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Discussion Starter #1
I had always thought that the TL ignites at 0 and 180 degrees, but I read somewhere that it is actually 0 and 270 degrees. Does anyone know what the crank throw for the other V twins is? I once rode a friends Laverda Jota aout 20 years ago and I seem to remember it had the same crank throw, although it was a triple.
 

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There's a cool animated gif around somewhere...

Its pretty darn hard to make a single pin 90 deg twin fire at even intervals:)

Think of it this way, each cylinder fires every 720 deg, there's two cylindes (so one fire every 360 deg) and they are 90 deg off from eachother....
 

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As stated...take a look at the cam timing diagram in the manual or other visual aid...the front fires, the rear 270 degrees after and the next front fire is 450 degrees of crank rotation after that.
 

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As stated...take a look at the cam timing diagram in the manual or other visual aid...the front fires, the rear 270 degrees after and the next front fire is 450 degrees of crank rotation after that.
:thumbup 270 & 450 then nothing for a long time :laugh

(It depends on the angle and whether the conrods share a common pin. Ours is the same as a Ducati, Honda etc. The TRX is a parallel twin with offset crank pins so it gets a 90 degree firing effect too.)
 

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I was looking at a TRX before I decided on the TL. Yes, offset timing to make it feel like a V-twin. They sound pretty good too but the suspension & headlight are from the dark ages! 5 speed tranny too :(
 

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Discussion Starter #8
Thanks for the info and the neat graphics, guys. Actually, upon thinking about it, I think the Laverda fired the two outside cylinders at 180 degrees and the middle one at 360, but I can't really remember. Anyway, it was a triple, not a twin.
 

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Wow, at last something i can reply about on a Laverda, have 5. Moto Guzzi V twin's are also a 270 degree firing interval. Wasted spark ignition systems mask the firing interval sometimes, in the end it is the cam timing that governs true firing interval.

Laverda 180 crank triples, most published articles get it wrong. Starting from the left to right cylinder, 0 degree-fire, 180 centre fire, 360 right fire, 540 no fire, then 720 or 0 degree fire the left again, or Bang-Bang-Bang-nothing-bang etc etc. Can sound like a 4 cylinder with a droped cylinder at idle, just loverly to listen at idle, sometimes i just start it up to hear the idle over a cup of tea...pathetic i know. Love the sound of 270 twins almost as much.

There is a triple cylinder "120" motor in the laverda lineup, though it is really a 240 degree firing interval on the cam.

Dogsoup, hoped you like the ride on a Jota.
 

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Discussion Starter #10
Thanks for the info. about the firing cycle, Jota 81. And yes, I enjoyed the ride on the Jota very much, although it was kind of scary above 7,000 rpm. I was a bit of a novice at the time. I seem to recall the clutch was really heavy, but that was probably par for the course with big bikes in those days.
 
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