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Chugging engine

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pompeybiker
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Chugging engine

Post by pompeybiker on Sun 15 Jan 2017, 12:31 pm

Hi Guys,

Got a question about my CBF500 (which has the same engine) I have only owned it for about a month and the engine seems to run ok and ticks over relatively smoothly, but I have noticed that if the engine revs are not perfect for the gear I'm in it is very prone to "chugging"/labouring.
I know it's a paralell twin and they are not as smooth and forgiving as a four but it does seem to be excessive, especially compared to my MT-07.
I was wondering whether the carbs need balancing? (it was an ex-courier bike with 80,000 miles on the clock and has been pretty neglected)
Any advice would be most welcome! Smile
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Fair Weather Rider
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Re: Chugging engine

Post by Fair Weather Rider on Sun 15 Jan 2017, 12:51 pm

I would look at fuel first, may be a bit lean.

Mike.
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pompeybiker
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Re: Chugging engine

Post by pompeybiker on Sun 15 Jan 2017, 1:19 pm

@Fair Weather Rider wrote:I would look at fuel first, may be a bit lean.

Mike.

Already looked at the plugs and they look a nice brown colour so probably not that
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Beresford
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Re: Chugging engine

Post by Beresford on Sun 15 Jan 2017, 2:00 pm

I think that you have already given the answer. You have said that when you get the gearing wrong and when you compare it with an MT07.

The Honda weighs about the same as the Yamaha (173 - 179kg) but is a lot less powerful (57-74bhp) and has a lot less torque (35-50ft-lb)
The Honda cannot run as smoothly as the Yamaha unless the revs are in the torque 'comfort zone'
So just keep the revs up !!! Very Happy
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Jameshambleton
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Re: Chugging engine

Post by Jameshambleton on Sun 15 Jan 2017, 4:15 pm

Chain tension has a massive part in this, get it spot on and it's perfect get it slightly off and you're screwed
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Vardypeeps
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Re: Chugging engine

Post by Vardypeeps on Mon 16 Jan 2017, 12:39 pm

Might be running a little rough at idle - See carb balancing
A lot of chugging can also be blamed on a loose drive chain or one with a tight spot in it
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pompeybiker
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Re: Chugging engine

Post by pompeybiker on Mon 16 Jan 2017, 10:54 pm

@Vardypeeps wrote:Might be running a little rough at idle - See carb balancing
A lot of chugging can also be blamed on a loose drive chain or one with a tight spot in it

I was wondering about getting some dial gauges for balancing the carbs.
It's got a new chan and sprockets fitted and the tension is fine.
Thanks
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Vardypeeps
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Re: Chugging engine

Post by Vardypeeps on Tue 17 Jan 2017, 10:36 am

Definatly get some if you don't have any already and get a kit with 4 dials in case you change bikes Wink

Tip when balancing the carbs if you get it warm with the tank on then remove it you can normally balance them with the fuel left over instead of fitting an alternate fuel supply.

Mine is running rough on idle and is fine as soon as the revs pick up, due a balance and proper carb clean.
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eternally_troubled
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Re: Chugging engine

Post by eternally_troubled on Wed 18 Jan 2017, 8:53 am

All the above are good suggestions for making it smoother, however I tend to agree with Beresford.

What revs are you getting 'chugging' at?

I don't know about anyone else but my CB500 doesn't go much below 4k rpm - certainly if you are going much below 3.5k - 3k rpm then that is into the 'chugging' area - just don't go there!

I know it's a paralell twin and they are not as smooth and forgiving as a four but it does seem to be excessive, especially compared to my MT-07.

It isn't an MT-07 Wink I think you've hit the answer on the head there - it isn't smooth and forgiving - more work with the gear lever may be required to achieve chug-free results!

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pompeybiker
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Re: Chugging engine

Post by pompeybiker on Thu 19 Jan 2017, 12:07 pm

@eternally_troubled wrote:All the above are good suggestions for making it smoother, however I tend to agree with Beresford.

What revs are you getting 'chugging' at?

I don't know about anyone else but my CB500 doesn't go much below 4k rpm - certainly if you are going much below 3.5k - 3k rpm then that is into the 'chugging' area - just don't go there!



