. Check the voltage after a run at speed for a better indication. 66 dream, 78 cb750k, 02fz1, 09 wing
The point I was making about putting a reg/rect in is that I have no idea what the maximum output of the charging system is, and so unless/until I'm sure the full output won't cook the battery, I'll rely on a device that can limit what goes back to the battery. I doubt those devices were added to later bikes without good reason for doing so, but that's just me.
If the running issue you're experiencing is a lean condition and it's only showing up under power, it points to something other than the idle circuit. You've got either two or three jets in the carb and only one circuit has any real influence over idle. So the chances are the idle will be spot on, but that has nothing to do with whether there's something wrong with one of the other jets, since they don't come into play until the bike is under power. The needle clip may help, but I'd be inclined to look and see whether you've got the right main jet size in place and/or that it's not blocked. I've rebuilt carbs before and had odd stuff happen - like the main jet falling out of place and into the carb bowl. That sort of thing can't be seen from the outside, but gives symptoms a bit like you've described. It's just one of many possibilities. Equally, I'd double check the float height and fuel path all the way from tank to engine. It's possible there's enough fuel getting into the system to idle and just about run the bike, but not enough to fully power it. If the bike's been sat for any length of time, make sure the fuel's good and that stuff like the petcock is clean inside. That's where I'd start. Incidentally, I thought Radio Shack had gone out of business. Shows what I know. HTH (hope that helps) Neil
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