A listener discussion about HP & torque

We got this email from listener Bryan Skinner, and thought the emails back and forth would make a good blog post. From Bryan: I stumbled upon your Podcast in search of finding an enjoyable conversation on motorcycling and I've really been enjoying listening to you both. Question: The issue I'm confused about is how can a Yamaha FJ-09 which is 847cc have so much more horsepower than my Honda VTX1300 cc ? My 1300cc has 57HP and 75 torque verse the FJ-09 847cc and 115HP and 65 torque. Doesn't cubic inches relate to Horsepower. Is it because the Yamaha is more modern than my 2005yr Honda VTX 1300 ? James: Bryan,
Thanks for writing. I think we’ll queue this up for an up coming show but I’ll respond here as well.
Displacement is only part of the equation. It’s really about squeezing quantities of gas and air and making it explode. I don’t know the numbers off the top of my head but I’d guess that the VTX tops out at around 6000 RPM. The FZ-09 probably doubles that number. It has less displacement but it can produce power more often. There are many other factors that can contribute such as compression ratio, power loss to friction in the motor, restrictions in the air box, other design decisions made by the engineers to produce the “feel” that they want out of the engine. RPM and compression are probably the biggest contributors.
On the upside, you’re probably getting better gas mileage AND buying cheaper gas than FZ-09 owners.
Chris: And if I may expand with some technical details to flesh that out...
Horsepower, while useful for bench racing and marketing, is a mathematically contrived measurement that's got a lot of factors going into it. In its basest form, calculating HP is simply a matter of taking the torque at an RPM, multiplying it by that RPM, then dividing that number by a fixed value of 5252. 
In the case of your VTX 1800, the I've seen docs suggesting that the torque maxes out at 120 foot pounds. To make the math easy, let's assume a good, flat torque all the way to redline. Your redline is 5750. So the resulting formula is:
T x R / 5252 = hp
120 * 5750 / 5252 = 131.4 , theoretical maximum horsepower.
In the real world, the VTX 1800 gets closer to about 105 hp with around 100 ft lbs of torque. This is because the overall breathing inefficiencies, the torque falling off at higher RPM, and mechanical drag in the engine, etc. 
According to this chart ( http://images.motorcycle-usa.com/PhotoGallerys/05PCTorque.jpg ), the VTX 1800 is good for 98 ft lbs maxed at 3700 RPM, and it starts falling off after that. So, 3700 RPM is where the engine makes its PEAK EFFICIENT POWER (which is different than maximum power) - the formula would then be:
98 * 3700 / 5252 = 69 max EFFICIENT horsepower. 
Using that chart, at max rpm of around 5500, the engine is putting out around 80 ft lbs.
80 * 5500 / 5252 = 83.8 horsepower.
No slouch by any means, especially in the "feel my arms stretch" department. 
So, as you can see, real-world numbers and theoretical, marketing numbers can vary GREATLY. 
You can modify those real world numbers a bit with better exhaust and airbox flow, tuning, etc.
But horsepower, as a thing, is fully contrived and 99.9% completely made up theoretical BS. 🙂
Me...? I'll take a nice big torque number a lower or mid-level RPM range over theoretical horsepower all day long. It's why I like twins and triples so much more than I4s. They develop their torque in lower RPM ranges, typically, and feel more spry around town.
The triple in question revs much, much higher and has a very different feel, and can produce higher contrived, theoretical (and very real) horsepower, but your VTX 1800 is going to FEEL so, so much more powerful in real-life RPM and driving speeds. Because.... it is. The Triple will have to rev much higher and feel more frenetic to develop its higher overall power.
Hope this helps. 🙂

