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Old 05-16-2011, 04:41 AM   #11
Larry
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Originally Posted by mlynch001 View Post
Harley has it right with their V-twin, 2 valves and push rods. The SOHC 4 valve Victory serves to make the engine taller than it needs to be and adds unnecessary complexity! Looking at the RPM and power numbers, there is NO other conclusion to be made. WHERE is the payoff or the necessity for the SOHC 4 Valve design? Any Engine designer needs to ask this question when they start, not just add a feature because it speaks of "performance"
Sorry... wrong.

1. The Victory engines make more power per cubic inch than Harley engines in emissions legal trim. They also have less issues with being lean, run a lot cooler, and have no need to shut off the rear cylinder at idle to keep from melting down. This stock 100" Vic made 76 HP, while a stock HD "power pak" 103 makes 65-67 HP.

2. What the 4-valve heads give you is two-fold. 1) Broader spread of torque across the tach, and 2) the potential to make lots more power, with better low end torque, from a much milder set-up. For example, middle-of-the-road performance cams for Harleys are .600 to .650 lift, while Victory performance cams are at most .495 lift.

3. The story would read a lot differently if they chose more wisely. Any decent airbox is worth a dozen HP and for $300 that bike could be making 95/105 at the rear wheel through that crappy Cobra pipe. The same mods to a Harley will get you to around 76 HP.

4. Look at some comparison tests of the new breed of baggers. The Victory bikes have the tallest engine, the most rear suspension travel, AND STILL HAVE THE LOWEST SEAT HEIGHT. A Vision has a lower seat than a Sportster! What was the disadvantage of the taller OHC engine again?

5. Harley's basic engine foundation is weak. If you want to make any decent power you will need to weld/plug/true the crank and add tapered bearings to the ends if you expect the motor to live.
Harley crankshaft issues - Google Search
What did Harley do about this? They changed the specs on crank run-out from a max of .003" to a max of .012" (4 times greater). They came up with a download that removed low end grunt too. They suggested that owners don't use engine breaking or lug the engines... yes, it's true.
You can make 170 HP reliably with stock Victory cases, bearings, and crankshaft.

"Harley has it right"? Really? This is a comparison you don't want to make...


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Old 05-16-2011, 05:20 AM   #12
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Originally Posted by Larry View Post
"Harley has it right"? Really? This is a comparison you don't want to make...

Or Larry will beat you to death with a bat made of rolled up dyno charts.

68 versus 76 hp. Where's Anaranjalalala when we need him?
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Old 05-16-2011, 06:29 AM   #13
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Or Larry will beat you to death with a bat made of rolled up dyno charts.
A bat made of rolled up dyno charts is a fine blunt instrument - LOL

Vic definitely is a solid contender in this engine configuration. The Yamaha engine is cool too, but it seems these Vics hop up really well and are rock solid if one does the right things. I don't know about the Yamahas.
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Old 05-16-2011, 07:19 AM   #14
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The Yamaha engine is cool too, but it seems these Vics hop up really well and are rock solid if one does the right things. I don't know about the Yamahas.
The Yamaha 113" engine is a sweet mill and with just external mods to improve breathing will make 100 HP and 120 ft-lbs to the tire (most cruiser owners would be more than happy there). What holds them back is the pushrod valve train, seriously undersquare design (100mm bore/118mm stroke), and low rpm rev limit.

The Raider/Roadliner/Stratoliner is hard to beat... Look good, sound good, run good, and sell at a nice price point. I put 600 miles on a Stratoliner and it made the short list when I was shopping for a new bike. The floorboards and beach bars would have to go...
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Old 05-17-2011, 10:36 AM   #15
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To get back on topic ...

So, y'all spent roughly $10k (on parts) and you ended up with a slower, clunky metric wannabe with a typical black & chrome "theme"?? You needed to change the title to "8 is Enough" & left the damn thing stock for all the good your part selections did. There's nothing even remotely "Evil" about it or groundbreaking or innovative. You did manage to take nice factory "boulevard cruiser" and create a Honda. Great job fellas!
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Old 05-17-2011, 11:40 AM   #16
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I think it was a good article and project. I'm certain that the bike rode/handled/stopped lots better than the stock 8-Ball. Although the performance enhancements didn't actually net any performance gains, that wasn't the fault of Motorcycle.com. Polaris/Victory owns that debacle.

