Cobra Pipes and jetting.

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kwarnke

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this is the newest member to my toys but the guy had no clue what he had. the bike runs rough...period. I keep reading that it needs to be jetted with the Cobra pipes. I know a little loss of power but its a Vmax and im 52, I dont care. Thoughts?
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sdt354

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this is the newest member to my toys but the guy had no clue what he had. the bike runs rough...period. I keep reading that it needs to be jetted with the Cobra pipes. I know a little loss of power but its a Vmax and im 52, I dont care. Thoughts?
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I wouldn't bother. Unless the carbs needed a redo. Then I'd put 150's or 147.5 mains in. The longer I own mine the more I want some punch when I crack the throttle. 52? Still a kid.
 

Fire-medic

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Cobras are for looks, not performance. Soggy throttle response, VBoost that doesn't, not-like OEM; a reduction in power to double digits instead of customary triple digits in OEM jetting & exhaust, what's to like about them? If you ride a totally-stock bike and compare it to your bike's performance, it makes you wonder, "why would anyone do this to their bike?"

You can search on here for this as a topic of discussion, and other than appearance, there isn't any reason to use them. Especially on a bike that was the quickest of its time.
 

Parminio

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There is no such thing as jetting for Cobra pipes. It doesn't matter what you do, you're really not going to get decent performance out of them.

Get a decent set of pipes BEFORE you even bother messing with your carbs.

Trying to improve your performance with Cobra's on the bike is, quite literally, an exercise in futility.
 

Smithjs35

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Ditched my Cobra's and returned to stock muffler. No more backfiring and a totally different motorcycle. V-boost came alive, almost like it had been hibernating with the Cobra's. Rear tire breaks lose so easily. I love that the vmax is so quiet now but, twist the throttle a little and it comes alive. Thanks so much for all your help, Vmax forum, especially one2dmax and fire-medic.
 

Parminio

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Glad you got it sorted, man.

It's a shame too. Cobra's, in my humble opinion, are by far the best looking pipe you can put on a Vmax. But good, great, merciful God they flat out SUCK performance wise.
 

Fire-medic

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Merchandising is what makes a product. Not everyone needs what a VMax can do, stock. Someone may want the looks and the performance reduction makes it more-usable for them. They aren't afraid that the bike will bite 'em.

Thinking back to the H1 Kawasaki, when it was released in 1969, it immediately got a reputation as a contributor to hospital E.R.'s and burial plots. If they had just pulled-off one of the three spark plug wires, before turning-loose on the streets the proud new owners of the white menace (it also had a charcoal color) a lot of people might have been saved from harm. That's kinda what Cobras do.

I had a '71 H1 back in the early '70's, and it was a lot of fun, I enjoyed spoiling my roommate's feelings of grandeur over his brand new 1,000cc Sportster.
 

user 76942

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Ditched my Cobra's and returned to stock muffler. No more backfiring and a totally different motorcycle. V-boost came alive, almost like it had been hibernating with the Cobra's. Rear tire breaks lose so easily. I love that the vmax is so quiet now but, twist the throttle a little and it comes alive. Thanks so much for all your help, Vmax forum, especially one2dmax and fire-medic.
I bought my max with Cobras on it. It runs smooth and at 73 I don't know if it would be beneficial to change. Exhausts are so expensive. I've had an H1 Kaw and a z1900 Kaw. I loved them both. z1 900 (75) Unfortunately was stolen. I just sold my 79 shovel. Love to go fast still. Reflexes are not as good as they where. Vmax reminds me of my old z1.
 

Fire-medic

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I bought my max with Cobras on it. It runs smooth and at 73 I don't know if it would be beneficial to change. Exhausts are so expensive. I've had an H1 Kaw and a z1900 Kaw. I loved them both. z1 900 (75) Unfortunately was stolen. I just sold my 79 shovel. Love to go fast still. Reflexes are not as good as they where. Vmax reminds me of my old z1.
Replace your shiny Cobras with an old, scabby OEM Yamaha exhaust, and I guarantee your bike will perform like you've never-experienced! Literally not the same bike! But it is, except for the exhaust, and if they changed anything in the carburetors and intake system. Changes made are easy to discern.

Of course, the bike will appear much-better with an unblemished OEM exhaust. The point is, you won't believe that your bike had all that performance hiding behind a Cobra 4/4.

If you are an old guy, and from your self-report you are, it is akin to riding a Super 90 SOHC Honda single-cylinder, and then being handed the keys to a 1966 'turtle-tank' DOHC parallel-twin four-stroke Honda 450, and being told, "be sure to hit redline before you shift!." Literally a world of difference. FYI, the DOHC Honda 450 parallel-twin was banned from competition in the U.K. even though the Daytona 500 OHV T100R Triumph parallel-twin was larger displacement, and factory racers based upon it won the Daytona 200 roadrace in 1967. Another T100R rider came-in second. For good measure, another Daytona T100R Triumph 500 OHV twin won in 1966. (Buddy Elmore)

1642017840886.png

"Hey, Niner!" That would be Gary Nixon (winner Daytona 200 1967).
 
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user 76942

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what would be a good reasonable price for an oem exhaust? Thanks for your great answer!!
 

Fire-medic

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Coincidentally, CaptainKyle [email protected] is someone to whom I would refer you.

Sean Morley [email protected] is another.

I'd suggest $200 to start on ebay for the Cobra 4/4's. You want to get off them. Ad should contain, "Most-beautiful full exhaust ever for a Generation 1 & blowout pricing!"
 
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Parminio

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Most OEM pipes I've seen go for 250 to 350.


 

Smithjs35

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My 2000 Carbon had Cobra's on it when I purchased it and they sound / look really good. It was a big undertaking to go back to stock, more than I realized, the parts needed ie, muffler stay with its grommets, sleeve nut, bolt and washer were extremely hard to find. But I got a great deal on a beautiful 46 lb. muffler that was I believe to be powder coated and in close to new condition from a forum member from Canada for $130 plus shipping ($125) for expedited. But the best part was the V-boost came alive earlier thus longer. And I am pleased to hear / feel things that you could not previously. Also thankful for the forum and its members, especially one2dmax, fire-medic and parminio. I would have taken a lot of wrong turns without you guys.
 

Fire-medic

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Every time you see a 'newbie' sporting the performance-killing Cobra 4/4's, you should post him a link to this (your post #18 in this thread).

I have to admit, there are those who 'march to the beat of a different drummer.' The Harley-Davidson guys go nuts for Knuckleheads, and this artist's version of one must give them apoplexy. Infamous, notorious Grayson Perry.

H-D Knucklehead Grayson Perry.jpg
 

TheFleshRocket

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My first Vmax, a '98, had Cobras with punched out baffles. They were ear-bleedingly loud. IIRC, I replaced them with stock mufflers, which I drilled five holes in each exit area for more noise. I don't recall there being a significant change in performance (improvement or otherwise) going back to the stocker. Then I lowsided the bike, and replaced the stock mufflers with some Jardine slipons, and I don't recall any noticeable performance change there, either.

This is in stark contrast to my Gen2. I replaced the stock converter with an Optimal Carbone converter-delete x-pipe (which I have in my garage.. and is unofficially for sale) and a Guru tune, and I don't remember it being a huge difference. Like, it was a bit stronger, but not OMG awesome. Then I bought a Hindle 4-1 full system, and holy crap, the bike must have picked up 15whp. Suddenly it's very noticeably quicker, and will even power-wheelie first gear. Not a huge wheelie, probably only like six inches or a foot, but it happens when I'm not even trying.
 

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