A Burgman tale…

Today we bring you a story from listener Scott Cloninger. Chris and James, I’m finally catching up on a couple of months’ worth of back episodes of The Pace and while listening to Episode 188 Chris’ Bergman story brought to mind an excellent illustration of the Bergman’s prowess….so here goes: One of the groups I ride with occasionally is a small collection of former Clemson University students from the ’60s and ‘70s who call themselves the Clemson Café Racers.  This group has an annual weekend event called Ride-In-Camp-Out where associates gather in metropolitan Walhalla, South Carolina (I forgive you if you’ve never heard of it) and camp on one of the members’ farm.  From Walhalla the group rides most of the day Saturday and Sunday throughout western South Carolina, north Georgia, western North Carolina, and eastern Tennessee.  The members of the CCR ride an eclectic collection of motorcycles, mostly of a sporting nature.  They tend toward European marques like Ducati and KTM, but there is always lots of Japanese hardware present, as well.  These gents are all excellent riders with decades of riding experience.  They know the local roads since they’re mostly locals, and they tend to ride at a VERY spirited pace when they gather together.  The most lauded member of the group is a Gent named Tom Allred. Tom generally shows up on whatever his latest purchase is, and it’s generally the latest, greatest sporting hardware, though he has shown up on everything from a Ducati superbike to a well-worn KLR.  A few years ago Tom pulled in Friday afternoon aboard a Bergman 650.  He proceeded to tell everyone how it rides comfortably, handles well, accelerates well, and is an overall blast to ride…in fact, Tom had just ridden his Bergman from South Carolina to Alaska and back!  We all doubted his assessment despite his excellent riding chops. Saturday morning our plan was to ride from Walhalla northward to the Blue Ridge Parkway, then head east for lunch at the Pisgah Inn.  Tom lit out to show us the way.  He set a pace that was slower than that group’s typical silly speeds, but was nonetheless quite spirited and an absolute blast to ride!  This ride was punctuated by a story that’s one of those you just can’t make up…….. I’m sure you’re aware that the speed limit on the Parkway is 45 mph along most of its length.  Let’s just say that the CCR’s pace exceeded that slightly.  😉  While riding toward the Pisgah Inn the group came up behind a rider aboard a spanking new Hayabusa.  As Tom passed you could see him looking over in disbelief as the Bergman slid past, footboards dragging as the scooter leaned over into a right hand turn.  He shook his head as the rest of the group slipped by with a gentle wave.  Later as we were eating lunch the Hayabusa rider walked up to our table and started a conversation.  “How am I ever going to tell my buddies I got smoked by a scooter?”, he queried.  Tom simply responded “Don’t tell ‘em.”  I can’t say that was the most fun I’ve ever had on a CCR ride, but it was definitely the most memorable.  FEAR THE BERGMAN!!!!! Keep talking.  I’ll keep listening. Scott Cloninger General Partner Desert Desmo LLC Albuquerque, NM

Cast your votes!

Cage match is on! ONE VICTOR WILL STAND ALONE. Or some crap like that. We narrowed it down to 7 finalists, and we need help making the final decisions. Please cast your votes in the blog comment section. In no particular order... (photos should be clickable to get the full-sized versions where applicable) Mr. Bohnert's sunlit cruiser bohnert_1 Bryce's VFR, standing out in the crowd: bryce_1 Clay's flat tracker bringing sexy to the party: clay_1 Dan Yowell's R6/HDR: dan_yowell_1 Mr. Gillenwater's Maximus Veus: gillenwater_1 Kevin Kocher's traipsing 'Strominator: kevin_kocher_1 Will Munck's Painted Italian Water Monster: will_munck_1 What say ye...?

