csj
Member
Posts: 992
I used to be a wolfboy, but I'm alright NOOOOOWWWW
Peterborough Ontario Canada
|
 |
« on: October 12, 2009, 08:19:27 PM » |
|
About 5 years ago I test-rode a KZ1100, brand-spankin new
tiny crotch rocket. It was about 550 lbs, and a huge 140 hp.
Fastest hardware I've been on so far.
I am 6 ft and was 260 lb at the time, it was so small, and my back end was up so high I must'o looked like a cat in heat.
Anyway, it was just 1100cc, so where did they get the 140 horse?
I figured it was the DOHC, more air in-out.
Would it be a big deal to build a flat six DOHC?
Subaru has a dohc boxer! Why not Honda.
Maybe the dohc heads would make the engine cases look fugly.
With dohc, maybe the supercharger would not be needed.
That thing made the valkyrie seem like a turtle, made the 'hares'
stand up on my neck. Thoughts on flat DOHC?
|
|
|
|
|
Logged
|
A guy called me a Ba$tard, I said in my case it's an accident
of birth, in your case you're a self made man.
|
|
|
|
PatrickDoss
|
|
« Reply #1 on: October 12, 2009, 08:34:13 PM » |
|
DOHC makes the cylinder head wider. Turn that head sideways on a boxer engine, that makes it taller. That reduces ground clearance for cornering.
Most of the extra horsepower on the sportbikes comes from RPM. Remember, Horsepower is torque over time. A lot of it also comes from the valve timing being changed to accomodate the small displacement, higher revving design.
A 6.0 liter in a Chevy truck doesn't make the same horsepower as a 6.0 liter in a Chevy Corvette. There's a lot more involved than valves.
|
|
|
|
|
Logged
|
|
|
|
|
F-106
|
|
« Reply #2 on: October 13, 2009, 01:10:51 PM » |
|
honda took a motor already in prduction and hotroded it for the valk. in doing so they were able to get the best overall performance for a bike they intened on building. i heard figures of 7 million bucks to develop the valk and that is not bad consedering it was a new bike with a reworked motor. the motor alone was $5,500 of the $14,000 price tag. i believe if they it would have been too costly to due the DOHC version and the wing motor was never designed to have one in the first place. also i think the MPG would have suffered and with only a 5.3 gallon tank that may have been a problem as well. i think you are on the right track with your thinking. more HP would be nice. now, how about a DOHC flat 6 with fuel injection and a 7.5 fuel tank? that would be interesting  About 5 years ago I test-rode a KZ1100, brand-spankin new
tiny crotch rocket. It was about 550 lbs, and a huge 140 hp.
Fastest hardware I've been on so far.
I am 6 ft and was 260 lb at the time, it was so small, and my back end was up so high I must'o looked like a cat in heat.
Anyway, it was just 1100cc, so where did they get the 140 horse?
I figured it was the DOHC, more air in-out.
Would it be a big deal to build a flat six DOHC?
Subaru has a dohc boxer! Why not Honda.
Maybe the dohc heads would make the engine cases look fugly.
With dohc, maybe the supercharger would not be needed.
That thing made the valkyrie seem like a turtle, made the 'hares'
stand up on my neck. Thoughts on flat DOHC?
|
|
|
|
|
Logged
|
|
|
|
Daniel Meyer
Member
Posts: 5493
Author. Adventurer. Electrician.
The State of confusion.
|
|
« Reply #3 on: October 13, 2009, 03:03:45 PM » |
|
Anyway, it was just 1100cc, so where did they get the 140 horse?
They traded longevity and reliability for horsepower. |
|
|
|
|
Logged
|
CUAgain, Daniel Meyer  |
|
|
|
Madmike
|
|
« Reply #4 on: October 13, 2009, 07:10:24 PM » |
|
Anyway, it was just 1100cc, so where did they get the 140 horse?
I figured it was the DOHC, more air in-out.
