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View Full Version : Carb balance - why all the fancy tools?



Mike.Gayner
17th March 2015, 20:01
Carb synchronisation seems to be one of those things that a lot of people leave to the shop because of the apparent need to specialised tools - vacuum gauge or manometer. I balanced the carbs tonight on my GSX in pairs using just a $2 piece of clear tube and some oil.

Shit pictures:
Hooked up - the air bubbles dissipated immediately upon starting the bike (http://i.imgur.com/hK5Dmjk.jpg)

Running - this pair were spot on, didnt need any adjustment (http://i.imgur.com/243Frl0.jpg)

All up the process took about half an hour, and only minor adjustments were necessary. This method is more accurate than a set of Chinese gauges - you can't fool physics.

tri boy
17th March 2015, 21:05
This method is more accurate than a set of Chinese gauges - you can't fool physics.

Chinese gauges maybe, but not as good/accurate as quality mercury filled manos.
The dampening and smooth flow of the mercury is the winner.
Mine are 30yrs old and work as if they were bought last week.
The long tubes, (1mtr) also are an advantage over the more compact design.

But yes, simple oil damped ones beat gauges every time.

nzspokes
17th March 2015, 21:57
Ive got a Carbtune. Easy and fast.

Drew
17th March 2015, 22:00
Piece of rubber hose, one end held at a fixed point on the bellmouth, the other held to your ear. When they sound the same, the throttle is set.

roogazza
27th March 2015, 11:18
Piece of rubber hose, one end held at a fixed point on the bellmouth, the other held to your ear. When they sound the same, the throttle is set.

Old school bud !
I was doing that stuff with Jaguars in the sixties,had some great teachers.
Twin SUs and Triples on the "E" Types.
There were vacuum type gadgets with floating bubble thingys but I went the "Hose" method. :cool:

Drew
27th March 2015, 22:01
Old school bud !
I was doing that stuff with Jaguars in the sixties,had some great teachers.
Twin SUs and Triples on the "E" Types.
There were vacuum type gadgets with floating bubble thingys but I went the "Hose" method. :cool:

Same as eyeballing a straight edge. The accuracy is remarkable.

It is the only way to properly balance a six pack Charger I'm told...and even then it has to be done with the engine loaded. So if ya don't got a dyno, you take the bonnet off and sit on the guard while the car is being driven.

ducatilover
28th March 2015, 12:31
I built a manometer for doing awkward carbs, otherwise the tube is fastest and accurate.
Fuck vacuum gauges.

ruaphu
29th March 2015, 07:42
Another vote for the carbtune gear. Brilliant tool, easy to use, cheap enough, and accurate as.


Sent from my iPhone using Tapatalk

Drew
29th March 2015, 10:50
Another vote for the carbtune gear. Brilliant tool, easy to use, cheap enough, and accurate as.


Sent from my iPhone using Tapatalk

This thread has been taken over, we don't care about your fancy tools.

tri boy
29th March 2015, 11:45
This thread has been taken over, we don't care about your fancy tools.

"I have accute hearing"

"I don't care about your jewelry old man.........................."

Reubix
23rd May 2015, 20:32
Carb synchronisation seems to be one of those things that a lot of people leave to the shop because of the apparent need to specialised tools - vacuum gauge or manometer. I balanced the carbs tonight on my GSX in pairs using just a $2 piece of clear tube and some oil.

Shit pictures:
Hooked up - the air bubbles dissipated immediately upon starting the bike (http://i.imgur.com/hK5Dmjk.jpg)

Running - this pair were spot on, didnt need any adjustment (http://i.imgur.com/243Frl0.jpg)

All up the process took about half an hour, and only minor adjustments were necessary. This method is more accurate than a set of Chinese gauges - you can't fool physics.


Ok, so how do you do it?

Mike.Gayner
23rd May 2015, 21:25
Ok, so how do you do it?

Same process as using vacuum gauges or manometer, but do the carbs in pairs as per your workshop manual.

ducatilover
24th May 2015, 21:34
A tube with oil is a manometer

Drew
25th May 2015, 08:36
A tube with oil is a manometer

It's hard to mark and lable the tube when your tuning a 4 pot though.

ducatilover
25th May 2015, 20:30
It's hard to mark and lable the tube when your tuning a 4 pot though.

Touche. Mine works chur as