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From: Thumper on 14 Jun 2007 14:24 "Rayvan" <rvannuland(a)cachevision.com> wrote in message news:1181842446.926195.61960(a)i13g2000prf.googlegroups.com... > On Jun 14, 7:16 am, "Dave" <dspear9...(a)yahoo.delete.com> wrote: > >> not for the "cool sound"? Interesting that Suzuki can get 153HP out of a >> 1300cc motor which is relatively quiet while HD struggles to get 100HP >> and >> only then with incredibly expensive mods and a sound that, according to >> another post, will "wake the dead". > > Yeah, well. HP isn't everything. Some of us just don't like cheap- > plastic throw-away bikes that cost way too much to maintain and sound > like a sewing machine. > -- > Rayvan Sew you don't like BMW's? Thumper >
From: Dave on 14 Jun 2007 14:30 "Thumper" <roadapple(a)unclewebster.com> wrote in message news:XKfci.403$W_6.234(a)newsread1.news.pas.earthlink.net... > worry, it's metal underneath. > > Sheesh, what a snob. > > Ouch.
From: Albrecht via MotorcycleKB.com on 14 Jun 2007 14:36 Dave wrote: >For the record, it was the guy that wrote about the physics of muffler >construction and the unreasonable volume of muffler that would be required >to muffle a large twin that I found the most convincing. Well, the assertion that a quiet muffler for a Harley needs ten gallons of volume was hyperbole, you could probably make a nice quiet muffler for a Big twin using only five gallons of volume. That's still a huge muffler, it's 7 inches in diameter and 30 inches long and would look about right underneath a car. > FINALLY an actual >reason... of course why would you design a motor that can't be muffled if >not for the "cool sound"? The Harley exhaust rumble is an accident that is caused by the dual fire ignition system on carbureted models. The coil fires a "waste spark" when the exhaust valve is open and that ignites any mixture left in the exhaust pipe which is rich enough to burn. An ignition system that fires a waste spark is not unusual, many Japanese motorcycles use twin lead coils and make a rumbling sound in the exhaust pipes. The potato-potato-potato sound a Harley makes is due to the firing order. One cylinder fires, then the other fires 45 degrees later and then there are 675 degrees of crankshaft rotation until the next power stroke. It takes 720 degrees of crankshaft rotation to fire both cylinders, and, if you roll off the throttle, you will hear the typical Harley gear whine as it slowly coasts down. Harley selected that firing order because the V2 engine was smoother running than a 360 degree vertical twin which was always on opposite strokes as both pistons rose and fell together like the old Triumphs, Nortons and BSA's. The alternative to a 360 degree vertical twin was a 180 degree vertical twin where the cylinders fire 180 degrees apart. Honda developed those engines in the 1960's. The cylinders fire 1, 2 and then the crankshaft has to coast for 540 degrees. The dirt track riders claimed that was better for traction, but other dirt riders would re-arrange their 360-degree crank engines to fire both cylinders at the same time, and that was called a "twingle". Nowadays, Triumph is building vertical twins that have 270 degrees between firing strokes and the engine coasts 450 degrees. Triumph seems to have gotten the firing order from Yamaha's TDM850 that used a 270 degree crankshaft to emulate Ducati's power delivery. > Interesting that Suzuki can get 153HP out of a >1300cc motor which is relatively quiet while HD struggles to get 100HP and >only then with incredibly expensive mods and a sound that, according to >another post, will "wake the dead". The issue of why inline-4's are so quiet compared to other designs also comes up when people ask why Ducatis have to be so loud. It's the relative volume of the cylinders and the firing order. There are smaller pulses of exhaust gas coming down the exhaust header, but they are coming much more often, and the pressure waves run into each other as they reflect off the walls of the muffler and all that sound energy gets absorbed instead of flying out the exhaust pipe to rattle off the concrete canyons at midnight. -- Message posted via MotorcycleKB.com http://www.motorcyclekb.com/Uwe/Forums.aspx/bike/200706/1
From: Road Glidin' Don on 14 Jun 2007 14:54 On Jun 14, 12:20 pm, "Dave" <dspear9...(a)yahoo.delete.com> wrote: > "Rayvan" <rvannul...(a)cachevision.com> wrote in message > > news:1181842446.926195.61960(a)i13g2000prf.googlegroups.com...> On Jun 14, 7:16 am, "Dave" <dspear9...(a)yahoo.delete.com> wrote: > > > Yeah, well. HP isn't everything. Some of us just don't like cheap- > > plastic throw-away bikes that cost way too much to maintain and sound > > like a sewing machine. > > -- > > Rayvan > > I've got a '73 Honda CB750K3 in my garage with more than 80,000 miles on it. > I'd say that'd beat out 99% of the bikes on the road for longevity. Must not be a fun bike to ride then. My Road Glide's got way more miles than that on it and it's only a '98. > And cost, come on let's be serious! Are you saying HD's tend to be cheaper > to purchase, insure, maintain or repair? What kind of joke is that? That only joke is people parroting things they've heard and want to believe - pretending to know something, but having no experience of what they're talking about. > My '99 VFR800FI has gear-driven cams and I love the sound... now that you > mention it it DOES sort of sound like a sewing machine 'till you wind it up. > Oh, and a previous owner took all the plastic off (with no tools!) except > for the windscreen... don't worry, it's metal underneath. Well, a big whoop-dee-doo for you, Ace.
From: Dave on 14 Jun 2007 14:57
"Albrecht via MotorcycleKB.com" <u33665(a)uwe> wrote in message news:73b2d13860b1e(a)uwe... > Dave wrote: > > > Triumph seems to have gotten the firing order from Yamaha's TDM850 that > used > a 270 degree crankshaft to emulate Ducati's power delivery. > > The issue of why inline-4's are so quiet compared to other designs also > comes > up when people ask why Ducatis have to be so loud. > I've got a Yamaha 650 Custom (XS650) vertical twin which I rarely ride as the vibration is awful at highway speeds. Yamaha's answer was to put squishy rubber bushings between the bars and steering tube which makes for a real sloppy feel. And it still vibrates like a mo-fo. I really can't figure out WHO would seek out this bike and buy it other than those nostalgic for the look of the old Triumph Bonneville. I inherited mine from an older relative who no longer rides. Do you know the firing pattern on this bike? I'm curious about it. My brother-in-law has two Ducatis, a Monster 620 (parts bike after last weekend) and a Multistrada 620, same 618cc 90-degree v-twin in both. They don't seem that loud to me and I've ridden behind him lots. Maybe I just can't hear it over the roar of my sewing machine... Dave S |