Best engine design for a motorcycle?

[XS650]

Originally Posted By: Johnny
I just want to say I like this topic. Here we all are having a civil conversation about motorcycles.

Amazing isn't it.

Anyone interested in 3 cylinder bikes should Google Kawasaki 2-stroke 3 cylinder

Quote:
Seriously, indeed. Consider: Seventy-four explosive horsepower stuffed into a powerband only 2,800rpm wide; a frame better suited to a moped; fuel consumption that would drop below 20 miles per gallon; spark plugs that fouled in less than 10 minutes of city riding; and all this accompanied by clouds of blue smoke and the raucous ring-a-ding racket of a big air-cooled multi-cylinder two-stroke.


That is a reasonably accurate description.
http://www.motorcycleclassics.com/motorcycle-reviews/2006-07-01/kawasaki-h2-mach-iv-social-misfit.

They were fun to ride if you were young and foolish and didn't kill your self.

 

[Silk]

I prefer a single or twin,multis don't interest me at all....but a triple is in a class of it's own.A 90 deg V twin is great,but the packaging not so.I had an XLV750,this was a 45 deg V twin,with 90 deg firing impulses.Suzuki did something similar with the VX800 - they made two engines,one that was balanced,and one that wasn't - different firing intervals.

I like two strokes,and the late model ones with power valves and water cooling make power everywhere and are very reliable.The DT230 was one of the most high tech road legal 2 strokes - electronic power valve,electric start,traction control.They stay together far longer than any 4 stroke making no where near the same hp for the same capacity.

I like my airhead - so simple and easy to work on,run forever I hope.

 

[Steve S]

I owned a 1971 Kawasaki H1 . A 500cc 2 stroke 3 cyl the 750 really wasn't faster I used to ride with a couple of buddies that owned them. I never fouled a sparkplug in it during the 4 years I owned it and did lots of freeway rides at 80 mph and got 50 mpgs .The motor cycle was lots of fun and a pleasure to ride .Though todays motorcycles outperform it in every way cept for personality. I could run it at 100+ mph untill it ran out of gas.

 

[Shannow]

Laverda Jota was a nice 3 cyl...with a funny firing order, which every one seems to like to play with these days.

Look at the NSU Ro80, versus the NSU Prinz, and that's why I think wankel is a bike engine, not a cruiser.

Low CG for starters, and there have been heaps of air cooled Wankels over the year, just not those that you see in car and bike mags.

 

[Redline955]

I've had 3 triples. a 400 Kawi 2 stroke, '74 Triumph Trident, and an '01 Triumph Speed Triple. More torque than an I4, and nice pull in the top end. And you can't beat the sound!

 

[Johnny]

In 1973 I owned a Suzuki GT750 which was a 3-cylinder, liquid cooled, 2-stroke. They were really a fun bike to own back then and the sound was unmistakable. Mine looked like this one.

http://motobr.files.wordpress.com/2009/09/suzuki-gt750-19711.jpg

 

[kballowe]

OK, so someone educate me here. I always thought that the parallel twins would cool better than the v-twins, as the jugs were side-by-side.

 

[Johnny]

In most cases that is correct. Water cooling on the Japanese bike took care of their problem. Harley does it with a redirection of air. That is one of the reasons I love the opposed cylinder air cooled BMW's.

 

[boraticus]

"Best" covers a lot of different aspects.

Best reliability.
Best fuel consumption.
Best acceleration.
Best power to weight ratio
Best to service.
Best balance (least vibration)
Best physical size
Best for cruising, touring, racing
Best for multi-surface riding
Best center of gravity
Best looking and best sound for those who think it matters.

There are probably more aspect that I've over looked. However, my preference would be a liquid cooled 750cc two stroke parallel twin with efi.

Why? Compact, very powerful, very simple, comparatively light, very reliable, and smooth. With a nice set of expansion chambers and properly balanced silencers, a two stroke's exhaust note is relatively quiet but can be pretty wild when wound out. did I say, very powerful?

Modern two stroke engines used in snow machines and outboard marine engines are fantastic pieces of technology. Bombardier's E-tec series two strokes are as clean and fuel efficient as many four strokes while being much lighter and more powerful, pound for pound. This is a technology that should never have been put on the back burner.

 

[RonH]

I still have a triple, a 1974 Kawasaki H2 750 that I've owned for 31 years now. By far the best engine ever--well I don't think. I've had lots of engines, caught on that first Honda V4 garbage and never desired another V4 to this day. Besides the oiling problems, had the carbs between the cylinders and on hot days would boil the gas and run like [censored]. Maybe fuel injection solved this? I don't want one, but the VF1200 looks interesting as well as the new vmax. I'll still take my GL1800 goldwing as the best engine. BMW would be a great choice too, but dealer visits to the tune of $1000 a yr doesn't appeal to me.
Ha, cr*p is a censored word, sorry. Better to say it "did not run too good hot". Will that pass

 

[bigbird_1]

Originally Posted By: boraticus
Bombardier's E-tec series two strokes are as clean and fuel efficient as many four strokes while being much lighter and more powerful, pound for pound. This is a technology that should never have been put on the back burner.


