New member, figured I'd show what I found found for $1,700.00 CA. Put a few personal touches on it. Required no engine work.
- Thread starter gtatt85
- Start date
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Looks like an '85.
Does it run? Because if it does, and you've ridden it enough to hit VBoost a few times, when you replace the Cobra exhaust with a stock one, it's gonna be a whole 'nother ballgame. You're riding a 'hobbled horse' there. Do yourself a favor and search on here for 'cobra exhaust,' and read the threads.
After that, consider the addition of, instead of an OEM exhaust, a 4/1 from almost anyone. That, and a jet kit. Typical ones to read-about (yes, the 'search' function, again) are the Dynojet Stage 7 or the Morley's Muscle kit. Properly tuned, either of those w/the 4/1 exhaust, should put you right around 120 RWHP. With a pretty-but-dysfunctional Cobra four-into-four exhaust, your power output is 'way-down from stock, and is double digits instead of ~110 RWHP which is typical of a OEM without jetting & exhaust. FYI, replacing the Cobras with another aftermarket 'slip-on' exhaust, like a 4-into-2, will probably restore the power to OEM-levels, but that style, the 'slip-ons,' which retain the OEM headers, but replace the stock twin megaphones and the resonator box which is a single piece, will not increase the bike's rear-wheel horsepower (RWHP) beyond the stock component's level.
Does it run? Because if it does, and you've ridden it enough to hit VBoost a few times, when you replace the Cobra exhaust with a stock one, it's gonna be a whole 'nother ballgame. You're riding a 'hobbled horse' there. Do yourself a favor and search on here for 'cobra exhaust,' and read the threads.
After that, consider the addition of, instead of an OEM exhaust, a 4/1 from almost anyone. That, and a jet kit. Typical ones to read-about (yes, the 'search' function, again) are the Dynojet Stage 7 or the Morley's Muscle kit. Properly tuned, either of those w/the 4/1 exhaust, should put you right around 120 RWHP. With a pretty-but-dysfunctional Cobra four-into-four exhaust, your power output is 'way-down from stock, and is double digits instead of ~110 RWHP which is typical of a OEM without jetting & exhaust. FYI, replacing the Cobras with another aftermarket 'slip-on' exhaust, like a 4-into-2, will probably restore the power to OEM-levels, but that style, the 'slip-ons,' which retain the OEM headers, but replace the stock twin megaphones and the resonator box which is a single piece, will not increase the bike's rear-wheel horsepower (RWHP) beyond the stock component's level.
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Awesome, thank you for that reply. Will definitely be trying to find the kerker 4-1 if I have any luck.
Nice find!
Ditto on all accounts
Question, I am wondering why the slash cuts are soo much down on power, is it back pressure?
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A guy had them on here in Denver, tried to tune his way into a decent runner and was bitterly disapointed.
They sounded great, looked good too but just could not pull hard in all ranges.
They sounded great, looked good too but just could not pull hard in all ranges.
Exhausts are tuned for an 'extraction effect.' One cyl's exhaust pulse fires before another's, and the second exhaust pulse is pulled-along by the first-firing exhaust ahead of it where the two exhaust pipes merge together. Basic physics, matter moves from an area of higher concentration to an area of lower concentration. The length and the size of the pipe's diameter causes high and low-pressure waves which occur at different rpm's. Manufacturers have used exhaust valves like Yamaha's EXUP system to vary the volume of the exhaust to create favorable use of the pressure waves, just as they use stepper motors to vary the length of the inlet side to promote better power or torque.
In a two-stroke 'tuned' exhaust, the high-pressure waves 'push-back' the exhaust charge towards the cyl head/combustion chamber, helping fill the exhaust chamber with unburned gas so that it can ignite when the piston(s) rise to TDC. Because a two-stroke has no intake or exhaust valves, and relies upon ports in the cyl sides to allow the flow of gas/oil mixture in and out of the combustion chamber, they are inefficient in burning the volume of gasoline they use. The use of rotary valves was one way by which two-strokes could keep the gas charge from flowing out the exhaust port
For a great read on how this was discovered, read Stealing Speed, available on Kindle.
https://www.motorcycleclassics.com/classic-german-motorcycles/suzuki-ernst-degner-ze0z1202zsch/
It's a great story of motorcycle racing, industrial espionage, and post WWII engineering advancements in Grand Prix motorcycle roadracing.
