Exhaust balance.

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Oily
Posts: 19
Joined: Mon Oct 01, 2018 6:09 pm
Location: Jersey

Exhaust balance.

Post by Oily » Mon Dec 30, 2019 5:02 pm

I have no balance pipe between my exhausts and Alan did say that it would make the engine run a bit smoother if I fitted one. It would be quite easy to fit one between the inlet manifolds, would this do the same job?

Seasons greetings to all!!

Oily.

Doverhay
Posts: 186
Joined: Thu Sep 27, 2018 6:43 pm
Location: TA66NN

Re: Exhaust balance.

Post by Doverhay » Mon Dec 30, 2019 5:49 pm

Did you really mean between the “INLET” manifolds?

Oily
Posts: 19
Joined: Mon Oct 01, 2018 6:09 pm
Location: Jersey

Re: Exhaust balance.

Post by Oily » Mon Dec 30, 2019 6:33 pm

Doverhay wrote:
Mon Dec 30, 2019 5:49 pm
Did you really mean between the “INLET” manifolds?
yes!

Doverhay
Posts: 186
Joined: Thu Sep 27, 2018 6:43 pm
Location: TA66NN

Re: Exhaust balance.

Post by Doverhay » Mon Dec 30, 2019 7:45 pm

It might be easier but the result wouldn’t be the same, in fact, quite the opposite 🥴

westendguzzi
Posts: 325
Joined: Tue Sep 25, 2018 7:30 pm
Location: Huntingdonshire

Re: Exhaust balance.

Post by westendguzzi » Mon Dec 30, 2019 8:03 pm

Eyup.
Why call this thread 'Exhaust balance' when you are talking of linking the inlet manifolds?
It seems to have been the custom with a lot of V twin engines to have a balance pipe between the exhaust pipes, not too far from the manifold. The theory being to introduce reverse pressure to the opposing cylinder thus getting the engine to run a bit smoother.
It's a kind of magic.
I removed my Triking exhaust balance pipe as it was the first point of contact with the road and kept getting damaged.
This did introduce minor problem with a flat spot around 2500rpm.
Short story, the whole exhaust pipe was out of tune, being too long from manifold to silencer and fresh air. I overcame this with the introduction of an 'in pipe' baffle at the end of the header pipe, before the long side pipe.
It has taken me several years to get Edith running as sweetly as she does now, pulling well right through the rev range. Went through lengthy trials will twin choke Webber carb but went back to my original spec with Delortos.
If you can get a 500 single tuned to perfection, why not 2 500 singles?
Makes more sense to me than linking out of sync cylinders.
Happy 2020 to all.

Doverhay
Posts: 186
Joined: Thu Sep 27, 2018 6:43 pm
Location: TA66NN

Re: Exhaust balance.

Post by Doverhay » Mon Dec 30, 2019 8:26 pm

Hi Tony, recently carried out this mod on my Weber DCOE (see pic) fitted a 130 main jet and a 50f8 idle jet and the engine now seems to run perfectly. The length of the inlet manifold still makes the throttle response a little lazy but the engine torque is quite good.
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Alanla
Posts: 24
Joined: Sun Feb 10, 2019 6:18 pm
Location: UK

Re: Exhaust balance.

Post by Alanla » Sat Jan 04, 2020 6:52 pm

Hi All

Any kind of balance between the INLETS will be detrimental on your (Carb) engine, or at best make it even more difficult to adjust the mixture. There have been a few Guzzi models with a very small (3mm bore) balance pipe between the inlets but they were controlled with electronic management, and fitted in conjunction / control with a specific ignition system. Due to the firing order of the cylinders the induction system needs to be (almost) separate for each cylinder- This is why Guzzi have always had separate carbs rather than a single carb, If Guzzi could have got the same performance result with just the cost of one carb they would have done so by now, An exhaust balance pipe changes the back pressure slightly and smooths out a typical engine at low to medium RPM, (The balance pipe has very little to no effect at the upper half of the RPM range, Hence they are not usually fitted to any high performance or race engines) This assumes that the engine is fairly std and correctly set up, if there are other variables like different size carbs, camshaft, valves etc the effect of an exhaust balance pipe will be negligible, (but not do any harm), Essentially a balance pipe will not "refine" an incorrectly set up engine. If a balance pipe cannot easily be fitted in the normal "Triking" position it can be fitted across the front of the header pipes as on the early Guzzi models - but it will need a slip joint due to the expansion / contraction.

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