Carb balancing – experimentation after theorising

[Blue_SV650S]

Ok, so I see numerous posts where people recommend getting the carbs balanced at the slightest sign of engine insurrection - virtually any symptom somone says get the carbs balanced … I have always though ‘like how is that gonna help here?!?!’ … but as it is a ‘good’ thing to do, never said out …

That said, I did bite the other week where someone was claiming they felt large performance gains after doing carbs … at that I bit and proceeded to state why I felt that was theoretically nonsense.

Anyhoo, I balanced my carbs the other day 8) … they were about 14cmHg out – which is about 2/3 of my gauges range, so a fair bit … :o

And guess what the ‘difference’ was after setting them to within 0.5cmHg? :?

Did I now own a fire breathing granny exploding monster that wants to flip me over the back every time I twist the tube??? :smt047

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NO!! :D

[Scoobs]

Bet it felt a lot smoother though.

[dirtydog]

:rolleyes::rolleyes::rolleyes:

oh here we go again :nomore::nomore:

[Blue_SV650S]

Bet it felt a lot smoother though.

It idles nice and smooth now, which I expected to be the result, so that is 8) ... but at anything over minimal throttle openings on the move and absolutely NO discernable difference, which again I am in no way surprised by .. .

[johnnyrod]

It partly depend son whihc way it was out - this gets a bit hocus pocus but my exxperience of twins is that say it was out by 0.1bar one way it'd be utter crap, but 0.1bar the other way and it'd run more or less fine. Somethig to do with the uneven gaps between the two cylinders firing. Nevertheless, it's a job worth doing.

[Sid Squid]

Ok, so I see numerous posts where people recommend getting the carbs balanced at the slightest sign of engine insurrection - virtually any symptom somone says get the carbs balanced … I have always though ‘like how is that gonna help here?!?!’ … but as it is a ‘good’ thing to do, never said out … You're right of course - someone will recommend carb balancing when it doesn't handle right or the brakes don't work very well. See 'Tip' below.
That said, I did bite the other week where someone was claiming they felt large performance gains after doing carbs … at that I bit and proceeded to state why I felt that was theoretically nonsense.It's not nonsense, if it's out then performance will be lost - this isn't in question - how much is lost, that's the question, (answer - overall very little. But you were talking theoretically, and that's a definitive answer, end of.)
Anyhoo, I balanced my carbs the other day 8) … they were about 14cmHg out – which is about 2/3 of my gauges range, so a fair bit … :o
And guess what the ‘difference’ was after setting them to within 0.5cmHg? :?.Well assuming that you connected the gauges correctly and there weren't vacuum leaks, as that difference in vacuum on a bike that ticks over at all would make me look there first, and also assuming you've got everything else set right of course* I'd say it ticks over rather better, low speed pickup is better, and low end throttle transitions are a lot easier.

Did I now own a fire breathing granny exploding monster that wants to flip me over the back every time I twist the tube??? :smt047..

NO!! :D
And did you think it would? Did anyone on here who knows what they're talking about suggest it would? (Refer to 'Tip' again). As has been stated previously, balance at anything other than low revs is irrelevant, this is obviously where the smallest change make the largest difference as any given amount of variance is the largest degree of difference. So overall your lack of detection of the huge performance enhancement that others have found is entirely unsurprising. But then some people's bikes will do 140mph when the air intake snorkel is removed, and their suspension gets harder when they increase the preload too.


* I'm sure you're aware that balancing the carbs is the very last job you'd do after all other relevant servicing tasks - valve clearances, plugs etc. All of which have an effect on balance.
Tip: Not everyone on here gives good advice, I hope you know this - I'm sure you do.

[Stig]

You're right of course - someone will recommend carb balancing when it doesn't handle right or the brakes don't work very well. See 'Tip' below.
It's not nonsense, if it's out then performance will be lost - this isn't in question - how much is lost, that's the question, (answer - overall very little. But you were talking theoretically, and that's a definitive answer, end of.)
Well assuming that you connected the gauges correctly and there weren't vacuum leaks, as that difference in vacuum on a bike that ticks over at all would make me look there first, and also assuming you've got everything else set right of course* I'd say it ticks over rather better, low speed pickup is better, and low end throttle transitions are a lot easier.


And did you think it would? Did anyone on here who knows what they're talking about suggest it would? (Refer to 'Tip' again). As has been stated previously, balance at anything other than low revs is irrelevant, this is obviously where the smallest change make the largest difference as any given amount of variance is the largest degree of difference. So overall your lack of detection of the huge performance enhancement that others have found is entirely unsurprising. But then some people's bikes will do 140mph when the air intake snorkel is removed, and their suspension gets harder when they increase the preload too.


* I'm sure you're aware that balancing the carbs is the very last job you'd do after all other relevant servicing tasks - valve clearances, plugs etc. All of which have an effect on balance.
Tip: Not everyone on here gives good advice, I hope you know this - I'm sure you do.

Ohhh you fibber