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running issue

Posted: Sat Aug 16, 2014 10:55 pm
by bshannon_1
I have an '83 Honda cb650sc nighthawk. I recently replaced the voltage rectifier with a new one and had the stator rebuilt. I aslo checked the battery and made sure it had a full charge on it. The battery is only a couple of months old. When I start the bike it runs fine at first but after a couple of minutes it shuts off as though one of the switches were turned to the off position even though they haven't been. After it quits the power is still on but when you depress the start button nothing happens. I then turn the ignition off and the kill switch to the off position. after a few minutes I power the bike back up hit the start button and the bike starts runs for a couple of minutes the shuts off again. Does anyone have an idea what the problem is, for I'm at my whits end. you can respond to my email address: bshannon_1@netzero.net

Re: running issue

Posted: Mon Aug 18, 2014 10:03 am
by GS_in_CO
sounds like the battery isn't holding a charge. (but I'm not going to email the answer)

Re: running issue

Posted: Mon Aug 18, 2014 7:45 pm
by Johnj
"SOMETHING" is getting HOT and shutting down. Like a regulator or a rectifier. Try using your hand to see which is hot.

Re: running issue

Posted: Tue Aug 19, 2014 1:43 pm
by bshannon_1
No, the rectifier is not even warm and is brand new as well as the stator. Moreover, the bike will not run long enough to even get to operating temp.

Re: running issue

Posted: Tue Aug 19, 2014 2:16 pm
by GS_in_CO
Are you charging the battery before attempting to run the bike?
Are you monitoring the voltage on the battery as it runs?

Since you replaced voltage regulation/generating parts before this problem..... chances are real good that the two are related.

I should add that the battery could have been damaged by leaving it discharged for several months if the reason it sat idle was because of the charging system not working. lead-acid batteries really, really, really don't take well to staying discharged.

Re: running issue

Posted: Tue Aug 19, 2014 5:06 pm
by bshannon_1
No, I've kept the battery charged, and I'm not sure if it is getting charged due to the fact that the bike will not stay running long enough to test it. It will only run for A minute or two. However, I feel that the battery has continued to keep a charge since it has not been drained.

Re: running issue

Posted: Tue Aug 19, 2014 7:28 pm
by BRUMBEAR
hmmm that sounds like it could be the new stator heating up and shorting but the main power fuse should blow you don't have one of the circuit breaker style fuses in there do ya?

Re: running issue

Posted: Tue Aug 19, 2014 8:34 pm
by GS_in_CO
Well - there's still the classic plugged fuel tank vent so that the fuel isn't flowing quickly enough into the carbs....
Or plugged petcock strainer, or contaminated fuel in the carb bowl so there isn't enough good fuel to run for long....

Re: running issue

Posted: Thu Aug 21, 2014 10:36 am
by dr_bar
I'm going to say it has to do with the rectifier/ regulator. Possibly faulty, it sounds like there is no charge going to the battery and the engine is running off the battery instead of the stator, which would be why the battery drops dead so quick...

Re: running issue

Posted: Thu Aug 21, 2014 11:29 am
by GS_in_CO
dr_bar wrote:I'm going to say it has to do with the rectifier/ regulator. Possibly faulty, it sounds like there is no charge going to the battery and the engine is running off the battery instead of the stator, which would be why the battery drops dead so quick...
The duration of the run seems too short for this to be the case unless the battery has no capacity.
(BTW- the charging system doesn't carry the load when at idle on most bikes - the battery does.)

But a way to double-stick it - other than using the correct tool for the job (a voltmeter) - might be to disconnect the headlight so as to reduce the electrical load while running.


On the other hand- I once stored my XT350 with an additional Marvel Mystery Oil in the gasoline.
During the storage period the oil separated and went to the bottom of the tank. At restart time it would only run a short time. There was oil instead of gas in the carb bowl. Draining the bowl fixed the problem. That's probably not the case here but odd things can happen.

Re: running issue

Posted: Thu Aug 21, 2014 11:58 am
by GS_in_CO
Oh- there's also the 'vibrating loose connection' possibility. Ground for ignition coming undone?

Re: running issue

Posted: Sat Aug 23, 2014 9:42 am
by bshannon_1
Ok. I stick the vent and it is not clogged. I do have a clear in-line fuel filter and in watching the flow it's more than adequate. I do use fuel stabilizer when I know I will not be ridding for a given period or going to store it for the winter. So the fuel is good. I am leaning towards the stator possibly having a short, and the correct line of thinking is that it would blow the fuse. I have checked all the fuses and there good and even tried replacing them with new ones in case there is a micro break. I'm going to try cleaning the emergency stop switch and the start button in case there is any corrosion that could cause the problem. I am also putting the original wiring harness back in to eliminate the possibility of a nick in one of the lines that could cause a short. Again I have checked the battery and it is holding a charge. I will update when I gat these things done. Thank you to all.