How many RPM did it turn?? Horsepower is most always attainable at a cost - usually fuel consumption and longevity. We used to take engines that were rated at 185HP in an automotive application, add a turbo to the already blown engine, intercooler and aftercooler, fuel cooler, military spec high output injectors and boost the RPM so that they would put out 415 HP. They were used as marine engines and proved reliable for 10,000 hour cycles principally because in the marine application they weren't subjected to the load variations and heat stresses that automotive applications demand - pretty much constant load rather than up one side of the hill and down the other. |
|
|
|
|
Logged
|
|
|
|
csj
Member
Posts: 992
I used to be a wolfboy, but I'm alright NOOOOOWWWW
Peterborough Ontario Canada
|
|
« Reply #5 on: October 14, 2009, 01:05:05 AM » |
|
How many RPM did it turn?? I made mention of the size of myself and the size of the bike so that one could see in their head a tiny little bike with a big dude on it. ( Great Dane humpin a Chihuahua or what ) My full face helmet was fully out, over, and beyond the front wheel. Half my weight was on top of the front wheel, and at only 2K or 2.5K rpm that thing was lifting the front wheel. Astounding. Of course at higher rpm that KZ was almost scary, so much juice. I'm sure it was just a stock straight four cyl. with some slick ignition timing, no turbo, no blower, no extra cooling. My old V65 Magna had DOHC at 1100cc and it had the same HP as the Valk, less torque though. All the DOHC bikes I've seen have these huge knuckles for the cams to reside, lay that profile down flat and you've got an unattractive package. Well, give me 30 or so extra ponies and I'll live with the ugly. |
|
|
|
|
Logged
|
A guy called me a Ba$tard, I said in my case it's an accident
of birth, in your case you're a self made man.
|
|
|
|
CajunRider
|
|
« Reply #6 on: October 15, 2009, 10:00:42 AM » |
|
Notice that those rice burner (crotch rocket) engines turn up to something like 14,000 RPM.
Now think, a 650cc engine turning at 14,000 RPM... that's 9.1 litters of fuel/air pushed through the engine per minute.
Now think, a 1300cc engine turning at 7,000 RPM... that's 9.1 litters of fuel/air pushed through the engine per minute.
So... that 650 COULD push the same amount of power the 1300 could... but at what cost??? The 650 would last only HALF as long as the 1300.
Of course, timing/cams/charging/compression/etc/etc/etc all make a difference also, but this is bringing it ALL down to RPM... if ALL else is the same.
So, would you rather a 650cc engine that needs a re-build at 50K miles, or a 1300cc engine that needs a rebuild at 100K miles??
Or, for that matter, a 1520cc flat six that's known to go 200K + miles before needing a re-build???
Bottom line, you can't get something for nothing. More power means less reliability. At the time of building the Valk, Honda chose reliability over power.
|
|
|
|
|
Logged
|
Sent from my Apple IIe
|
|
|
|
SPOFF
|
|
« Reply #7 on: October 15, 2009, 07:33:19 PM » |
|
About 5 years ago I test-rode a KZ1100, brand-spankin new
tiny crotch rocket. It was about 550 lbs, and a huge 140 hp.
Fastest hardware I've been on so far. Sounds heavy and slow. Current 600cc crotch rockets weigh about 375 and are pushing 120 hp. (And these are the bikes they sell as "entry level." )  Of course these bikes have redlines at 16,000 rpm and practically no power under 12,000. Riding a Valk with a similar powerband would suck mightily. I got seriously flamed here a few years ago when I suggested that a motor that spend its entire life at 15,000 rpm would wear out in 40,000 miles. Apparently (I'm told) they'll do this for hundreds of thousands (or even millions) of miles just like a Gold Wing! I'm not sure how you'd test this since a large number of 600cc sportbikes are totalled within 1,000 miles and often kill their owner in the bargain. On the plus side, a DOHC Valkyrie wouldn't need a side stand. Being 5 feet wide, you could lean it over onto the cylinder head to park. |
|
|
|
|
Logged
|
|
|
|
|
CajunRider
|
|
« Reply #8 on: October 16, 2009, 07:25:19 PM » |
|
I got seriously flamed here a few years ago when I suggested that a motor that spend its entire life at 15,000 rpm would wear out in 40,000 miles. Apparently (I'm told) they'll do this for hundreds of thousands (or even millions) of miles just like a Gold Wing! I'm not sure how you'd test this since a large number of 600cc sportbikes are totalled within 1,000 miles and often kill their owner in the bargain.