I present to you…

magna4... Erik Johnson's 1999 Honda Magna (4th or 5th generation, depending on whether you count the V30 and V45 as different generations). Why am I featuring this bike in this post today? Well, because he paid me $300 to do so*, and because I really, really enjoy these bikes. Back in 2004 (to early 2005,?) I had a 1995 Magna in that beautiful yellow, and to date it remains one of the bikes that look back upon, wistfully and longingly. I put maybe 10,000 miles on mine. magna1That generation of Magna was powered by the about-to-be-replaced VFR750 engine. The bike developed between 75 and 85 horsepower, and between 46 and 51 foot pounds of torque. Numbers vary as I suppose there were minor tuning variations between the years, and Honda has always been notoriously protective of engine performance specifications. Perhaps some values are measured at the wheel and some at the crank. Who knows... at any rate, the bike got down the road just fine. I won't say I won any races with mine, but it gave me quite a thrill riding it. Erik's bike looks like a very, very clean and well-kept example of what I consider one of the more understated and under appreciated machines on the road. While I typically prefer a solid-color paint scheme on most bikes, I like what Honda did with the graphics on the Magna... I guess it's meant to be a stylized flame or speed-induced striations. In any case, I like it. magna3The bike is pretty basic in appointments... drum rear brake, single disc front brake, very simple instrument cluster and a modicum of rider and pillion room. It's a fairly small frame bike, and at a little over 525 pounds wet and ready to ride, it's on the lighter side for something considered a cruiser. In typical cruiser fashion, the rider's legs are out front, but nothing I'd consider extreme. Not quite as far back as the Sportster's mid control configuration, but nothing stretched out like a Soft Tail or V-Rod, either. Call it "relaxed forward controls", if you have to call it something. I remember the handle bars being in a pretty neutral position, and honestly the only comfort and ergonomic modifications I made to mine were to install a very small shield and replace the stock seat. I had plans to take it on a solo cross-country trip... those plans never materialized during those years, but I felt the bike was fine for the job. I installed a set of Willie & Max synthetic leather saddle bags on a custom made aluminum rack I made, and had plans to install a Givi trunk on it... In fact, I still have the Givi E45 top case I bought shortly before selling the Magna. The VFR's engine was dressed with a bit of chrome, including chrome airbox covers, and the rest of the bike is decorated with enough functional chrome to stand out as nice looking without being gaudy. Erik keeps his looking much better than many I've seen; my wheels were never that clean. magna2I'm having some pretty serious knee issues these days, and keeping them tucked on the sportier bikes for any more than a half hour or so is all but impossible. I'm currently riding a VStrom by Suzuki, but if and when I decide to move to something that's more ergonomically friendly for my busted old bones, the Magna is on the short list. This generation of bike was built from 1993 (though marketed as an early '94) up through 2003 and remained unchanged, mechanically, through its life. The Magna was available in a variety of paint and graphic combinations throughout its run, including yellow, black, blue, red, purple   *No, Erik didn't really pay me $300 to feature his bike, but if he does, I'll be sure to let you know.

The Helmet Hook by eXtuff

If you're like me, when you just need to walk away from the bike for a few minutes you might often find yourself putting your helmet on your handle bar and checking it for stability 8 or 10 times before walking away, fearing the whole time that it will fall off and burst into a million pieces the second someone sneezes anywhere in the parking lot. Because of this, I usually just carry my helmet with me. Wouldn't it be nice to have a stable and trusted way of just hanging the helmet on the bike somewhere for a few minutes while you fuel up, get an ice cream cone or make a phone call? Well, now you can. Enter, the Helmet Hook. The Helmet Hook is, as the name might imply, a hook for your helmet. The hook is designed to bolt onto the handle bar end, between the bar and the bar-end weight. Most bikes these days have some sort of damping weight on the ends of the handle bars, so the number of bikes on which this *won't* work should be small and fleeting. hooks2To install the hook, you simply unscrew or unbolt your existing weight, slide the screw or bolt through the hook and reinstall the weight. The weight has a sizing washer in the center to help accommodate various mounting options across the plethora bikes and manufacturers. Take a look and send George a note if you like the product. The Helmet Hook product can be ordered directly from eXtuff's website and the price includes shipping. Paypal is accepted and should make for a very easy purchasing experience.

