| Author | Message | ||
     Diablobrian |
The single crank pin and side loading on the piston/cylinder is what really kills our motors, and prevents higher revs. | ||
| Blake |
I disagree, and I suspect that Buell will soon help prove it to you too.  | ||
| Blake |
Piston speed governs rev limit, no? | ||
| Blake |
Common crank pin does not affect piston lateral loading, yes? | ||
| Davegess |
"more cylinders with shorter strokes will mean more RPM'" True, although I doubt is anyone would make more cylinders and keep the same stroke for a given displacment, you would get some pretty tiny pistons! | ||
| Diablobrian |
Blake my point was an in addition to not an argument against. If each rod had it's own crank pin the stress on the crank could be distributed and each rod could have more beaing surface area. The press-in pin and knife and fork rods are not the strong enough to last long in high HP motors. (the new -silver- main bearings have been a great improvement in bottom end life) With the long stroke of our bike the rod deflects a long way out of alignment with the bore putting huge loads on the side of the piston and cylinder. If we didn't need the long stroke the side loading wouldn't be an issue, but to keep displacment the same the bore would be huge causing new and difficult problems with filling the cylinder, emptying it, flame fronts etc. Of course multi-cylinder arrangments with better primary balance would be be able to spin to insane speeds, but to keep them air cooled they would need huge fin surface and would be huge. Not to mention the fact the torque we know and love would be history in favor of the narrow top end power band that is so common in IL4 bikes. In short I agree with you Blake I was just adding embelishments  I just get sick of seeing the argument of displacement:hp between water cooled 4'sand air cooled twins (as I'm sure you do. | ||
| Ceejay |
Isn't that the point of the XBrr motor. shorter stroke, bigger bore, higher revs with the same piston speeds. with the I4's the pistons are traveling through the cylinder at almost two and half times more often than the twins in order to get more power output. That in of itself would dictate the use of water cooling. You can reduce rotating mass, piston weights, and even remove an oil ring, but you still have to combate the enemy of all rotating parts, friction, which in turn creates heat, which in an inline four-only two sides of the cylinder are in contact with air-a twin has all four(I know cylinders are round, thus they don't have sides) but I think you get what I'm saying Less surface area, less heat can be transfered to the air, and thus the need for water cooling in fours. What I don't know, or understand is why a longer stroke can't be introduced into the fours scenario. Does this cause an unwanted increase in piston speed? Does the motor just get to be too tall to fit into the bikes that seem to be getting smaller? I'm pretty sure that on the jump from a 600 to a 750 to possibly even a 1000 there isn't much difference in stroke, similar to the Harleys the cylinder size just gets punched out... | ||
| Diablobrian |
One thing to realize on the stroke and it's relation to piston speed is that the piston stops at both ends of the stroke and there is inertia involved. The larger (and heavier) the piston is the more inertia there is to overcome and more stress involved. The IL4 are oversquare (bore larger than stroke). This produces a high revving machine that will produce lots of HP up top. HP= (torque x rpm)/5252 An undersquare motor (bore smaller than the stroke) will rev lower and produce more torque, but it will not produce as much HP since that is a function of (determined via) rpms. There is of course a theoretical ceiling for piston speed I forget what it is exactly but it is in the neighborhood of 1000 fps (I could be off by a bit) bear in mind that the speed of sound is around 1100fps at sea level. I get your point with the sides and that is what both Blake and I were getting at with the size of air cooled IL4s. They need cooling fins (a lot of surface area) to cool the inside cylinders. Remember how big the old 1000cc A/C 1000s were? | ||
| Ceejay |
I think were looking at the same thing, I'm thinking of the old CBX-six across the front-man those things are wild looking! Where did they go and why? I think that is what the AMA is getting at also, yea your bike only has 600cc but it can hit 16000 of those in one minute, whereas a twin maybe can get 8000 of the 1350 in a minute, 9.6 vs. 10.8 respectively. Which shows that buell isn't too far off the mark in getting thier displacement and hp numbers to where they need to be for FX. Superbike isn't too far off, but I believe a lot more money would need to be thrown at it, more design work with the motor layout, testing, etc.... | ||
| Babyhuey |
its inevitable that buell and hd are going to both go with water cooling simply based on the fact that there are ever tightening epa regs on smog and noise levels.thats why hd never went with gear drive cams with their big twins.their riding right on the edge of the standards now.and i would think that a water cooled motor would be able to control cylinder/combustion chamber temps alot better,therefore enabling the motor to be tuned to a higher degree,obviously under the limits that the rotating assembly can handle.and i would disagree with the fact that a water cooled bike would be heavier,if they went through the hassle of re-engineering the motor to run water they would certainly throw that flywheel in the trash and save a boat load of weight. (Message edited by babyhuey on October 28, 2006) | ||
