Gutting Cobras?

[Jayo76]

Anyone ever gut Cobra dual slash cuts?

Im bidding on ebay for a set, but am aware of the decrease in HP they impose. Just wondering if I gutted them and rejetted would i gain power as well as making them noiser, which would also be desirable in my case!

Any thoughts?

 

[SpecOps13]

I think there was a thread about this not long ago. No extra HP because of restrictive stock headers and collector box. That's what I remember. Nothing will gain HP that slips on.

Welcome to VMF Anyway....:biglaugh:

Oh, they would be noisier.

 

[forestry62]

Does anybody have a sound clip of a Gutted Cobra slashcut 4 into 4 that can be compare to the sound clip of a ufo Quadzilla. They look somewhat similar on a v- max
but how do they compare in sound???? Post on you tube if you can......Thanks!

 

[SpecOps13]

I listened to the Quadzilla's, they actually sound pretty good. Do they actually mount to the stock header like the Cobras??? I'm not so sure. I ran my bike with an open exhaust system today as I'm putting Marks 4-2 Exhaust on tomorrow. I wasn't very impressed, it sounded like the Figure 8 Races.

forestry62: Welcome to the VMF, It's Great.....

 

[vmax2extreme]

Anyone ever gut Cobra dual slash cuts?

Im bidding on ebay for a set, but am aware of the decrease in HP they impose. Just wondering if I gutted them and rejetted would i gain power as well as making them noiser, which would also be desirable in my case!

Any thoughts?

I had the cobras on a 95 vmax I purchased way back. Dyno'd it and it actually lost HP with that setup. Changed up to the supertrapps and gained plenty to my satisfaction.

 

[tugla]

what was the dyno numbers with the cobra's on???

 

[vmax2extreme]

what was the dyno numbers with the cobra's on???

With the cobra 4into4 slip-ons, my dyno showed me at 98rwhp. Thats just pathetic! I pulled them off quickly to use supertraps and was pulling near 120rwhp then.

At thunder this past year, I was riding with a guy that had a 94 with those cobras. We went on a ride and at around 80 miles, he was sputtering for gas. I was like so shocked since I know my 05 with trapps can get around 120+ miles on my tank easily. When I asked him about the setup, he wasnt sure since he had a bike shop do it for him. I told him he's running far too rich to be out of gas already!

 

[tugla]

With the cobra 4into4 slip-ons, my dyno showed me at 98rwhp. Thats just pathetic! I pulled them off quickly to use supertraps and was pulling near 120rwhp then.

At thunder this past year, I was riding with a guy that had a 94 with those cobras. We went on a ride and at around 80 miles, he was sputtering for gas. I was like so shocked since I know my 05 with trapps can get around 120+ miles on my tank easily. When I asked him about the setup, he wasnt sure since he had a bike shop do it for him. I told him he's running far too rich to be out of gas already!

must have been set up rich, mine gets a constant 100-105 miles before the light turns on. this past summer i got a few times 43mpg out of it. all stock carbs wit the cobra's. i know its down on power but looks and sounds sweet. might mod mine out to help bring back some power to stock levels

 

[vmax2extreme]

must have been set up rich, mine gets a constant 100-105 miles before the light turns on. this past summer i got a few times 43mpg out of it. all stock carbs wit the cobra's. i know its down on power but looks and sounds sweet. might mod mine out to help bring back some power to stock levels

Oh I know he was running far too rich. I smelled him doing down the road...not good! Yeah, your getting about what they should get. I believe mine was getting about 110 before the light. They do look good and sound great, its just the lack of HP gain due to less back pressure on the exhaust system. I run SS Supertrapps with open endcaps. Mean and LOUD!

 

[mavgrab302]

You cant gut them, what you can do though is drill out the mid plate to about 1inch if you have a long drill bit, I used a 1 1/2 slim extension with 3/8 bit then grinded it using the extension. The small glass pack looking holes are made to the pipes themselves, and weren't removable.
I have a video I found lastnight after posting my marks that I'll place later today. Alot louder at idle but tappers off at cruise. wasn't loud enough for me, so I sold them to someone on craigslist.. even with them drilled out the performance still sucked, Marks exhaust made a world of difference, watchg out for spinning rear wheel..lol

 

[4gasem]

I've seen two bikes with Cobras, and both had around 95bhp. That's a HUGE loss in power...

 

[vmax2extreme]

I've seen two bikes with Cobras, and both had around 95bhp. That's a HUGE loss in power...

Wow! Thats worst than what mine dyno'd in at. I was at 98rwhp when I tested them out. Got rid of them quick for supertrapps. Like night and day for sure. Those mark pipes are nice pipes. I wish my pockets went that deep!

Enjoy and ride safe!

 

[SpecOps13]

Marks Exhaust: I waited for Mark to have a sale and made my pockets run that deep. Best choice I've made in a long time....... Tremendous midrange increase....:biglaugh:

 

[mavgrab302]

He are the drilled out cobras I had a while back before the marks. There drilled because they can't be gutted. I tried and couldn't because of the bends or the welds to the outside made it difficult to impossible.

video will be processed by youtube then can be watched.
http://www.youtube.com/watch?v=O1nkT7yc1Nc

 

[vbmike]

What would it do for performance and sound if you were to drill 6-8 holes in the end caps around the outlet? I would assume this would improve flow/power and make the bike a bit louder as well. Anyone try this? Check out the video and you can see the holes I'm talking about. This bike sounds mean.

http://www.youtube.com/watch?v=pvbgFIWNiHQ

 

[one2dmax]

They sound like shit in person and will NEVER perform worth a shit. About the only thing I like about them is they look cool. Had my first set probably 20 years ago and didn't realize what I was missing for power.

I've learned a bit since then.

Sean

 

[vbmike]

I realize they are not a performance pipe, this thread is about trying to improve the performance. Personally I think the pipes sound and look great, just need more power.

Has anyone tried drilling the end caps out?

 

[one2dmax]

Drilling the end caps will not improve the power. The problem is the loss in the scavenging due to each cylinder having it's own pipe. This is what is hurting the power.

Sean

 

[vmax2extreme]

Marks Exhaust: I waited for Mark to have a sale and made my pockets run that deep. Best choice I've made in a long time....... Tremendous midrange increase....:biglaugh:

What, Marks exhaust has sales?

 

[4gasem]

Not very often!


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