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Has anyone tried running the 350 with 2 separate down pipes without an exhaust link pipe, is it there just to keep noise down or does it have an effect on power/torque ?

Its there to support the exhaust pipes. I have removed it from all my Morinis without problems as I prefer to keep the gases going in a straight line and each half the engine separate just like Doug Hele did on the Works Norton racing twins in the fifties and of course the Works Thruxton Bonnevilles and those who raced Vincents in the fifties/sixties and MV with theirs twins, threes, fours and sixes, plus Gelera plus Rondine et al.

I don't claim to know the answer to this, but when I first came to Morini ownership I noticed that although my bike had the link pipe, the hole had not been drilled on the right hand pipe, thus rendering it as two separate systems, a phone call to NLM confirmed that the bike was designed to run with a balance pipe and the advice was that I drill the hole, this I did, but I honestly did not notice any difference afterward.

Generally a balance pipe, particularly on a 'V' engine is primarily to make the exhaust quieter. They can boost torque in certain rev ranges, but often the position is chosen for mechanical packaging reasons and the torque boost doesn't happen where it would be of most benefit.

A seperate pair of equal (tuned) length pipes would be your 'race' exhaust.

EVguru wrote:Generally a balance pipe, particularly on a 'V' engine is primarily to make the exhaust quieter. They can boost torque in certain rev ranges, but often the position is chosen for mechanical packaging reasons and the torque boost doesn't happen where it would be of most benefit.

A seperate pair of equal (tuned) length pipes would be your 'race' exhaust.

forgive my ignorance but how can you have equal length pipes on a longitudinal V twin??? Front cylinder pipe is much longer than rear cyclinder. asuming silencers are also equal length......

EVguru wrote:Generally a balance pipe, particularly on a 'V' engine is primarily to make the exhaust quieter. They can boost torque in certain rev ranges, but often the position is chosen for mechanical packaging reasons and the torque boost doesn't happen where it would be of most benefit.

A seperate pair of equal (tuned) length pipes would be your 'race' exhaust.

forgive my ignorance but how can you have equal length pipes on a longitudinal V twin??? Front cylinder pipe is much longer than rear cyclinder. assuming silencers are also equal length......

Look at the Valentino or NLM racer. The rear pipe comes forward around the engine.... or, if you can, an Excalibur, which has a complicated setup with a U tube in front of the rear wheel.

Db7gtgrigio wrote:

EVguru wrote:Generally a balance pipe, particularly on a 'V' engine is primarily to make the exhaust quieter. They can boost torque in certain rev ranges, but often the position is chosen for mechanical packaging reasons and the torque boost doesn't happen where it would be of most benefit.

A seperate pair of equal (tuned) length pipes would be your 'race' exhaust.

forgive my ignorance but how can you have equal length pipes on a longitudinal V twin??? Front cylinder pipe is much longer than rear cyclinder. assuming silencers are also equal length......

Or you can use harmonics, and make the shorter pipe a harmonic length of the longer pipe.

If you have a 2 - 1 system, the pipe lengths are the same and have an extractor effect, if you leave the silencer off then both pipes are the same length and you can then lengthen or shorten to produce the torque where you want it in the rev range to suit the track you are competing at e.g. Cadwell long pipes, Brands Hatch short pipes, its what we used to do in the sixties then a mega was fitted for Snetterton.

In the case of Fridegotto there was this loop under the crankcase in order to equalize pipe lengths.

Like Db7gtgrigio I once queried that Morini 350 pipes aren't the same length however you measure them and I also didn't get an understandable reply.
Are they in fact not of equal length or am I, like Db7 somehow missing the point?

Guys;

See this thread; viewtopic.php?f=4&t=4153&p=20515&hilit= ... ths#p20515

Lambertinis' best air-cooled V was the the New York, in terms of torque and speed (no, I have nothing but memory to support that...) and it's worth studying the exhaust / silencer run on that...

Good riding,

CC

The measurements that follow are from 1975 350 Sport and 1975 350 Strada/GT bikes. Total length of front (right side) header pipe is approximately 94 cm. (That was the Sport; I didn't bother to measure the Strada/GT; it should be the same or pretty close.)

Total length of Sport rear (left side) header pipe is approx. 75 cm. Total length of Strada/GT rear (left side) header pipe is approx. 53 cm.

With the exhaust layout that Morini chose in 1975 there was no way they could get equal length headers.

Here's the left hand header of my '78 project Sport , imported from Italy: the pipe projects a loooong way into the silencer. For comparison I propped the original header from my other Sport next to it. Who knows who's been out there with hacksaws or extra bits of pipe?

both my 76-75 morini's have the pipe project into the silencer like this.
one of those had less than 10.000 km when i bought it ,was absolutely original , so that is how they came from the factory.