| Blake |
its inevitable that buell and hd are going to both go with water cooling simply based on the fact that there are ever tightening epa regs on smog and noise levels. Anyone care to dispel that myth for our fellow BadWeBr? Noise regs are ever-tightening? Tires already make more noise on most roads than anything else. | ||
| Blake |
Brian, If you take a look at the geometry of any motorcycle engine, I think you'll find that the piston rod geometry wrt off-axis angle of the rod and piston skirt loading is about the same as it is for our longer stroke Buell engines, on account of the piston rods for the short stroking engines are short. You have a point on the knife and fork situation in our current engines. My point is that there is nothing preventing that configuration from working very well if allowed to be redesigned. I give you the XBRR for instance. Who knows what the near future may hold. Will you be convinced if Buell releases a high revving 120 RWHP model that employs a single crank pin? I think what you are saying is that some of Buell's competition provide engines that are better suited to the combination of major performance enhancement and the rigors of racing. No doubt. | ||
| Justin_case |
ALL H-D cams are gear-driven. | ||
| Court |
>>>its inevitable that buell and hd are going to both go with water cooling simply based on the fact that there are ever tightening epa regs on smog and noise levels. That's an inaccurate statement. EPA regs are not even on the Buell radar screen. The current iteration already passes the next several years of "reg tightening". Buell will have some significant developments. They will respect the regulations, they will not be driven by them. | ||
| Justin_case |
Disregard my previous post. Was thinking Sportster vs. Evo Big Twin. Twin Cams are,of course,chain driven. | ||
| Trojan |
That's an inaccurate statement. EPA regs are not even on the Buell radar screen. The current iteration already passes the next several years of "reg tightening". Buell will have some significant developments. They will respect the regulations, they will not be driven by them. How will they fare with the new Euro 3 regulations coming into force over here across the pond? If Honda and some of the other manufacturers have had to shelve some relatively modern engines to get through these regs then I would assume that Buell/H-D would have to do some work. Not a criticism by the way, I would just like to know how they are going to address these issues? | ||
| Ft_bstrd |
Do we really want to introduce a brand new engine design at this point? ALL new designs have a "real world" learning curve with regards to reliability and gremlins. Now that Buell is beginning to develop good dependable bikes (yes, I know there are some who have had problems, but as a whole nearly all of the press feel that the XB has been a reliable platform), do we really want to introduce ANYTHING that would decrease reliability NOW? I don't care how much R&D you put into a brand new product, the "real world" test will always reveal design flaws and weaknesses. I seriously doubt anyone believed that the Uly would be used like this on a regular basis:  EVERY new product, first year product, has problems. The question is whether that problem is going to be major or minor. Each successive year brings enhancements, modifications, and updates on the original design as a result of "real world" experience. Check a car model time-line. Each year there is a complete list of changes made from year to year. Face it guys, we ride them harder, longer, faster, and more often in environments testers failed to anticipate. Or if it was anticipated, the statistical frequency was expected to be lower. A water cooled bike would be cool someday, but I would rather wait until the Buell is more established and a few "growing pain" years won't be deemed as "There's another piece of crap Buell with mechanical problems. They're made by Harley Davidson, you know." If that happens, you may get to buy the water cooled engine ONLY in the final model year Buell. Besides, we haven't even begun to fully exhaust the potential of our "old tech" lump. | ||
| Anonymous |
Since Euro 3 comes into effect in '08, you can bet the solution is already booked, Trojan. And it doesn't require much. Since we were already able to pass Euro 2 and '08 CA without even a small Cat, why would people think we couldn't pass Euro 3? Why did Honda and others have to shelve "modern" engines? Well, I'd have to say that "modern" in the case of these engines might be very questionable. By definition, wouldn't the engine that is able to be sold in '08 be more modern than one that isn't? Unless "modern" counts number of valves and/or cylinders and/or parts, and I can't find that requirement in the definition of "modern". | ||
| Diablobrian |
Blake, I'm pretty satisfied with my current engine Yes, there is room for improvement in the rod and crank design that is currently in use. Even the XBRR has a rev ceiling very close to what our stock bikes run, if you want it to have a reasonable life span. The top end has been solid on the XBRR it has been the bottom end that has caused BMC so many headaches this year. I would love to see what the elves could come up with if allowed a clean sheet design a new motor. What configuration, # of cylinders, bore, stroke, and displacement would they choose if the sky was the limit? Erik has already stated a preference for air cooling so I would assume that to be a given. | ||
