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Discussion Starter · #1 ·
Looking to replace my current carb on a 1600TP as its one of the nasty Chinese knock off H30/31 from my now deceased 1300 (not a Brosol as advertised!)

Do the ITC's need a balance pipe? Any one run them without?

Cheers,

Alex
 

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I have no balance pipe on mine and it runs well and pick up and idle are both good.

You don't need the balance pipe if you set the carbs up correctly.

I own old school bikes so I am familiar with balancing carbs and I have the vacuum gauges to do the job properly.

I balanced mine at idle and on part throttle and they are fine.

The balance pipe really only compensates for a poor set up in the first place.
 

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It will run like a dog without one and be difficult to tune.

Usually the manifolds come already drilled and tapped ready for a half inch tube fitting to be fitted.
Not so. My 1641 had no balance pipe and once the throttles were synch'd she ran just fine and then after tuning the jets and emulsion tubes she sang even better and never gave me any issues.

This was with genuine Webers and not those cheap shite from Empi though ;)

for the OP - yes the balance pipe will help but if you use a flow gauge to set the idle screw and idle mixture then by ear it should run great :)
 

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Discussion Starter · #8 ·
for the OP - yes the balance pipe will help but if you use a flow gauge to set the idle screw and idle mixture then by ear it should run great :)
Interesting - thanks.

I already have the snail gauge from setting up the HPMX's on the van, so would balance this way.

The cost difference between Weber and Empi for the ITC type is only about £50, so I'm planning to go real Weber, probably with the CSP bell crank linkage.

none the wiser really as to whether I need the pipe as opinion seems rather split, will try without and retro fit if it runs like a dog!

Cheers all,

Alex
 

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The balance pipe isn't just to even out the pressures in the inlet manifold so they are equal. It also acts as a tuning aid to improve cylinder filling. In the same way that the exhaust needs to have equal primaries and secondaries the pulses can be fooled with the inclusion of a balance pipe between the two flows to ensure that the pulses hit the back of the valve with the high pressure part of the wave.

With a pair of ICTs I can imagine that the length of the balance pipe is both preset and probably too long for any great influence.
 

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Discussion Starter · #10 ·
With a pair of ICTs I can imagine that the length of the balance pipe is both preset and probably too long for any great influence.
Thanks - I spent some time last night looking at looking at some motorbike forums as carb balance pipes are discussed in great detail on them.

It would appear that they have sized (length and diameter) pipes which are all quite short, and changed (like jets) to give maximum performance. Looking at the lengths and sizes they use having a 1/2inch metre long pipe isn't likely to have the right effect on the ICT's.

I'll fit them without the pipe and see how it goes - its just one less place to generate a leak then!

Cheers,

Alex
 

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Interesting - thanks.

I already have the snail gauge from setting up the HPMX's on the van, so would balance this way.
Yup, disconnect both throttle linkages once she's running so you can set the carbs properly and then connect each link in turn whilst re-checking the flows stay the same. You'd be surprised how much being slightly the wrong length will change the throttle plates position.

Oh, and if you have a non-std cam then if she still runs rough the balance pipe may help smooth the cam over a bit.
 
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