For the hard-core Engine Techs among us!

[GunMD]

It sounds very pretty.

 

[HotRodZilla]

Seems like an underachiever for an engine with 1645cc...

That's what I thought...doesn't the FJR's 1298 in-line 4 make 145BHP? What are the other 347CCs in the MOTUS engine doing? Just adding to the weight?

 

[wfooshee]

It's a torque vs. RPM thing. This motor don't spin the revs we do, so it don't make the power.

Remember, HP = Torque x RPM.

Without RPM you get less HP, even with more torque.

Compare the FJR's torque numbers to this motor, or even any "respectable-sized" v-twin.

 

[greywolf]

HP - torque xRPM /5252 to be precise , and many V-twins don't spin much past 5252 , so they don't tend to produce the HP like a inline 4.

If my HD could pull 9 grand like my FJR it would be making 190HP .. of course that will never happen , but with 111 lbs ft at the wheel it pulls fine in any gear under any load.

I hope the new design makes it into production , it would be nice to see a US built legitimate Sport Touring bike.

 

[ionbeam]

It's a torque vs. RPM thing. This motor don't spin the revs we do, so it don't make the power.
Remember, HP = Torque x RPM.

divided by 5252

Edited: I see greywolf covered it 1 minute earlier.

Since I'm here, let me add that normally aspirated 2 valve engines don't breathe as well as 4 valve engines. For street purposes 2 valve engines typically don't make the revs that a 4 valve engine will. The trade is that usually 4 valve engines don't make the low rpm torque of 2 valve engines. There are breathing work-arounds for both the 2 valve engine and 4 valve engines, but it tends to make very narrow power bands.

 

[wfooshee]

The 5252 is just a units correction constant. It's a different number if you're in metric units. I should have used "power" rather than "HP" and "rotational velocity" rather than "RPM" as I was trying to speak conceptually.

Conceptually, power = torque x rotation velocity, whatever your units end up being.

 

[RaYzerman19]

With an 11.5:1 compression ratio running on regular fuel, the anti-knock sensors are kicking in and the ECU ******* the timing........ therefore lost horsepower.

 

[user 213]

Lets say they build it. And it's even affordable, or at least comparable to the market.

Even if you go the chain oiler route,

Even if you accept the low tech pushrods w/HLAs,

Even if you like what ever they do with the exhaust,

You still have crappy lighting and a small screen and a tank too small to deal with the fuel economy this motor will likely deliver.

They are old sport bike guys that don't ride distance. They don't even have a basic idea of a long day. Their goal appears to be a sport bike that old guys can ride with a little more comfort and has a cool motor* that mimics the low end torque of a V-twin, but has more Hp.

*cool equalling what they liked in high school, but couldn't afford.

 

[charismaticmegafauna]

There are breathing work-arounds for both the 2 valve engine and 4 valve engines, but it tends to make very narrow power bands.

One notable work-around -- Honda's V-Tec: where only one intake valve was used at lower RPM -- thus, increasing intake velocity. Increased intake velocity is primarily a feature for better fuel atomization with carburetors -- not so much a benefit with F.I.

The Honda V-Tec system was notably received indifferently, at best, by riders. I doubt if anyone appreciated, much, the 2-valve mode... :blink:

Ever since Harry Ricardo offered the 4-valve head in the early 20th century ('Riccy' Triumph) -- the hand-writing's been on the wall. 2-valve head -- turn your watch back 50 years...!(not to mention push-rods...)