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[solved]Running Rough

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Fair Weather Rider
Running out of unique names
Running out of unique names

Posts : 171
Location : Tenbury Wells

[solved]Running Rough

Post by Fair Weather Rider on Thu 26 Jan 2017, 3:06 pm

Hi, the bike has been stored in my shed for over two months now, and I decided to start it up the other day and blow the cobwebs out, so to speak (Not going for a ride, just on the stand in garden)
The buggar wouldn't start, normally it goes first prod, did fire a couple of times and stopped again, couldn't understand what was wrong, so put battery back on charge and put bike back in shed.
Next day put battery back on, hit the starter button, bike turned over a few times, fired and stopped, after a few tries I got it to run, but it was running very rough and I was having to keep the revs up to keep it running. Ran it for about 10 mins and eventually got a smooth tick over.
Have started it up again today and have had the same problem, misfiring and running rough.
Question. Has anyone else had a similar problem?
               Is it because it's so cold?
               Is it the damp.
I have had plugs out and checked gaps
Can't remember my last CB being like this
But this one goes well when it's warm. Wish it was warmer, then I would give it some wellie up the road.
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eternally_troubled
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Location : 'ere be fens. (near Cambridge)

Re: [solved]Running Rough

Post by eternally_troubled on Thu 26 Jan 2017, 5:17 pm

The fact that the bike started to run fine once it had warmed up (as you said in your post) suggests to me that it was just the cold/lack of choke.

Did you use the choke? (I say 'choke' but it's actually an 'enrichment circuit' within the carbs that is susd to suck in extra fuel when activated).

We've found previously (on this forum) that different CB500s need different amounts of choke: some will start in all weathers with almost no choke and a few even need some choke in summer.

So, if you didn't have the choke on, put it on and try again!

If you *did* have the choke on then check that the cable and the choke mechanism (attached to the carbs) is moving correctly.

If it's not that then it could be that your coils or HT leads are unhappy due to damp - worth a good inspection to make sure the rubber isn't cracking on the leads and the coil terminals are secure/corrosion free. Might also be worth watching it running in the dark - makes it easier to see any sparks that are escaping.
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Vardypeeps
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Re: [solved]Running Rough

Post by Vardypeeps on Fri 27 Jan 2017, 12:34 pm

@Fair Weather Rider wrote:Hi, the bike has been stored in my shed for over two months now, and I decided to start it up the other day and blow the cobwebs out, so to speak (Not going for a ride, just on the stand in garden)
The buggar wouldn't start, normally it goes first prod, did fire a couple of times and stopped again, couldn't understand what was wrong, so put battery back on charge and put bike back in shed.
Next day put battery back on, hit the starter button, bike turned over a few times, fired and stopped, after a few tries I got it to run, but it was running very rough and I was having to keep the revs up to keep it running. Ran it for about 10 mins and eventually got a smooth tick over.
Have started it up again today and have had the same problem, misfiring and running rough.
Question. Has anyone else had a similar problem?
               Is it because it's so cold?
               Is it the damp.
I have had plugs out and checked gaps
Can't remember my last CB being like this
But this one goes well when it's warm. Wish it was warmer, then I would give it some wellie up the road.

Sounds like my issue under the coils and ht leads post. Moisture getting into the HT Leads/Coils/Plug Caps? Once it's warmed up the issue does in the shed but ridden out in moisture will bring it back.

Take a look around when it's running rough and see if you can spot the spark plug charge arching to the frame or engine?

Can be difficult to start on choke and has a really rough idle due to weak spark to one cylinder.

Keep us posted Smile
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Fair Weather Rider
Running out of unique names
Running out of unique names

Posts : 171
Location : Tenbury Wells

Re: [solved]Running Rough

Post by Fair Weather Rider on Sat 04 Feb 2017, 3:23 pm

Found the problem, have been starting it up regularly and it has still been running rough.
Weather was nice today, so got bike out of shed to warm it up, misfired popped and banged and eventually I got a reasonable tickover, threw my gear on quickly before bike went cold, jumped on it and fired off up the road, seemed a little sluggish not pulling very well couldn't get into top gear, even fith was a struggle, then it dawned on me, it was only running on one cylinder, I tried to screw more rev on to try to bring failing cylinder into life, but it was not going to have it, had done about 3 miles now, so turned and headed for home...........Felt the exhausts off side , red hot, near side cool..........Out with the spanners, tank off....near side plug out, held it on the frame and turned engine over, no spark, found some old plugs in shed (off my old CB so I new they were good) popped in new plug on near side and hey presto, it burst into life and sounded so sweet, quickly put it all back together and threw gear on again, the difference was amazing, the bike went really well.
Although I had checked plug gaps on my previous inspection, I hadn't checked for spark, because the bike had ridden ok when I bought it and the plugs looked brand new.
Moral of story, Never Assume...............Well pleased Tenbury Wells.
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eternally_troubled
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Re: [solved]Running Rough

Post by eternally_troubled on Tue 07 Feb 2017, 10:40 am

It's nice when it is an easy fix. Sadly the only way to completely avoid this problem is to change the spark plugs at regular intervals (Honda say 2 years or 16000 miles) - which personally I find wasteful, given they can often keep working for years and years longer than that.

On an somewhat divergent note: I have just fixed a similar problem on my car - it was running like shit on occasion and stopping sometimes: suffice to say it is amazing how much corrosion you can clean out of a distributor cap and from a rotor arm! (luckily not a problem the CB500 is going to have!)

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Re: [solved]Running Rough

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