You were pretty darn close!! I've seen a couple of those 15K rpm engines at 50K miles... burning oil like it was gas. |
|
|
|
|
Logged
|
Sent from my Apple IIe
|
|
|
|
Madmike
|
|
« Reply #9 on: October 16, 2009, 07:55:17 PM » |
|
A fellow that I worked with 30 years ago used to equate engine life to fuel consumption/RPM/Horsepower.
Later Caterpillar used this same basic theory with their engines that were set up for marine use - (ie 3208's that were in lifttrucks were setup for about 120 HP wheeras the marine models with same basic block crank and heads but turboed, with combustion air cooling and a differently calibrated fuel system were rated for 460 HP) - in their maintenance manuals they gave a basic engine life expectation chart based on the fuel usage over a lifetime.
|
|
|
|
|
Logged
|
|
|
|
|
Puffs Daddy
|
|
« Reply #10 on: October 17, 2009, 05:53:57 AM » |
|
About 5 years ago I test-rode a KZ1100, brand-spankin new
tiny crotch rocket. It was about 550 lbs, and a huge 140 hp.
Fastest hardware I've been on so far.
I am 6 ft and was 260 lb at the time, it was so small, and my back end was up so high I must'o looked like a cat in heat.
Anyway, it was just 1100cc, so where did they get the 140 horse?
I figured it was the DOHC, more air in-out.
Would it be a big deal to build a flat six DOHC?
Subaru has a dohc boxer! Why not Honda.
Maybe the dohc heads would make the engine cases look fugly.
With dohc, maybe the supercharger would not be needed.
That thing made the valkyrie seem like a turtle, made the 'hares'
stand up on my neck. Thoughts on flat DOHC?
Not a boxer, but Honda has built a six cylinder DOHC bike. As others have noted, reconfiguring it into a boxer design would make it even wider than it was already. Not as tall though. http://www.bikez.com/motorcycles/honda_cbx_1981.php |
|
|
|
|
Logged
|
|
|
|
|
roboto65
|
|
« Reply #11 on: October 17, 2009, 06:35:51 AM » |
|
Later Caterpillar used this same basic theory with their engines that were set up for marine use - (ie 3208's that were in lifttrucks were setup for about 120 HP wheeras the marine models with same basic block crank and heads but turboed, with combustion air cooling and a differently calibrated fuel system were rated for 460 HP) - in their maintenance manuals they gave a basic engine life expectation chart based on the fuel usage over a lifetime. I guess that is for diesel and I figure the life is long LOL I have detroit V16s to 8cyls end to end I burn about 1200 gals a day Oh and then there are my Gens |
|
|
|
|
Logged
|
Allen Rugg VRCC #30806 1999 Illusion Blue Valkyrie Interstate 1978 Kawasaki KZ 650 project  |
|
|
|
fstsix
Guest
|
|
« Reply #12 on: October 17, 2009, 07:29:07 AM » |
|
|
|
|
|
« Last Edit: October 17, 2009, 03:01:10 PM by fstsix »
|
Logged
|
|
|
|
|
fstsix
Guest
|
|
« Reply #13 on: October 17, 2009, 07:56:57 AM » |
|
|
|
|
|
« Last Edit: October 17, 2009, 03:07:04 PM by fstsix »
|
Logged
|
|
|
|
|
