Honda Twins banner

1 - 4 of 4 Posts

·
Registered
Joined
·
28 Posts
Discussion Starter #1
So, originally my CB450 didn't seem to be charging all that great, I was lucky to get the voltage up to 13 VDC at the battery, in fact I don't think it even managed that. Since then, I had the voltage regulator off and changed the rectifier for a newer style one, and now the voltage climbs up steadily as it's revved. Put a new regulator on and it seemed to tame it a little but, but now I'm noticing that it can still climb as high as 15VDC at the battery.

I suppose both of the regulators could have been bad, since the new one was used as well. But I also want to ask if it's possible that high voltages can cause the engine to start skipping at high RPMs? Yesterday I rode my motorcycle for the first time and had no problem even at WOT over 6k, but today riding back from a longer trip I noticed that it would start cutting out at around 6 or 7K RPM, and I'm wondering if this could be causing the problem.
 

·
Registered
Joined
·
363 Posts
15 does not sound too excessive, I believe 14.7 is optimal. it's possible that the slightly high voltage is breaking down your coils but I'd bet your timing has shifted / advance is sticking or you're suffering from fuel starvation. what kind of voltage to you get with the headlight on?
 

·
Registered
Joined
·
28 Posts
Discussion Starter #3
I don't think it's a fuel starvation issue because it hasn't done it since, but I've only been going on short trips. I've yet to see if it'll do it again, I'll be going on a longer trip on saturday for my motorcycle skills test. I'll see how it behaves then if it repeats this.

The voltage was hitting 15 with or without the headlights on.

Is it still possible to get new coils for this bike? (just in case I end up needing some)
 

·
Registered
Joined
·
363 Posts
you probably won't find new old stock ones, and if you do they will likely be expensive and nearly 40 years old (both bad things). it is popular to modify the bracket to fit new coils like the items from mikes xs, (easy to do with a little ingenuity and common hand tools), costs will run you about 60 bucks depending on the path taken. do a search for ignition coils and it should come up.

As for the high voltage sounds like your battery or connections may be flaky, if it's sick then it may not be accepting the full charge current causing surplus power and a higher than normal voltage.


when you are testing with the ignition off, bike not running etc, what does the battery read? and just out of curiosity have you verified your multimeter as accurate? usually high voltage will make the bike run better (until it kills the coils) but if your lights are not burning out I just don't see the voltage as being that high..

lousy running after a while at high rpm does sound like weak coils (coil gets hot starts to fail, cools off and acts fine)

just for gee whiz though.. my bike was giving me fits at high load after it got hot, turned out it was vapor lock / under preforming gas tank vent bike would loose a cylinder and stumble all over itself, I'd get of and mess with it pop the cap but by then it was sucking air through the right carb drain up the hose and through the petcock to vent the tank, supper weird symptom, all I know is after a drilled another hole in the gas cap baffle it cleared right up.
 
1 - 4 of 4 Posts
Top