| Trojan |
Since Euro 3 comes into effect in '08, you can bet the solution is already booked, Trojan. And it doesn't require much. Since we were already able to pass Euro 2 and '08 CA without even a small Cat, why would people think we couldn't pass Euro 3? Why did Honda and others have to shelve "modern" engines? Well, I'd have to say that "modern" in the case of these engines might be very questionable. By definition, wouldn't the engine that is able to be sold in '08 be more modern than one that isn't? Unless "modern" counts number of valves and/or cylinders and/or parts, and I can't find that requirement in the definition of "modern". Sorry, what I meant by 'modern' engine was one designed in the last few years or so, such as the CB500 twin (yes I know it is based on an older engine) and other similar motors that have now been discontinued as a direct result of the Euro 3 regs apparently. Like I said, this isn't criticism, just a legitimate question so please don't get defensive. BMW and MOTO Guzzi will have the same problems to deal with with their air cooled motors too and I was just wondering how it would effect Buells direction and sales in Europe. Does it mean that catalytic convertors will be seen on new models? Will we see a 'lean burn' or 'liquid' cooled motor any time soon? | ||
| Diablobrian |
Buell still has the option of simply adding a catalytic converter. They unlike the others mentioned haven't needed one yet. | ||
| Jlnance |
Sorry, what I meant by 'modern' engine was one designed in the last few years or so, such as the CB500 twin (yes I know it is based on an older engine) and other similar motors that have now been discontinued as a direct result of the Euro 3 regs apparently. Here is my guess. I suspect that the engines you refer to are designed primarily to be race engines. Of course they have to run on the street, but the marketing used to push the bikes is that you can own the same bike that won the daytona 200. The homogulation requirements mandate that the bikes used in the races must have very similar engines to the ones available on showroom floors. There is no reason why an engine designed for good race performance would have good emissions performance. | ||
| Jlnance |
Noise regs are ever-tightening? Tires already make more noise on most roads than anything else. When I ride my Uly over to see Sportymark, he doesn't hear the engine when I pull up. He knows I'm there because he hears the fan. Seriously. | ||
| Court |
>>>The question is whether that problem is going to be major or minor. I suppose it'd be hard to refute that but the first year "Glitches" (with due deference) in the Ulysses have been very minor. The other day, when someone mentioned to me that they were going to trash their Ulysses in favor of a Triumph Sprint, I popped on over the the NHTSA recall homepage. I'll let you draw your own conclusions. I understand that no issue is small when it's YOUR issue. But I'm really proud of the Ulysses. The first year busts have not only been relatively minor, but Buell's shown an amazing willingness to respond quickly with solutions. Erik has stated an affinity for air cooling in the past. Knowing him I'd chalk that affinity up to simplicity rather than blind allegiance to team colors. Erik HATES extra parts. Look closely at your Buell and note the examples of one fastener doing several jobs. If you are a platform engineer and want to add a part to a bike, you better be able to justify it. I expect some exciting developments from Buell. In my personal opinion, it's damn near impossible to get that many well educated smart people working in an enviroment that fosters imagination and creativity and NOT expect something neat. Cool beans. . . . to me. | ||
| Blake |
Matt, The conventional wisdom holding that air-cooled engines are somehow at a disadvantage versus liquid-cooled engines when it comes to meeting anti-polution requirements is a complete and utter myth with absolutely zero factual basis. What do you imagine would cause an air-cooled engine to suffer such a disadvantage? | ||
| Rocketman |
Mechanical noise. Intake noise. Exhaust noise. Rocket | ||
| Diablobrian |
Intake and exhaust noises are managed through baffling the same as on a liquid cooled motor. Mechanical noise is a very real issue, but it is one that hasn't caused undue trouble for Buell.....yet. Quieter transmission gears have recently been introduced as one answer to that problem. I'm sure others are in the works. | ||
| Blake |
Sean, If you were intending to answer my question, you no read good. | ||
| Reepicheep |
Loud Fans Save Lives! (though they do annoy the hell out of Ferris ) | ||
| Ft_bstrd |
Have you guys heard a new Uly? Holy crap, when they started it up you couldn't hear anything. I added the race can because I wanted it to sound like a motorcycle. It was too quiet. Court, I agree completely that the issues with the ULY, for a brand new design, have been minor. New model issues, not just Buell, have with some manufacturers been gigantic and catastrophic. Just ask Nissan. Here in TN, you can find an endless parade of Altima 2.5s heading down 840 to the plant in Smyrna. Why? They have such a bad engine problem that ALL of that model are being recalled to replace the rings I thing. That to me is major. Everything so far on the Uly has been minor (and I would buy it again in a heartbeat!). |