Notes on dry sump engines

Listener Stuart Watson sent us this email discussing dry sump engines, and their benefits and design details. Stuart pointed us at this link for more information. The majority of road bikes use wet sump lubrication, the ‘sump’ being a pan beneath the crankshaft where the oil is stored. A pump picks it up from here and forces it around the engine into the various bearings, spray jets and so on. After the oil has passed through the high pressure part of the system it drains back down into the sump purely under the influence of gravity. It’s simple and inexpensive, but there are disadvantages. The first is the size of the sump. Usually this will have to hold around 4 litres, maybe more. This is quite large – look at a 5 litre oil can to get an idea – and clearly it has to be at the lowest point, so the engine has to sit higher than might be ideal. Under hard acceleration or braking, or when the going is very bumpy, the oil in the sump can slosh around. In extreme cases this can mean the oil pump’s pick up tube becomes open to the air, and air bubbles are passed around the lubrication system, causing a lot of wear and damage. But it also means the oil can wash up against the crankshaft, which usually spins just above the surface of the sump oil. This causes a lot of drag, reducing engine performance as well as causing the oil to become foamy, which degrades its lubrication abilities.
The alternative is dry sump lubrication. Instead of storing the oil beneath the engine it’s kept in a separate tank somewhere else on the bike – in the frame on the Aprilia RSV Mille for example, or in the swingarm on air-cooled Buells. This means the engine can be positioned lower in the fraSemi_dry_sump_1me (very useful with naturally tall engines such as the V-twins mentioned), and the problems associated with oil sloshing around are eliminated. It’s easier to increase the oil capacity this way too, which means extended service intervals. The penalty is increased complexity (and hence cost), as you now need a separate tank and two oil pumps. One pump scavenges the oil draining down to the bottom of the engine and feeds it up to the oil tank, while a second, more powerful pump takes oil from the tank and feeds it back into the lubrication system under pressure. Some bikes though use a semi-dry sump system, including many off-road machines as well as the BMW. What this really means is that the system is to all intents and purposes a dry sump design, with two oil pumps, but the oil tank is still incorporated inside the engine cases. In the F800’s case it’s still stored beneath the engine, but not directly beneath the crankshaft. It’s a little more complex but by doing it this way the designers have more scope for lowering the engine and making it more compact.

RD350 restoration project by Motorcycle Girl

Celeste, aka the Motorcycle Girl has been restoring an RD350 street bike. Below you can find some text and pictures about her restoration. Give it a look. Celeste can be found on Facebook at https://www.facebook.com/celeste.atkinson.5.
I have not taken any recent pictures but enclosed is a link to the facebook album where I have posted some of them.  I bought it in several boxes and have been doing the ground up restoration over the last couple of winters.  The pic of the entire bike in the album is one that I found online so it is not my actual bike.  Tank and plastic parts are out getting painted as we speak and I hope to get the engine in the bike in the next couple of weeks. This model was never available in the US, only Canada so parts are more difficult to source locally.  Many of my parts have had to come from the UK where there is a cult following for this bike.  Interesting too is that Paul Manson(another listener) has one of these bikes too!
Pictures available at http://www.facebook.com/media/set/?set=a.412275535659.214893.692950659&type=3&l=26447bfedd

The Pace Motorcycle Podcast’s 2012 riding trip

Batten down the hatches and unfurl the sails... though, if your bike has hatches and sails, we want pics... and make way for the mountains. Nautical talk in the mountains, you say? On a motorcycle? What madness is this? The Adirondacks, son... and Lake Placid. Is Lake Placid even big enough for sailing ships? Who cares; we'll go, we'll ride, we'll party. That's right, the 2012 Pace Motorcycle Podcast's riding trip has been decided. We're doing the 'Dacks. Plan on a long weekend in and around lovely Lake Placid, New York, home of the 1980 Winter Olympics. The Adirondacks offer some wonderful scenery, some great riding, and a plethora of places to unwind after a day in the saddle. The trip is planned for a long weekend, July 27th through the 30th. Anyone wanting to join the ride up is welcome. We'll plan on leaving the Wilmington, Delaware area early on Friday the 27th, and arrive in Lake Placid in time for dinner. We'll be home-basing at the Econolodge in the town of Lake Placid. As the time draws closer, we'll be planning day-ride routes, group dinners and hopefully The Pace will be able to set up a few microphones and talk to some attendees. Please share your route and must-see destination ideas. Tracy Road is already on the list. So let's hear it - routes, restaurants, day-stops, overlooks, etc. What's on your list? Let us know at feedback@thepacepodcast.com.

