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Author Topic: CB500 - Not starting  (Read 1103 times)

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Offline hummbug

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CB500 - Not starting
« on: August 13, 2009, 02:40:29 AM »
1971 CB500 - in Australia - I've had the bike for a month...still learning it's ways.
I thought it was due for a start tonigh -it hasn't been done since Sunday and won't again for a few days. It's not firing at all and doesn't even sound close, kinda like it's out of fuel (it's not). All I'm getting is a little mumble from the pipe when I give a bit of throttle. I have tried choke and no-choke with no effect either way.

Last ride was on Sunday, I filled the tank but decided to try a higher octane fuel this time, just to see if it made a difference. I've been using regular but tried Octane 98 this time...could this be a factor? I rode it after filling it and it ran fine...in fact it was going strong.

Also (longshot) I have the seat off, getting re-upholstered...shouldn't make a difference...should it?

I was going to pull the plugs for a look but the light is blown in the shed and I have to take the missus out for dinner. Any thoughts from the brains trust before I manage to get into the shed and have a proper look?

Thanks!!  :)

« Last Edit: August 13, 2009, 02:50:09 AM by hummbug »
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Offline Lars

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Re: CB500 - Not starting
« Reply #1 on: August 13, 2009, 03:59:46 AM »
Well, either a fuel issue or an electrical issue. Long time not running and you are most likely looking at a carb cleaning job. Check if fuel is getting out of the petcock and if the spark plugs are wet after an attemt to start. If plugs are wet it indicates you get fuel, but still the carbs are likely to be the problem. If you get a good spark on all plugs, I would check points gap and timing.

You can also have a look at this site.

http://www.hondahobby.no/website.aspx?displayid=1736

Lars
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Offline hummbug

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Re: CB500 - Not starting
« Reply #2 on: August 13, 2009, 04:02:39 AM »
OK, so a bit more info might help. I've had the bike serviced, the carbs synced and the it was running well..except the fuel line was replaced and not tightened properly so I had a fuel leak. I fixed that and in the process took the petcock apart and checked it...all fine and working well.

I might try to charge the battery and see if that helps...
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Offline Hush

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Re: CB500 - Not starting
« Reply #3 on: August 13, 2009, 04:10:04 AM »
The change in octane rating wont hurt the bike, I'm supposed to run regular in my 650 but I find the new Vpower works pretty good too.
Kill switch is not in the "OFF" position?
Gas tap in the "ON" position?
Probably not but hey I've been caught before by that myself.
You haven't removed the plug caps and put them back on the wrong plugs, another easy mistake.
Check your points for clean contacts, points are the weak point on all old bikes, run a piece of non plasticated carb board (business cards are brilliant for this) through the points gap a few times.
Along with points of course goes the ever unreliable condensers, if in doubt replace as they are cheap and expendable.
As Lars suggested check the plugs for spark........get back to us with the results. :)
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I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline hummbug

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Re: CB500 - Not starting
« Reply #4 on: August 13, 2009, 04:19:48 AM »
Thanks for the suggestions. I am embarrassed but happy to report that in the dark shed I must have flipped the kill switch and not checked it...It started first time, like a charm, with a bit of cough and splutter from all my earlier attempts and flooding. I need to thank Two Tired because he gave a list of suggestions on another post which included the kill switch idea. But thank you Hush for backing it up...

I promise I will not make hasty posts now and check ALL the possibilities before coming on here with a wild goose chase.
Thanks again...
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Offline Hush

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Re: CB500 - Not starting
« Reply #5 on: August 13, 2009, 04:20:49 AM »
No worries dude, we all come here for help, glad your bike is working for ya.
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I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline Lars

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Re: CB500 - Not starting
« Reply #6 on: August 13, 2009, 04:21:39 AM »
Yes, battery can be the problem, but if you where running the starter you would know. If you where kickstarting you would not know
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