In a two-stroke 'tuned' exhaust, the high-pressure waves 'push-back' the exhaust charge towards the cyl head/combustion chamber, helping fill the exhaust chamber with unburned gas so that it can ignite when the piston(s) rise to TDC. Because a two-stroke has no intake or exhaust valves, and relies upon ports in the cyl sides to allow the flow of gas/oil mixture in and out of the combustion chamber, they are inefficient in burning the volume of gasoline they use. The use of rotary valves was one way by which two-strokes could keep the gas charge from flowing out the exhaust port
For a great read on how this was discovered, read Stealing Speed, available on Kindle.
https://www.motorcycleclassics.com/classic-german-motorcycles/suzuki-ernst-degner-ze0z1202zsch/
It's a great story of motorcycle racing, industrial espionage, and post WWII engineering advancements in Grand Prix motorcycle roadracing.
You will need earplugs to use that system. That, or swap-on a more-restrictive exhaust canister. That's what I did with my Dragstar. Mine is an older system, which had little in the way of baffling, the current one looks like it may provide a bit of relief in sound output. I bought the megaphone exhaust similar to what's pictured to replace the shorty/stubby exhaust tip, and it was still loud, but it was a bit quieter.
https://starriderperformance.com/dr...phone-muffler-black-ceramic-coated-85-07-all/
The Quad-Zilla by the same company is another hellaciously-loud system, but it offers the performance the Cobra 4-into-4 system doesn't deliver. StreetPro 4-2-4 Exhaust w/ Polished Quadzilla Mufflers - Ceramic Coated (85-07 All)
Thanks for this. Would definitely like to get as much out of it as I can.
one2dmax
Well-Known Member
Any full system will perform well enough that one brand isn't "better" then another. I've got a number of used options and some new options (though new is dwindling down as they quit making them). The slip-ons don't add power (since they don't repalce the small primaries) and the cobra's lose the ability to scavenge.
ouchez
Well-Known Member
Looks great!
ouchez
Well-Known Member
I think "Marks" is the best exhaust over all, find one of those or go back to all stock. IMHO.
O
FM, I and about a hundred other guys here would love to sit down with you and a cold beer and just chat about all things mechanical.....
You have a fascinating wealth of knowledge!
I think we're lucky to have your contributions to this forum.
Thank you Fire-medic
Gent
gentsvmax, from reading your frequent posts, I think you may exceed my knowledge mechanically. Like many others I started riding trikes, then bikes, and since we lived on a hill, we made push-carts, and raced each other down the hills in the neighborhood. With older brothers having Jaguar and Triumph sportscars, and American V8 4-speed cars, and a 1960's Honda bike, I was introduced to OHV, DOHC, SOHC and yes, flatheads. My father knew I was interested in sportscars, and Detroit V8 iron, and he used to bring all the magazines of the day home for me, after one of his co-workers read them, and he sent them 'for your son.' I was happily reading what became Car and Driver, which was first Sports Cars Illustrated. There was Sports Car Graphic, which had lots of focus on the road courses around the country, and along with Road & Track, many technical articles about engines, suspensions, styling, and various types of competition. Quarter-mile, oval (dirt and paved) in short and long distances, road courses both dedicated and public roadways, Bonneville salt flats, and rallies: the MI Press On Regardless and Monte Carlo, and many others.
Then there were the personalities. Engineers, CEO's before that was a familiar phrase, Henry Ford, George Selden (he held a patent on the automobile, until in a long-fought battle, Henry Ford broke his patent), Henry Duryea, Karl Benz, who named his corporation after his daughter, Mercedes; William Crapo Durant (the head of GM), Charles F. Kettering, of DELCO, who brought to market the electric self-starter (before that, compressed air was how some manufacturers started their automobiles) and the octane-increasing chemical added to gasoline, tetraethyl lead, unknown then was the cumulative effects of it in the environment, and its carcinogenic properties. The tire pioneers: Dunlop (the pneumatic tire), Goodyear (vulcanizing) and Firestone (for decades, the dominating tire at the Indianapolis 500), Chadwick, who developed supercharging of engines from a mine ventilation system; Peugeot, who developed the DOHC engine; Fred Duesenberg, first production use of hydraulic brakes, developed by Loughead (changed to Lockheed for marketing purposes), and Crosley for introducing disc brakes in the post-WW II era. Edwin Turner for designing the Triumph Speed Twin, and before that, a new four cyl. motorcycle engine no one was interested in until British manufacturer Ariel agreed to produce it, they called it the Square Four.
