carburettor balance pipe question

[moolfreet]

Hello,

I've been having a go at balancing the carburettors on my Sport but I don't seem to be having much success. I'm using a Morgan Carbtune connected to the holes in the manifolds after removing the little metal plugs.

I understand that the balance pipe between the carbs has to be removed to balance them but when I do this I get a stream of petrol all over the egnine!
Surely I must be doing something wrong.

Any tips gratefully received,

Nick

[neil]

Hi, I use a Morgan Carbtune but my bike has rubber manifolds and there are no plugs so I remove the balance pipe & connect the carbtune in it's place, never had any problem with petrol coming out. I thought the balance pipe was something to do with balancing the air pressure between the 2 carbs. Hopefully someone more knowledgeable will enlighten us!

[moolfreet]

Hi Neil,
Thanks for the reply - I tried that and got no movement whatsoever on the columns. There was plenty of petrol in the Carbtune tubes afterwards tho'.

I'm beginning to think the carburettors are suspect.
Did you do ok with the mixture screw? ie hearing the engine get faster or slower or 'stumble'?

Nick

[EVguru]

Hello,

I've been having a go at balancing the carburettors on my Sport but I don't seem to be having much success. I'm using a Morgan Carbtune connected to the holes in the manifolds after removing the little metal plugs.

I understand that the balance pipe between the carbs has to be removed to balance them but when I do this I get a stream of petrol all over the egnine!
Surely I must be doing something wrong.

Any tips gratefully received,

Nick

Umm, are you removing the balance pipe, or the fuel pipe between the carbs?

If a balance pipe is fitted, there are usually no vacuum take-off ports on the inlet manifolds and vice versa.

What year/version is your sport?

[moolfreet]

Umm, are you removing the balance pipe, or the fuel pipe between the carbs?

If a balance pipe is fitted, there are usually no vacuum take-off ports on the inlet manifolds and vice versa.

What year/version is your sport?

Ahh! Another triumph of my own ignorance - I'd thought that they were the same thing. Not very bright, that. The Sport is from 1978, alloy wheels, single front disc. There is the fuel pipe connecting the 2 carburettors but nothing else. I'll have another go at balancing.

Thanks for clearing that up for me.

Nick

[neil]

Hi Nick, looks like Paul has come up with the answer (knew he wouldn't let us down ) I always struggle with balancing the carbs, each time I think it's right I blip the throttle & when she settles down again the balance is out. I'm guessing it's because my carbs are worn & the slides are loose in the bodies. Hope you have more success!
Neil.

[EVguru]

Balance on the idle stops isn't as important as balance at 1/8-1/4 throttle. That's what really makes a difference to rideability and pickup.

I balance the cables first, then then the idle. A 'U' tube manometer between the carbs is the most accurate.

[3potjohn]

I use the trusty homemade device "the 4$ carb balancer" from the Airheads site. I may be doing this wrong for the Morini, but I get a balanced tickover using the throttle stop and idle screws,with the cables adjusted to give extra slack,then get adjust the cable adjusters to give minimum free play,watch the balance so you are avoiding lifting the slide by overdoing it,then open the throttles and if one is out of balance I adjust the cable to give even levels again. But this is my BMW method of course. All connections must be sound too.