The E-Tec's are great technology. They seem to be more reliable in snowmobiles than outboards. A friend owns a SkiDoo dealership and his warranty and service repairs for the E-Tec's are quite low. The outboards seem to be more repair prone. He credits that to the reduced space and size allowed for the same parts inside an outboard motor cowling than under a snowmobile hood. Ever see the crazy plumbing required for an Evinrude outboard? An E-Tec motorcycle engine would be very interesting. The challenge for a motorcycle would be the cooling. The E-Tec's use stratified charge burning, which burns at a very lean ratio, sometimes as high as 18:1 air to fuel. That means a lot of heat is produced. Not a problem with outboards or snowmobiles. Potentially a much bigger problem with motorcycles.

 

[boraticus]

I agree that the GL1800 and the Valkyrie versions of it are beautiful engines. They are statements of technological achievement but not sure if I would agree that it's the best design for a motorcycle. I own an '03 Valkyrie and think it's a magnificent machine but the bulk and weight of the engine takes away some of it's advantages. Not that it has any negative effect on the handling of the bike at speed. With the low CG, it's a great handler. However when muscling the bike around in the garage, the weigh becomes very noticeable. The engine is very appealing to the eye.

http://en.wikipedia.org/wiki/File:Flat.six.honda.valkyrie.arp.750pix.jpg

 

[ZGRider]

Some of you all missed my point, I really shouldn't have said "best"

What I should have said was "if you could design your own motorcycle, what type of engine layout would you use?"

Some folks just want to parse words -- "there is no best"

But for the rest of you, keep the replys coming -- we are educating each other.

Right now, it's neck and neck between in-line triples and V-Twins.

 

[ZGRider]

Originally Posted By: kballowe
OK, so someone educate me here. I always thought that the parallel twins would cool better than the v-twins, as the jugs were side-by-side.

Parallel twins have much more vibration than 90 degree V-Twins. 90 degree V-twins have perfect primary balance. However, parallel twins are gaining in popularity lately -- BMW F800, Kaw Versa/Ninja 650, Triumph twins, Suzuki Bergman, etc.

 

[bonnie john]

well i own a bsa triple, a triumph and norton twin and a fatboy, so the jury's still out...

i like the 69 bonneville engine layout the best, all things considered

 

[bigbird_1]

Originally Posted By: kballowe
OK, so someone educate me here. I always thought that the parallel twins would cool better than the v-twins, as the jugs were side-by-side.

I agree with you. The rear cylinder in a V-twin, though slightly offset from the front cylinder, does suffer from increased heat due to the blocking effect of the front cylinder. That being said, HD, Yamaha, Indian and any others that use air cooling for their V- twin engines also rely on a heavy dose of oil cooling to get rid of that extra heat. I would also think that parallel twins are much easier to cool than V-twins (except for Moto-Guzzi).

 

[heavyhitter]

My favorite is a single cylinder 2-stroke, reliable, light and lots of power.

I love the torque of twins but had the engine braking in tight turns.

 

[eljefino]

Originally Posted By: XS650

Anyone interested in 3 cylinder bikes should Google Kawasaki 2-stroke 3 cylinder

Quote:
Seriously, indeed. Consider: Seventy-four explosive horsepower stuffed into a powerband only 2,800rpm wide; a frame better suited to a moped; fuel consumption that would drop below 20 miles per gallon; spark plugs that fouled in less than 10 minutes of city riding; and all this accompanied by clouds of blue smoke and the raucous ring-a-ding racket of a big air-cooled multi-cylinder two-stroke.


That is a reasonably accurate description.
http://www.motorcycleclassics.com/motorcycle-reviews/2006-07-01/kawasaki-h2-mach-iv-social-misfit.



You'd still get chicks.

 

[BigCahuna]

Nothing says best in style or performance then the Boss Hoss, 502 cu in Chevy v-8 in a motorcycle frame. Water cooled, smooth, powerful, and will rip your arms out of their sockets if you turn the throttle all the way. Not to mention the warm feeling you get on those 90 degree days riding around town.I'm surprised no one mentioned it yet,and at about $40,000 everyone can afford one.,,

 

[eljefino]

Originally Posted By: bigbird_1


I agree with you. The rear cylinder in a V-twin, though slightly offset from the front cylinder, does suffer from increased heat due to the blocking effect of the front cylinder. That being said, HD, Yamaha, Indian and any others that use air cooling for their V- twin engines also rely on a heavy dose of oil cooling to get rid of that extra heat. I would also think that parallel twins are much easier to cool than V-twins (except for Moto-Guzzi).


All that and jetted richer in the rear too on my bike at least.

Some modern stuff like knock sensors, feedback fuel systems (that do ok on E10 fuel), EFI (no little stupid jets to clog), and an ignition timing curve that takes load or lack thereof into account... are all missing on my bike and would be awesome.