[barett]

From Kevin Cameron at CycleWorld

The R3’s engine is a parallel twin of 68.0 x 44.1mm bore and stroke, the bore exceeding the stroke by the same high 1.55 oversquare ratio as in the 2015 R1. Yamaha learned the value of having a signature sound from the crossplane-crank R1’s “V-8 voice,” and in giving R3 a 180-degree crank will achieve a syncopated, interesting sound. This is a liquid-cooled sport engine, with DOHC, four valves per cylinder, fuel injection, and forged pistons.

Peak power comes at 10,750 rpm and will likely be in the vicinity of 45 hp. Its “offset cylinders” lessen friction by reduc*ing the angularity of the connecting rods on the power stroke, thereby pressing the pistons less hard against their cylinder walls. The liner-less bore is not hard-plated as in the Nikasil process but instead relies on the hardness of myriad silicon particles already present throughout the part, honed smooth and then treated. This saves 3 to 4 pounds in liner weight and adapts well to production.

 

[YamahaPWR]

And it's for this reason that I love Yamaha and even more of a reason to see why a brand like Lexus would contract out the development of the LFA's engine sound to Yamaha.

 

[AJ Nin]

One thing to note is while the r3 looks like a super bike at first glance, it is set up more like the Ninja 300 which is more of an all-around or street/highway/commuter bike. Of course you can race it, but the riding position is not that of a super sport bike like the GSX-r600 for example. The handlebars of the r3 are well above the triple clamp and the seat is low so you reach forward and up a little, not down to get to the handlebars. The reach is also not very far due to the short wheel base and other design parameters.


Yamaha is going after the Ninja 300 market after all, not the super bike market which is more race oriented. Oh, I know they show the r3 on the race track going all out in a tucked position a lot in their ads, and no doubt it will race very well, but it is mainly a street bike. Probably more than 90% of r3 owners will never go to the track. I won't and didn't with my race bike either.

 

[AJ Nin]

When comparing the r3 to the Ninja 300, the r3 is 11 lbs lighter than the non-abs Ninja 300...but this is at a trade-off. The gas tank of the r3 is 3 L smaller....that's 5 lbs right there and that extra 3 liters of fuel might come in handy at some point. The other way to look at that is that you can lose 5 lbs. from the Ninja 300 by putting 3 liters less fuel in it. The r3 has no slipper clutch but the Ninja has a standard slipper clutch. I suspect that weighs 3 lbs. or so. Let's just say it probably doesn't qualify as a selling point to say the r3 is lighter than the Ninja 300. The details of that lighter weight do not favor the r3.

 

[YamahaPWR]

The way I see it, for most folks buying one of these, the difference in weight won't matter to them in the way they'll be riding it and where they'll be riding

 

[Ho11ywood195]

When comparing the r3 to the Ninja 300, the r3 is 11 lbs lighter than the non-abs Ninja 300...but this is at a trade-off. The gas tank of the r3 is 3 L smaller....that's 5 lbs right there and that extra 3 liters of fuel might come in handy at some point. The other way to look at that is that you can lose 5 lbs. from the Ninja 300 by putting 3 liters less fuel in it. The r3 has no slipper clutch but the Ninja has a standard slipper clutch. I suspect that weighs 3 lbs. or so. Let's just say it probably doesn't qualify as a selling point to say the r3 is lighter than the Ninja 300. The details of that lighter weight do not favor the r3.

I have to disagree a 11 pound loss of weight on a 300 cc bike makes a big differance. In terms of handling accleration and braking the advantage is on the R3 side. I took 7 pounds off my CBR 1000RR and felt the difference the first turn i took at the track even from left to right I was able to turn in faster with less effort. Just pick up a 10lb dumb bell when you ride your bike then place it in your back pack and ride around with it then see what a difference it makes during riding. Then lose it im willing to bet you will eat your words.

 

[EcoRider]

Why didn't they keep the 360 degrees ptwin system?
It could save them some counter weight, resulting in lower engine weight, faster engine revving, and smoother sound.

I'm one, I don't really care about the sound. The less noise, the better for me.
I was wondering if it had a vtwin engine, because it didn't sound like a 360 deg ptwin.

Does 180deg ptwin design somewhat help reduce vibrations?
Does it in any way improve performance?

I don't think so....

Also, isn't it harder for the engine to have 2 cylinders unequally yoked? The first piston will have to carry most of the weight after 540 degrees of no combustion, and the second one has to do very little to work, as it fires right after the first.

 

[EcoRider]

One thing to note is while the r3 looks like a super bike at first glance, it is set up more like the Ninja 300 which is more of an all-around or street/highway/commuter bike. Of course you can race it, but the riding position is not that of a super sport bike like the GSX-r600 for example. The handlebars of the r3 are well above the triple clamp and the seat is low so you reach forward and up a little, not down to get to the handlebars. The reach is also not very far due to the short wheel base and other design parameters.


Yamaha is going after the Ninja 300 market after all, not the super bike market which is more race oriented. Oh, I know they show the r3 on the race track going all out in a tucked position a lot in their ads, and no doubt it will race very well, but it is mainly a street bike. Probably more than 90% of r3 owners will never go to the track. I won't and didn't with my race bike either.

You don't need to be leaning forwards too much on these bikes. They only go 100mph tops.
You will want lower handles the moment you go over 100mph barrier, like 120, or 150mph.
lower handlebars are very uncomfy at regular street speeds.
from the looks of it, the handlebars should be placed 3in higher, and 2 in backwards, for a more comfortable grip at speeds between 45mph and 85mph, which is where you'll be riding the bikes most of the time.

 

[EcoRider]

The way I see it, for most folks buying one of these, the difference in weight won't matter to them in the way they'll be riding it and where they'll be riding

Indeed. Anything under 400lbs is beginner safe Imho.
The Yamaha and Ninja get pretty close to that weight limit.
My Rebel is 325LBS, and feels almost like a steel bicycle, very nimble.

 

[les1]

Why does the clutch rattle and bang on tickover, yet the noise disappears when the lever is pulled in?

 

[tw586]

Why didn't they keep the 360 degrees ptwin system?
It could save them some counter weight, resulting in lower engine weight, faster engine revving, and smoother sound.

I'm one, I don't really care about the sound. The less noise, the better for me.
I was wondering if it had a vtwin engine, because it didn't sound like a 360 deg ptwin.

Does 180deg ptwin design somewhat help reduce vibrations?
Does it in any way improve performance?

I don't think so....

Also, isn't it harder for the engine to have 2 cylinders unequally yoked? The first piston will have to carry most of the weight after 540 degrees of no combustion, and the second one has to do very little to work, as it fires right after the first.

The main reason for 180 degree crank is parasitic pumping loss, on 360 cranks both pistons rise and fall together, so the crank case volume has to increase and decrease, in a 180 the volume is constant as one piston falls the other rises so the air in the case moves from side to side. as the pistons also balance each other out it is better mechanically, the down fall is power pulse is not even 180-540 but this now bring into play the big bang engine design, it is very hard to understand ( i even struggle with this and I teach engineering ) but its more efficient and produces more torque for a given capacity, eg big vee twins have been using this for years, its to do with crank acceleration and de acceleration, it just works, I have a FZ/MT07 with a 270 crossplane crank and it is a torque monster that revs as well.