Yamaha "invent" "new" triple
- Thread starter breganzane
- Start date
Clumber981
Full member
Ok its wasn't a road bike but MV had their stupendous race triples.
I'm sure there must be some more road bikes if you went back to the 30/40/50s/ when all manner of engine configurations were tried.
I'm sure there must be some more road bikes if you went back to the 30/40/50s/ when all manner of engine configurations were tried.
chrisk
Hero member
- Location
- Brisbane, Australia
Hmm, I can see a 3 cylinder Zane on the drawing boards! YAMAZANE
D
Davo
Guest
And why not. I have a Yamaharley as my day ride 
OK so I was confused by the variety of motors on display in the images. It's not exactly self-explanatory.
Here is some information on crossplane crankshafts as applied to Yamaha's R1: http://www.ashonbikes.com/cross-plane_crank
If I understand it correctly, if the same principle is applied to an inline triple then the ideal crank spacing would be 120o.
And here is a link to a French site devoted to triples. I suspect someone else here has posted this previously: http://riviere67.free.fr/ACCUEIL-GB.html
bazzee
Here is some information on crossplane crankshafts as applied to Yamaha's R1: http://www.ashonbikes.com/cross-plane_crank
If I understand it correctly, if the same principle is applied to an inline triple then the ideal crank spacing would be 120o.
And here is a link to a French site devoted to triples. I suspect someone else here has posted this previously: http://riviere67.free.fr/ACCUEIL-GB.html
bazzee
chrisk
Hero member
- Location
- Brisbane, Australia
Thanks for the link Bazzee, I was their 100,000th visitor today! I won a nice prize too ...... you little ripper!
Dellortoman
Hero member
- Location
- Tasmania, Australia
That's odd. I was their 100,000th visitor too. Their counter must be on the blink.
M
Morizzi
Guest
Clumber981 said:
Guzzi experimented with a triple too. I remember seeing it at the museum. Sorry, I can't remember much more but I think it was a race bike only. The engine layed more forward than a Lav. It was like a triple breasted Falcone.
There was also this interesting variant.
http://thekneeslider.com/archives/2009/08/11/moto-guzzi-arrow-w103-3-cylinder-v-triple/
My Troop Sergeant in the Army had one of those XS750's. I only ever saw the early ones in silver. The D had a blue flash and the E had maroon/burgundy flash on the tank. From memory the F was all maroon/burgundy with gold striping or was it the the 850?
Funny how the term is 120. There is 720 degrees of rotation in one Otto cycle so the 120 should really be a 240.
G
Grant
Guest
breganzane
Hero member
- Location
- NSW Australia
bazzee said:
Nope, the "crossplane" concept is basically to produce an odd-firing order - achieved in a 4-cylinder using a 90 degree crankshaft. A 120 degree triple is an even-fire. The point of my raising this is that to create a "cross-plane" triple, the most logical crank phasing and firing sequence would be the same as the 180 Laverda triple (which was "odd-fire").
That is of course unless they do something even weirder like a 90 degree crank, effectively giving 1.5 "twisted twins" ala TRX850.
Either way I reckon it'll be an interesting engine.
Cheers
SteveB
I was looking at this yesterday and will cover myself by saying I'm out of my depth but reading Wikipedia and digesting what I read, a 180 deg triple Lav Crankshaft is a flat plane crank and the motor would be a big bang engine or have a "big bang" firing order.
Shoot me down because that's how we all learn
ROb
Shoot me down because that's how we all learn
ROb
I had a conversation with Mr Batto once and leaned that a 180 triple didn't fire at 180 degrees much to my surprise.So that tells you what I know.Suck squeeze bang blow is a bit more complicated in multi cylinder engines that I thought.I hope I got that right,it was at a rally and I was a bit pissed at the time.
Cosi
Hero member
- Location
- Kingscliff
breganzane said:
And no doubt reliable
Well I read somewhere else that the triple engine has a four-cylinder exhaust bolted onto it to demonstrate how it was narrower than an R1. Fair enough but I had to search for that explanation and frankly I find an unlabelled image like that misleading. No wonder I was (am!) confused.
My suggestion regarding the crossplane concept leading to the ideal triple crankpin spacing being 120o relates to the theory espoused in Kevin Ash's article, where the intention is to minimise the crank rotational speed variations due to transfer between the kinetic energy of the pistons and rotational energy of the crankshaft. The uneven firing order (in the R1) being a side-effect rather than a primary outcome. I still think that this is correct, although there isn't any evidence that this new engine has a 120 crank. If it's a R1 crank minus a throw, well that's very interesting, but it looks like we have to wait for more details.
cheers,
bazzee
My suggestion regarding the crossplane concept leading to the ideal triple crankpin spacing being 120o relates to the theory espoused in Kevin Ash's article, where the intention is to minimise the crank rotational speed variations due to transfer between the kinetic energy of the pistons and rotational energy of the crankshaft. The uneven firing order (in the R1) being a side-effect rather than a primary outcome. I still think that this is correct, although there isn't any evidence that this new engine has a 120 crank. If it's a R1 crank minus a throw, well that's very interesting, but it looks like we have to wait for more details.
cheers,
bazzee
G
Grant
Guest
The IDEAL crank throw for a triple is 120?, but in practice some cranks are designed with non-ideal crank throws.
Why would they do this?
It started in dirt track racing long before it became trendy with the 500 GP and then MotoGP bikes.
They used take Brit twins and rephase the cranks to replicate the H-D bikes, that were all conquering.
The theory was that a staggered crank throw allows the tyre to recover some grip before the next power pulse hits it.
I think the engines have to be more solidly designed due the the greater vibration from non-ideal crank throws.
So, the 180 triple was a big-bang engine, in some cases a very big bang (sorry Yogi, couldn't resist ).
Why would they do this?
It started in dirt track racing long before it became trendy with the 500 GP and then MotoGP bikes.
They used take Brit twins and rephase the cranks to replicate the H-D bikes, that were all conquering.
The theory was that a staggered crank throw allows the tyre to recover some grip before the next power pulse hits it.
I think the engines have to be more solidly designed due the the greater vibration from non-ideal crank throws.
So, the 180 triple was a big-bang engine, in some cases a very big bang (sorry Yogi, couldn't resist ).
sonicboom500
Hero member
Didn't Honda GP bikes have an option of Screamer or Big Bang with different crank phasing to give the
tyres half a chance at lasting a whole race.
tyres half a chance at lasting a whole race.
Yogi
Hero member
- Location
- Bellingen NSW Australia
Grant said:
No worries Grant - may it be a long time before someone else has the same bang happen...
Hi Robjota
You are correct the 180 lav is definitely a flat plane crank,it is much easier to visualise the difference between flat and cross plane in a four or eight cylinder engine.In a three cylinder engine it would be possible to phase the crank with the pins 90 degrees apart so pin 1 90 degrees to pin2 then 90 degrees to pin 3 then 180 back to pin 1.this would be like a 270 twin(trx850) with another cylinder tacked on the end.what the balance would be like without any balacer shaft would be anyones guess.
Neale
You are correct the 180 lav is definitely a flat plane crank,it is much easier to visualise the difference between flat and cross plane in a four or eight cylinder engine.In a three cylinder engine it would be possible to phase the crank with the pins 90 degrees apart so pin 1 90 degrees to pin2 then 90 degrees to pin 3 then 180 back to pin 1.this would be like a 270 twin(trx850) with another cylinder tacked on the end.what the balance would be like without any balacer shaft would be anyones guess.
Neale