If someone who was thinking of buying one of these bikes or already owns one got some insight into improving the suspension/brakes and learned not to buy their exhaust from the Victory accessory catalog, then the article was not a wasted effort.
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Old 05-17-2011, 12:11 PM   #17
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Quote:
Originally Posted by mlynch001 View Post
Harley has it right with their V-twin, 2 valves and push rods. The SOHC 4 valve Victory serves to make the engine taller than it needs to be and adds unnecessary complexity!
Larry did pretty well seal this argument with his tricky facts & bewildering figures ...

But let me throw another kernel at you (the unconvinced). There's a funny little term called "mechanical advantage" (MA). MA is the factor by which a mechanism multiplies the force or torque applied to it. It relates directly to creating an "ideal machine". Ideal machine - Wikipedia, the free encyclopedia This is why some dumb engineer spent their life developing the SOHC 4 valve engine. By eliminating the lifters & pushrods you so love, they increased the mechanical advantage of the entire assembly. Weird right?

Why does that matter when pushrods look cool? Well, glad you asked ... This may be the most highly debated question in all automotive internet forums. It's not that the definitions are in doubt. They're obviously objective. The controversy centers around which is more important.

Force
Force is the pressure of one mass against another, and is one of the primary units in all of physics. Gravity is an easy example of a natural force and is written in the English system as "pounds". So we also use pounds as the basic unit of force.

Work
Work is defined as force over distance and is calculated as Work= Force * Distance. In other words, work is achieved when force causes an object to move. The force placed on the object and the distance it moves are calculated as the work done.

Power
Power was originally defined by the engineer James Watt as the amount of work that can be done in a certain amount of time. So its function is Power = Work / Time.

Torque
Torque is defined as the force at any one point on the edge of a circle in the exact direction of the rotation multiplied by the radius (distance from the center). This comes from the calculus/geometry concept of a "tangent", a line which touches exactly one point of the edge of a circle.

Horsepower
Horsepower is a unit of power. It can be defined in many ways. In its basic sense, it's defined as work done in a straight line as described above under "Power". But when the work is not done in a straight line, it must be defined in a different way: torque.

Horsepower = (Torque X RPM)/5252

Now although horsepower in this instance is defined by rotational forces, it is no different than straight-line horsepower. For instance, if you wrapped a rope around the circle and allowed the torque to pull the rope, the force on the rope would now be exactly as defined above.

The point of all this is with lifters and pushrods rattling around in the engine (commonly called lash) the HD motor is doing more work to create the same unit of torque as the SOHC does by having the cam actuate the rockers.

To sum up, pushrod motors are going the way of the dodo bird because they can't make efficient use of their power. Even better solutions like the OHC engine will be phased out in the near future because electric motors require significantly less work to create the same power/torque.
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Old 05-17-2011, 12:26 PM   #18
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Quote:
Originally Posted by Larry View Post
I think it was a good article and project. I'm certain that the bike rode/handled/stopped lots better than the stock 8-Ball. Although the performance enhancements didn't actually net any performance gains, that wasn't the fault of Motorcycle.com. Polaris/Victory owns that debacle.

If someone who was thinking of buying one of these bikes or already owns one got some insight into improving the suspension/brakes and learned not to buy their exhaust from the Victory accessory catalog, then the article was not a wasted effort.
I may have been overly harsh, but with the ongoing tease of some real mods over the past few months. I was expecting more than a series of simple bolt-ons. Granted the fork swap was neat, but did they take it far enough? There's a pro-street kit out there that'll give you a 45* rake without cutting the neck. Dare I bring up the air ride rear suspension option again? How about a CAI kit or hiding the oil cooler? Adding a batwing?

Yeah, I know some of what I mentioned was purely asthetic, but in the end so was most of what they did.
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Old 05-17-2011, 05:34 PM   #19
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Evil, Stupid Torque + Evil, Dangerous Handling = Exceptionally Evil Motorcycle.
You can do a better equation then that, no variables, squared root, secret tunnels? I expected more.
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Old 05-18-2011, 06:15 AM   #20
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For Gawd's sake - don't tell GM and Chrysler that!

I know the LSx and Hemi are a bit "down on power" 'cuz of them pushrods an' all, but still....
They already know ... That's why we (the tax payers) had to bail them out of bankruptcy.

The US automakers haven't done anything progressive since the 60's. Sure they've made the blocks out of aluminum & improved FI systems, but that's like putting lipstick on a pig. They need to go back and rethink the entire powertrain design.
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