Carbtune balancer

[Mac One]

Hello
Does anyone use the twin carbtune balancer (the one with the solid bars) for throttle balance....and do you find it accurate?

I've used one for around seven years now and i've got to say i find at a bit hit and miss, the bars seem to react differently when i blip the throttle, then they level out.

When i hold steady revs one bar will be higher, then they'll level out. Should they both move in unison all the time?

I've tried it with the GS911 parking the idle actuators an i've tried unplugging them but to be honest it doesn't seem to make much difference.

The bike goes well enough but i always wonder if it could go better if i got them spot on. Is there a foolproof method of setting them.

Cheers.

 

[Hoff]

Been using the twin Carbtune for about three years now and have never had any problem when balancing throttle bodies.
The only thing that comes to mind is do you have the restrictors fitted and are they nearest to the throttle bodies (sorry if I am stating the obvious)?

 

[UturnTony]

I use the Carbtune and yes, it can take a bit of effort to get it right but it usually comes good;
if it doesn't, it's likely there will be another factor affecting the running of the engine that needs attention.

 

[Mac One]

Been using the twin Carbtune for about three years now and have never had any problem when balancing throttle bodies.
The only thing that comes to mind is do you have the restrictors fitted and are they nearest to the throttle bodies (sorry if I am stating the obvious)?

I have the restrictors fitted as per instructions, don't worry about stating the obvious.....I'm prone to missing obvious things.

 

[Mac One]

I use the Carbtune and yes, it can take a bit of effort to get it right but it usually comes good;
if it doesn't, it's likely there will be another factor affecting the running of the engine that needs attention.

Cheers....Maybe I need to try harder....I admit it's not my favourite task, all that revving, the bike overheating, so i don't usually dwell on it.

 

[fink]

Been using my carbtune for over 25 years. Great bit of kit far better than gauges.
Make sure the tubes are vertical. Ensure that there is a good seal on the takeoff ports and the restricted side must be closest to the takeoff point.
Another thing to watch as the tubes get older the sidewalls get softer so can pinch.

 

[Pukmeister]

I find my carbtune very useful to get throttle balance in the ballpark, then switch to a Harmonizer for really sensitive fine tuning.

(I find the actual range of adjustment is huge but with a very narrow proportional band hence the above. If I start with the Harmonizer alone I can overshoot and end up getting lost).

 

[Bendy toy]

I bought a TwinMax at a classic car show only to find them panned by many users. But I find it works well. Start on a wide range then increase sensitivity until it's balanced. A final check with the vac tubes swapped left/right confirms its all ok.

 

[Mac One]

Thanks all
It would seem trial and error along with perseverance is the way to go....I had thought about the twinmax but from what i read in your reply Bendy, i don't think i'd be any better off.

I don't think you can buy the Harmonizer new, any more, and if Pukmiester has to use both it, and the Carbtune, then there's not much chance of me having much success with that either.

From Fink's reply, i just lay the Carbtune on the seat at about 45 degrees.....I will make sure it's vertical the next time

 

[UturnTony]

Thanks all
It would seem trial and error along with perseverance is the way to go....I had thought about the twinmax but from what i read in your reply Bendy, i don't think i'd be any better off.

I don't think you can buy the Harmonizer new, any more, and if Pukmiester has to use both it, and the Carbtune, then there's not much chance of me having much success with that either.

From Fink's reply, i just lay the Carbtune on the seat at about 45 degrees.....I will make sure it's vertical the next time

I hang mine from the handlebar using the zip tie type strap provided.

 

[Pukmeister]

You dont HAVE to use the carbtune before harmonizer, I just find that its simple and obvious analogue reading gets things very close easily and quickly (coarse tuning if you like.) I could fine tune further with the carbtune, but..........

The slight stiction of the carbtune sliding tubes is not as accurate as the harmonizer for fine tuning at idle so I switch to that and make tiny tweaks and throttle blips to get things as smooth as possible both at idle and revs.

The Harmonizers left-right bar screen and rpm display means you don't have to keep checking the bikes instruments, just make tiny adjustments then watch and rev it whilst noting left/right balance and rpm.

The difference between a balanced and unbalanced engine is night and day.

 

[Mac One]

You dont HAVE to use the carbtune before harmonizer, I just find that its simple and obvious analogue reading gets things very close easily and quickly (coarse tuning if you like.) I could fine tune further with the carbtune, but..........

The slight stiction of the carbtune sliding tubes is not as accurate as the harmonizer for fine tuning at idle so I switch to that and make tiny tweaks and throttle blips to get things as smooth as possible both at idle and revs.

