Yamaha "invent" "new" triple

FNQ1000 said:
Other triples
Honda MVX250
Aprillia cube GP
Petronas 900
BSA A75 rocket 3

Yep Honda had the NS500 GP bike and there was also the Kawasaki KR750 and Suzuki TR750

Cheers
Jason
Click to expand...
Aprilia cube? Is that right ...they called a 3 cyl motor a cube? Do you know why?
 
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.
Click to expand...

I have a Trackmaster Triumph with a 180 degree crank which was designed for that purpose.  A 360 degree twin making serious horsepower (e.g. Shell Thuet Yamaha 750) will spin the rear tire the length of the straight on a mile track because the constant flow of power prevents the tire from hooking up.  The 180 degree crank gives the rear wheel 540 degrees of 'rest' to gain traction. 
My engine was built by an East Coast racer named Greg Edmonds in the late 70s.  The story I got was that it was very successful but was retired after only one season due to changes in the rules.  There were four of these Triumphs built: 2 were destroyed in racing/testing, I have one, and  (I presume) Mr. Edmonds has the other.
It revs 'right now', like an old Honda 350, but the exhaust note has a kind of 'flat' tone that is not very pleasing.  It is very fast, however.  These days you can get cranks phased any way you like but in the 70s it was not easy to do.  This one is all steel, one piece, with welded throws.

Cheers,
Patrick Cherry
Ojai, CA  USA
 
I'll be checking out the engine tomorrow, lots of rain and storms forecast, the ideal day for a trade fair visit. :D

Hoping it does turn out to be 90/270?, would make it quite interesting and will certainly ruffle the other big players to further development of triples.

piet

 
I have been thinking about this (dangerous, I know  :-* )......

Like Robjota, I think the triple 180 engine is some way to being a big bang configuration, given the gap in the firing of the cylinders.

In the past, I heard the Laverda 180 triple described as a 4 cylinder engine with one cylinder cut off. This never made sense to me, as a normal 4 cyl. engine has outer pair and inner pair of pistons at 180 degrees to each other......so the cylinder that the Laverda triple is missing is number 2 or number 3.

So, the 180 triple is a flat plane, albeit a modified one that seems for be a version of the big bang engine.

Given that a flat plane crank has pistons at 180 degrees to each other and a cross plane has cylinders at 90 degrees to each other, I wonder how a cross plane triple would be configured? 1st cylinder at -90 degrees, centre at +180 degrees (or zero degrees) and 3rd cylinder at +90 degrees? 

Maybe that's what Yamaha are doing  (dunno)

Tried to work out how it would fire - but seemed very strange (fire centre, rotate 90 degrees fire left, rotate 180 degrees fire right, rotate 450 degrees fire left again etc etc.)

That 450 degrees is a BIG gap....

I think the Laverda 180 is: Fire left, rotate 180 degrees fire centre, rotate 180 degrees fire right, rotate 360 degrees fire left again etc. etc.

.......now my head hurts (help)

Pete
 
Dellortoman said:
Maybe it's a zero degree crank and they all fire together. Now that would be a big bang engine  :D
Click to expand...

Designed by a complete crank?  :D
 
Can't believe all of you Italian fans forgot the MV range!!!  :o

F3  675cc Triple
2011-MV-Agusta-F3.jpg


MV%20Agusta%20F3%20Serie%20Oro%20%202.jpg


Off road version
5101465529_b6490dfefd_b.jpg


And their pedigree!

500 GP Championship winning bike!
mexico025.jpg


mv_agusta_500_3_cilindri_retro_jpg_2520_1000x671_.jpg


mv_agusta_500_3_cilindri_jpg_2520_1000x671_.jpg



Philistines  :P :LOL:
Julian
 
Car manufacturers have been producing triples for a while. GM 1000cc, Daihatsu/Toyota/Citroen/Peugeot 1000cc.

A dealer told me the reason was that there were less parts and less bearings therefore less friction, therefore better fuel economy and fewer emissions, something car manufacturers major on and motorcycle manufacturers are just waking up to. My Toymotor Ego is a great engine, free revving, economical and a great sound.
 
Strewth, they will just have to build single cylinder power plants then, going on that logic.  ???
 
Just returned from the Cologne Intermot trade exhibition.  My chat with the Yamaha guy did not lead to much, he was pretty much clueless.  Could not say what the crank phasing of thetriple is, nor any other details.  He did speculate though that Yamaha might be thinking of replacing many of their fours with triples in the near future.

The engine is very compact, the displayed example obviously a (the only?) prototype as the crankcase is actually CNC milled from solid!  BTW, the silver coloured engine to the rear of the bike in the pics is actually the current Moto-GP engine.  This is almost completely CNC milled, only the cylinder block, head and water pump housing are castings!  Absolutely awesome stuff.

Apart from this, no real highlights at the show imho. Reckon the motorcycle industry no longer considers me to be a potential customer... ::)

piet
 
MickeyMoto said:
Car manufacturers have been producing triples for a while. GM 1000cc, Daihatsu/Toyota/Citroen/Peugeot 1000cc.

A dealer told me the reason was that there were less parts and less bearings therefore less friction, therefore better fuel economy and fewer emissions, something car manufacturers major on and motorcycle manufacturers are just waking up to. My Toymotor Ego is a great engine, free revving, economical and a great sound.
Click to expand...

And Suzuki, both 2 and 4 stroke, not in the same car though!
 
Not to forget 1000 and 1200cc Subaru triples used in Justy and Libero.  Bulletproof little donks!

DKW also entered 2-stroke 350cc triples in the GP, quite similar to the Honda NSR and the Lav prototype layouts.

piet
 
The pump on the back of my brigade's fire truck has three cylinders, they're everywhere, its an invasion ???
 
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