A message from Chris Harr about Ricor suspension components

We got an email from long-time listener and guest on the show, Chris Harr. Chris wants to tell us about Ricor suspension components.
Hey Guys,
Do you read MCN? I ask because the back cover of a recent issue had a write-up on the Ricor Intiminators, a drop in compression valve/shim stack for damping rod forks which features an inertial valve which is intended to limit brake dive while also allowing effective high-speed bump absorption. In effect, the inertial valve allows the fork to have 2  different compression damping curves depending on which direction the suspension travel is occurring. The matching IAS Shock also has an inertial valve which affects rebound response instead of compression.
I did some homework on the KLR650.net, ADVRider and SV forums and found numerous positive reviews w/ no complaints, so I decided to give the Ricor parts a try.
I purchased the Intiminator fork valves and matching shock for my KLR in December under a winter special. The shock was shipped with a 300lb/ft spring which is on the soft side, but it seems to be working fine for me @200lbs in gear and with the panniers installed.
Install was straightforward. No modifications to the OEM damping orifices are needed, which means the forks can be returned to stock w/o replacement of OEM parts. I’d imagine you could install them w/ the forks in the clamps on the pre-08 KLRs but it’s better to remove them to drain the forks completely. The rear shock was also fairly easy  - the KLR’s upper shock mount nut is captive, which is a good thing since the airbox blocks direct access to it. Total install time with 2 guys working on the bike on a lift was about 2 hours. At home, I’d guess it’d take a half-day working solo, assuming you have the correct tools including an oil level tool for the forks.
I’ve had them in for a few weeks now and have logged around 500 miles since install.
In my opinion, the benefits of the combo are significant. The dive control under braking is really effective, but the forks are still fairly compliant over square-edged bumps. On local dirt roads I find that the front is far less scary over rough washboard/bumpy surfaces. Overall, the valves work exactly as advertised.
The shock is less cut and dry. The IAS system helps to slow forward pitch on the brakes relative to the OEM shock. Traction seems very good, even on wet and bumpy surfaces. The rear compression is stiffer than stock but it’s also less prone to bottoming. The improvement is definitely valving-related, as the 300lb/ft spring is only slightly stiffer than the OEM spring and I’m not running any more preload than I did with the OEM shock.
Where the IAS shock is strange, but effective, is over the wide speed bumps used in my local area. On the OEM shock, it would get launched out of the seat over those bumps at anything over 25mph (I can hit them much faster on the Aprilia BTW). The OEM shock simply had too little high-speed rebound to prevent kicking when most of the travel was used. The IAS shock exhibits far less of this behavior. The shock seems to extend quickly enough to track the back side of the speed bump as there is nearly no wheel spin after the crest of the bump, even at 45mph, but the kick is far less. Where it’s interesting is when the bike settles and then rebounds, it does so slowly and without a second or third oscillation.  To put it simply, the rear suspension seems to respond quickly when the rear suspension unloads over a bump, but rebounds slowly when dealing with chassis weight.
Compared to OEM, the bike is less pitch sensitive, less prone to bottoming, is slightly less plush over minor pavement imperfections, and is far easier to ride on bumpy gravel roads.
Post-sale, I’ve had a few questions or concerns. Brian @ Ricor has been responsive to my needs and has offered a spring rate change/revalve free of charge if needed (which I’ve decided it’s not). There may be limitations on those policies, but I’m still impressed with my interactions with their company.
Would I recommend the combo? Definitely, as long as the purchaser isn’t expecting KTM Adventure suspension quality… the kit on high-end dual sports is still superior to the modded KLR, but the gap is far less now and even with mods, I’m at ½ the cost of a used 950 Adventure and still less than the going rate for a used F650GS.
Chris, thanks for this excellent information!