balancing the carbs

[outlaw]

hi all, and a happy new year,
Can any one please tell me when balancing the carbs if it is more imporant to get the neddles ( i have the round dial type gauges ) all the same, as at the moe, i have set them all on 8,and it is very smooth on tick over at 1000, and very smooth on pick up, and running. but in the kawasaki manual it say,s if any gauge reads less than 15 cmhg it needs to be re adjusted, also what does engine vacuum 20-28 cmhg mean?
THANKS
JOHN
RIDE SAFE,

[floydsz1]

The reading given in the manual will change slightly anyhow as the engine wears. As long as the jetting/pipes etc are standard, then as long as the gauges are the same all will be ok. If it has a different exhaust then you may have to re-jet it.
Like i said the most important thing is to get them all the same.

[outlaw]

ok thank very much, as it is running smooth i will leave it as it is,

[jimmock]

Hi Outlaw,

Floydsz1 said it all.

The only addition I can offer is the cmhg. This means centimeters of mercury. It is a unit of measurement for a vacuum. inhg is inches of mercury. A perfect vacuum at sea level is "almost" 30 inches tall (76 cm).

Jimmock.

[m1ks]

Only bit of info to add is check and adjust mixture so that all cylinders are running on a good fuel air ratio, (use a Gunson colourtune, easy to use), then re-balance, as said, don't worry over specific numbers, just get them balanced together, 1 and 2, 3 and 4 then 1,2 and 3,4.

[wayno]

dont want to hijack this thread but as it has been mentioned about jetting/pipes, how do you decide what jets to use with different pipes? i only ask as i am waiting for a piper style from exhaust craft and may need to re jet.

thanks wayne

[Pigford]

Wayno - the above related to pipes & jets for the VACUUM GAUGES, not the carbs on the bike

[m1ks]

General rule of thumb is when you fit a freer flowing exhaust, (changing from the heavily baffled stock item only mind), you would increase the mainjet by roughly 10%, if you also fit pod filters go another 10%.
These are only rough rules and tuning carbs can really get convoluted, you can even get different tapered needles to alter fuel mapping throughout the range, (and not an ECU in sight).
If you're really serious about getting it set right then the best way is to take to a tuners and have it run on a dyno so the correct combination of jet / needle etc can be ascertained.

However, first things, stick on your new exhaust, start and run to operating temp, check mix with colourtune and adjust, if you can get it burning correctly just by adjustment of the air / fuel bleed then set and balance, if you're getting lean right through or it's 'just' in at the extremes then increase main and idle jet 10% and reset.
You can then arse around with needle tapers if you have any flat spots.

Hope this helps.

[wayno]

pigford. no need to SHOUT. newbie to this zed world and learning fast on this great site.