3 into 1 exhaust jota

That Mez bloke was the bloke who did the porting on that Motodd Mark 5 race bike that Alan Cathcart won a world title on, Bath Tube style head. BTW that bike was for sale a little while ago.
 
Standard is 3-1-2 Exhaust. If you look for improved performance, different sound, lighter bike, tuned engine, a 3-2-1 can be an alternative.

you can check the net, there are several pics of 3-1 laverdas...
 
Building a performance 3 into 1 for a 180 degree engine is more difficult than 120 degree.
The problem is cylinders 1 and 3 , assuming everything is identical between the two , they are both trying to expel their exhaust gases at the same time. When the gases meet in the collector they will induce turbulence , consider two streams coming together, the water tends not to flow forward initially. Either the collector needs to be quite long to allow a merged connection of the down pipes or you could try coupling 1 and 2 down pipes together at the same point with no3 before or after.

Andy
 
KERMIT1200 said:
! and 3 fire at the same time.
Click to expand...
That would be VERY odd, Kermit (big bang motor gone wrong!). If it was a two-stroke, you'd be right, but on a 180 it would be 700-ish cc firing on one stroke and a 300-ish cc 180 degrees later!!
Uneven firing cycles is an issue I reckon affects my 270 motors as well. Some experimental work will reveal my best options ... but there are plenty of 270 twin motors running 2/1s ... an Aprilia performance exhaust has all sorts of extra plumbing linking different sections. And like big modern Dukes, they are high revving, short stroke motors - different kettle of sardines.
 
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The 180° engines fire on every turn of the engine (every 360°) on cylinder 1 and 3, but working cycles are 720°. So - if you look at the 180° cam (which rotates at 50% of the speed of the crank), you will soon understand that the outer two are 360° appart from each other in terms of working cycle, as the cams are pointing 180°in different directions (this times 2 = 360°). Cylinder no 2 (center) is 90° appart from one and 270° appart from the other. Times 2 = 180° or 540°).

180° Laverda triples work like a 4 cylinder engine with one of the center cylinders removed. simple as that. Just like Red says: 3-2-1-miss (while miss would be the 4th cylinder on an 4 cylinder engine)
 
I had an interesting chat about this at one of the Oz Bellangen rallys with someone who knows way more than me about 180 triple engine timing. I was way wrong and learned a lot. It's a lot more complicated than I thought at the time.
 
"The problem is cylinders 1 and 3 , assuming everything is identical between the two , they are both trying to expel their exhaust gases at the same time."

you have already admitted to being corrected Andy, but to cut all the tech info, on a 180 when the outer pistons are at TDC one is alight (say the left) and about to power the piston down, the other (say right) is just finishing puffing the exhaust out.

Next rotation this is reversed
 
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