Out of the ashes of vanquished Japan, Honda produced piston rings, and then motorized bicycles, and after being introduced to W. Edwards Deming, who developed a method of 'building-in' quality instead of using quality control people to look at finished products for faults; Demings' idea was 'Total Quality Management.' He had tried to interest USA manufacturers in the concept, but was rebuffed. The Japanese adopted it, and 'made in (Occupied) Japan' went from a sign of cheaply-made products to 'made in Japan' meaning quality, innovation, and industry-leading products distributed worldwide, and dominating in the markets they researched and planned-for. Sony, Marantz, Sansui, Crown, Pioneer, Olympus, Nikon, Canon, Minolta, the Big Four (Honda, Yamaha, Kawasaki, Suzuki), and starting in the 1960's, Toyota, then Honda, in the 1970's, Mazda & Mitsubishi. And so it continues.
John Cooper who competed in small-displacement open-wheeled events in the UK, using single-cylinder motorcycle powerplants, and portable London Fire Brigade fire pump engines (DOHC Coventry-Climax) placed behind the driver! He changed racing forever. Alec Issigonis, the FWD-two-box Mini, making an industry adopt his design and so-important to a nation's economy, he was knighted by Queen Elizabeth II. Nearly every automobile manufacturer competing in the lower-priced segment of the world market had to adopt the design.
I bet it comes as no-surprise to many reading this far, that two of my favorite authors to read about transportation and engineering are Peter Egan and Kevin Cameron. From their personal experiences, their list of friends and acquaintances, and their garage and house contents, they write about things which increase the reader's knowledge of engineering, transportation, and the mores and folkways which society has.
There are hundreds more people to mention, companies to discuss, engineering principles to study, and subjects not yet broached. Another time, and here and elsewhere. Spread your knowledge, share your passions, and pass it all on to succeeding generations.
Then there were the personalities. Engineers, CEO's before that was a familiar phrase, Henry Ford, George Selden (he held a patent on the automobile, until in a long-fought battle, Henry Ford broke his patent), Henry Duryea, Karl Benz, who named his corporation after his daughter, Mercedes; William Crapo Durant (the head of GM), Charles F. Kettering, of DELCO, who brought to market the electric self-starter (before that, compressed air was how some manufacturers started their automobiles) and the octane-increasing chemical added to gasoline, tetraethyl lead, unknown then was the cumulative effects of it in the environment, and its carcinogenic properties. The tire pioneers: Dunlop (the pneumatic tire), Goodyear (vulcanizing) and Firestone (for decades, the dominating tire at the Indianapolis 500), Chadwick, who developed supercharging of engines from a mine ventilation system; Peugeot, who developed the DOHC engine; Fred Duesenberg, first production use of hydraulic brakes, developed by Loughead (changed to Lockheed for marketing purposes), and Crosley for introducing disc brakes in the post-WW II era. Edwin Turner for designing the Triumph Speed Twin, and before that, a new four cyl. motorcycle engine no one was interested in until British manufacturer Ariel agreed to produce it, they called it the Square Four.
Out of the ashes of vanquished Japan, Honda produced piston rings, and then motorized bicycles, and after being introduced to W. Edwards Deming, who developed a method of 'building-in' quality instead of using quality control people to look at finished products for faults; Demings' idea was 'Total Quality Management.' He had tried to interest USA manufacturers in the concept, but was rebuffed. The Japanese adopted it, and 'made in (Occupied) Japan' went from a sign of cheaply-made products to 'made in Japan' meaning quality, innovation, and industry-leading products distributed worldwide, and dominating in the markets they researched and planned-for. Sony, Marantz, Sansui, Crown, Pioneer, Olympus, Nikon, Canon, Minolta, the Big Four (Honda, Yamaha, Kawasaki, Suzuki), and starting in the 1960's, Toyota, then Honda, in the 1970's, Mazda & Mitsubishi. And so it continues.
John Cooper who competed in small-displacement open-wheeled events in the UK, using single-cylinder motorcycle powerplants, and portable London Fire Brigade fire pump engines (DOHC Coventry-Climax) placed behind the driver! He changed racing forever. Alec Issigonis, the FWD-two-box Mini, making an industry adopt his design and so-important to a nation's economy, he was knighted by Queen Elizabeth II. Nearly every automobile manufacturer competing in the lower-priced segment of the world market had to adopt the design.
I bet it comes as no-surprise to many reading this far, that two of my favorite authors to read about transportation and engineering are Peter Egan and Kevin Cameron. From their personal experiences, their list of friends and acquaintances, and their garage and house contents, they write about things which increase the reader's knowledge of engineering, transportation, and the mores and folkways which society has.
There are hundreds more people to mention, companies to discuss, engineering principles to study, and subjects not yet broached. Another time, and here and elsewhere. Spread your knowledge, share your passions, and pass it all on to succeeding generations.
