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Author Topic: cobra drag 6x6 drag pipes  (Read 1082 times)
rknef777
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Posts: 88


Lake Martin, Al.


« on: March 25, 2014, 08:27:47 PM »

can anyone tell me if you need to make any adjustments, ie jets with these pipes.  looking at a set on eBay for good price
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Bighead
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Madison Alabama


« Reply #1 on: March 25, 2014, 10:12:19 PM »

Some say yes and some say no.
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1997 Bumble Bee
1999 Interstate (sold)
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larue
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Clermont,FL


« Reply #2 on: March 25, 2014, 10:19:18 PM »

installed mine on 3 years ago, didnt do any jetting, bike runs just fine and 20,000 plus miles later  no blueing either  cooldude
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twdurdentwd
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Posts: 232

Sebastian, Florida


« Reply #3 on: March 26, 2014, 06:04:54 AM »

can anyone tell me if you need to make any adjustments, ie jets with these pipes.  looking at a set on eBay for good price

Some are lucky enough to not need to jet the carbs, but I CANNOT stress enough how important spending that extra $80 is..My bike ran fine for about 15k then the blueing of the pipes from running lean. Then hydrolocking one morning on my way to work...which then involves removing the engine and replacing the newly broken rear case around the starter idle gear pinion. I assumed this was just a freak happening until it happened about 3k miles later AGAIN. So Guess what's happening as we speak? Yup...engine's out again and I'm paying another $200 in parts for this repair and a LOT of time which is more valuable to me.


What happens is, after switching exhaust, it changes the back pressure on the system...I'm not sure what makes the difference with the amount of time that passes before the incident happens; but, the carbs will overflow and run into the pistons overnight, then next morning or even a couple hours later upon startup. *CLINK* So now you're pulling out that thin-wall 18mm deep well and pulling the plugs hoping to turn the motor over without hearing any extra music. Then you better make sure you do an oil change because you can bet the oil will be diluted, oh yeah and your plugs will probably be fouled.
Save yourself the trouble and throw a jet kit on it and look up one of the videos on this site about how to adjust them then sync the carbs. Plus a jet kit will help your hp a little bit too so why not.
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00' Valk tourer - 6-6, trigger wheel
00' Valk std - complete build
00' I/S salvaged.. Transplant to std
Chrisj CMA
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Crestview (Panhandle) Florida


« Reply #4 on: March 26, 2014, 06:37:40 AM »

Yes, a thorough evaluation of the fuel mixture to decide about jetting is needed any time exhaust is changed.  BUT, its wrong thinking to link a change in exhaust "back-pressure" to a hydrolock.

I have a '97 Valkyrie that had cobra 6x6 exhausts put on at 5K miles.  No rejetting...12 years later and 135K miles down the road and shes still running perfect and never a hydrolock
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olddog1946
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Moses Lake, Wa


« Reply #5 on: March 26, 2014, 07:36:05 AM »

Your bike will run a tad leaner with the Cobra's but not really necessary to change jets. Besides that when you take them back off to put the stock pipes back on you'll be glad you didn't mess with them.
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twdurdentwd
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Sebastian, Florida


« Reply #6 on: March 26, 2014, 08:10:34 AM »

Yes, a thorough evaluation of the fuel mixture to decide about jetting is needed any time exhaust is changed.  BUT, its wrong thinking to link a change in exhaust "back-pressure" to a hydrolock.

I have a '97 Valkyrie that had cobra 6x6 exhausts put on at 5K miles.  No rejetting...12 years later and 135K miles down the road and shes still running perfect and never a hydrolock

That's fair. If you get the chance however, take a set off one side and using a flashlight, look up at the valves and guaranteed they're white
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00' Valk tourer - 6-6, trigger wheel
00' Valk std - complete build
00' I/S salvaged.. Transplant to std
rknef777
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Posts: 88


Lake Martin, Al.


« Reply #7 on: March 26, 2014, 03:15:27 PM »

thanks for the great reply's.   still undecided on the cobra pipes and the rejecting but some good info.  seems like about 50/50 on all the stuff I read wether or not you need to rejet.
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twdurdentwd
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Sebastian, Florida


« Reply #8 on: March 26, 2014, 06:52:22 PM »

Jetting does two things:  removes the unknown possibilities, and makes bike perform better... Why not?
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00' Valk tourer - 6-6, trigger wheel
00' Valk std - complete build
00' I/S salvaged.. Transplant to std
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