I know it's a paralell twin and they are not as smooth and forgiving as a four but it does seem to be excessive, especially compared to my MT-07.



It isn't an MT-07 Wink  I think you've hit the answer on the head there - it isn't smooth and forgiving - more work with the gear lever may be required to achieve chug-free results!

I think you guys are probably right Smile
The Mt is very smooth for a twin and the Honda engine is a very old but reliable design and I should make allowances for that I suppose.
I will invest in some dial gauges to balance the carbs and probably give them a clean out too!

Thanks for your advice cheers
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eternally_troubled
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Re: Chugging engine

Post by eternally_troubled on Sun 22 Jan 2017, 2:00 pm

A carb balance is always worth doing if you can but it will only make a big difference if it is waaaay out. If it is *that* far out you can probably make it better without the gauges - just judge it by ear!

As a matter of interest I took a closer look at what revs I was using while riding along in a normal not-hooning way: I can confirm that below 4k isn't really a thing apart from when starting off from idle.
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ZekeVal
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Re: Chugging engine

Post by ZekeVal on Sun 22 Jan 2017, 4:46 pm

I've noticed some hesitations while purring along in 2nd in town at around 3-4k RPM, I'm getting better at smoothing this out but it still seems not normal and annoying at times.
Wondered if that was normal for you more seasoned riders?
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pompeybiker
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Re: Chugging engine

Post by pompeybiker on Mon 23 Jan 2017, 4:03 pm

@ZekeVal wrote:I've noticed some hesitations while purring along in 2nd in town at around 3-4k RPM, I'm getting better at smoothing this out but it still seems not normal and annoying at times.
Wondered if that was normal for you more seasoned riders?

I get that too Crying or Very sad
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eternally_troubled
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Re: Chugging engine

Post by eternally_troubled on Tue 24 Jan 2017, 8:11 am

@pompeybiker wrote:

@ZekeVal wrote:I've noticed some hesitations while purring along in 2nd in town at around 3-4k RPM, I'm getting better at smoothing this out but it still seems not normal and annoying at times.
Wondered if that was normal for you more seasoned riders?



I get that too :cry:


If mine does that the I haven't noticed :)  But then, as I said, when I actually looked at the rev counter the other day, I realised that I change gear to keep it between 4k and 6k most of the time without really thinking about it.

@ZekeVal - have you balanced your carbs?  If they need adjustment it can make these kind of problems worse.  Also, if you have an aftermarket exhaust it can make some 'hesitations' worse unless you've adjusted the jets (although this isn't always the case - it depends on the specifics of the exhaust).

@pompeybiker - If you are still unsure then the best thing to do would be to try and get a ride on someone elses CB500 and/or let them have a ride on yours - this will immediately tell you if yours is malfunctioning. I don't know if anyone else on here is near you (I assume you might be on the south coast!).
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Jameshambleton
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Re: Chugging engine

Post by Jameshambleton on Tue 24 Jan 2017, 9:14 am

I sometimes had this before when I didn't work the engine much as kept it at really low revs. Try hitting the red line in 1st and 2nd a few times for a few moments and maybe a 6+k rpm speed for about 10mins and it seemed to clearout my engine a bit and sent smoothly for a while longer.
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ZekeVal
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Re: Chugging engine

Post by ZekeVal on Tue 24 Jan 2017, 5:33 pm

Thanks for the suggestions, I'll explore in this direction.

I've had the bike for 4 month now, went from 74000km to 78000km.
I don't know when the carbs were last balanced, it might be a while.

Funny you mention the exhaust because I do have an aftermarket one, a LeoVince; and I was reading about the jetting issue on a thread here somewhere, where someone put 125 (is that 1.25mm?) jets with great success to cure a lean engine.
Since mine is really prone to "popping" - especially downhill in 3rd or 2nd when you have huge engine breaking - and tend to heat quickly even in those cold weathers, I suspect it to be lean. Not to mention the absolute necessity to use the choke first time I start it whatever the weather (and it was barely holding idle with full choke when I started it at -5°C as well). I guess I'll have to check the colour of my plugs to be sure.

Otherwise, I do hit the redline in 1st and 2nd (properly warmed up of course) at times when the road ahead allows it, but it doesn't seem to change anything.

Valentin.

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