The Harmonizers left-right bar screen and rpm display means you don't have to keep checking the bikes instruments, just make tiny adjustments then watch and rev it whilst noting left/right balance and rpm.

The difference between a balanced and unbalanced engine is night and day.

Hi there.... Apologies I should have said chooses to use both. The point i was making was that i'm not even getting a decent result with the Carbtune, so going to a more sophisticated balancer would not be of benefit to me, unless it could do it for me.

You say you fine tune your bike at idle, i have been syncing mine at 3,500 rpm and then locking off the adjuster at that.

I think i may have to start again from scratch with mine....I was out today to test it and it's holding back and popping (more than usual) on the overrun.

I'll let you know how it goes.

 

[Hoff]

I followed the procedure in Jim Von Baden`s DVD when doing this the first time and IIRC it is stated that there is no adjustment at idle (I use the GS911 to park the idle actuators) and the sync of the throttle bodies is done at 3500-4000RPM.
If I have misread something then apologies!

 

[mikeyboy]

I followed the procedure in Jim Von Baden`s DVD when doing this the first time and IIRC it is stated that there is no adjustment at idle (I use the GS911 to park the idle actuators) and the sync of the throttle bodies is done at 3500-4000RPM.
If I have misread something then apologies!

There is no idle adjustments
The tb are factory set ,mess at you’re own peril.
The only adjustment to be made is with the cable setting,in my opinion the part you guys are interested in is the take up balance.
A badly balanced bike will show at cable take up,so as you move throttle from rest,you look fora dip in vac.
That’s the one opening,so keeping 1 mm of play in the cables,adjust the cables to keep vac readings the same.
It’s at that point of fine control.that a bigtwin needs to be right,otherwise it will stutter and be a pain.
Beyond cable take up,you can’t adjust anything any way so what difference does looking at the balance make?

 

[Mac One]

There is no idle adjustments
The tb are factory set ,mess at you’re own peril.
The only adjustment to be made is with the cable setting,in my opinion the part you guys are interested in is the take up balance.
A badly balanced bike will show at cable take up,so as you move throttle from rest,you look fora dip in vac.
That’s the one opening,so keeping 1 mm of play in the cables,adjust the cables to keep vac readings the same.
It’s at that point of fine control.that a bigtwin needs to be right,otherwise it will stutter and be a pain.
Beyond cable take up,you can’t adjust anything any way so what difference does looking at the balance make?

That makes perfect sense.....Just on the take up is exactly when mines shows the biggest difference on the carbtune. I'll reset the cable free play and start again.

Many Thanks

 

[Bendy toy]

Mine stutters at town speeds when the balance is out and as Mike says it’s a pain. But at higher speeds a slight imbalance causes no problems.

Uneven tick-over will be idle stepper motors.

 

[Mac One]

Balanced the TBs this morning.... Concentrated on the take up as they start to open. The difference is like night and day, there's no popping on the overrun, the bike actually starts easier,(there was a hesitation before, like it was kicking back) the gear change is slicker (it had became clunky), it's a lot quieter, and it's pulling like a train. I'm delighted with the improvement.

Thanks again everybody for taking the time to reply.

 

[andeebee]

Need to do this.
Given you arent recommended on running these bikes stationary for long periods - what is the average time I should consider running the bike for whilst learning the balancing process?
Would running a fan in front of the bike help? - then I can pretend Im in a dyno room

 

[mikeyboy]

With a bit of practice it takes a minute or two
You are not holding a fast idle,merely gently blipping to see the take up balance
Once the cable clearance has been checked you are only adjusting one cable,I suggest getting into the habit of adjusting the rhs.
If it gets hot,turn it off.

 

[Steptoe]

There is no idle adjustments
The tb are factory set ,mess at you’re own peril.
The only adjustment to be made is with the cable setting,in my opinion the part you guys are interested in is the take up balance.
A badly balanced bike will show at cable take up,so as you move throttle from rest,you look fora dip in vac.
That’s the one opening,so keeping 1 mm of play in the cables,adjust the cables to keep vac readings the same.
It’s at that point of fine control.that a bigtwin needs to be right,otherwise it will stutter and be a pain.
Beyond cable take up,you can’t adjust anything any way so what difference does looking at the balance make?

Spot on ... I don't rev the engine above 2k revs when adjusting the cables, just during the pick up, you can almost adjust it by ear and feel then do the final tweek on the Harmoniser ..