Cobra 4225 Slip-Ons for Classic/Classic LT - Kawasaki Vulcan Forum : Vulcan Forums
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post #1 of 5 (permalink) Old 06-19-2012, 10:26 AM Thread Starter
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Cobra 4225 Slip-Ons for Classic/Classic LT

Your comments on the Cobra Model 4225 Slip-Ons for the 1700 Classic/Classic LT would be appreciated:

1) Any added decel popping? (Without Fuel Manager and no Intake Mods)

2) Performance vs. Stock?

3) Sound vs. Stock?

4) Weight reduction over stock?

5) Any reduction in radiant exhaust heat over stock? (I have the Kawi Heat Shield Kit Installed)

Thanks in advance!
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post #2 of 5 (permalink) Old 06-19-2012, 10:53 AM
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I put the Cobra 4225's on my 2009 LT.

1. I don't know that they added decel popping, they just made it easier to hear.
I added a Cobra 2000 fuel processor that that helped with the decel popping but didn't eliminate it by any means.

2. I didn't really notice any performance increase but really wasn't expecting any.

3.Loved the sound. Not loud while cruising but come alive under acceleration.

4.Weight reduction was minimal if any at all.

5. I noticed no difference in heat.

I figured all i would get out of the Cobras was better sound & i did, which was worth it to me. If your expecting anything more you may be disappointed.
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post #3 of 5 (permalink) Old 06-19-2012, 11:28 AM
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I'm the sole forum user who will post on this with some experience. I have recently been dealing with excessive decel popping and random lower RPM/speed/off idle hesitation. The issue started with the Cobra PowerPro processor which I have now learned that Cobra has released a modified version of this with some ability to adjust! I tried 2 of these units with a K&N in the stock box and the slip-ons listed. Cobra was great to work with and actually sent me a 3 pot Fi2000 free for my troubles with the first 2 autotune units. I have since adjusted the 3 pot processor every way imaginable without satisfaction. What I can say is aside from the popping and hesitation, the bike does run better out on the slab than it did stock. Here are my most recent efforts with trying to eliminate the popping and hesitation;

This weekend I removed the heatshields with the mufflers installed and noticed right away that the lower muffler did not slip over the pipe all the way to the muffler slip. There was about a quarter inch gap over where the muffler should have been snug and stopped. I installed these last year in the fall and began to question my work. The top muffler was fine. I also noticed a minor amount of soot around the gap where the lower muffler. With the shields removed I fired up a cigar and started the bike. I blew smoke around the mufflers and where the header pipes attach to the heads. Nothing obvious. I took a lighter and watched the flame. Nothing unusual. I then uninstalled the mufflers and checked my work. I quickly realized why the lower muffler was off by a quarter inch. The muffler mounts to a bracket on the bike. This bracket is connected to the frame and cannot be adjusted. When lining up the lower muffler it's clear that Cobra's quality control on this was just not up to par. I reassembled and tightened the clamps down. (Probably too tight.) I also checked the bolts on the pipes at the headers and they were very loose! I torqued them down to about 15 ft/lbs (book calls for 12 but my 3/8 torque wrench is the old school scale type so I did the good enough close enough error on the side of tighter method!) Put everything together and went for a ride. No change!

Here is my last effort;

I have in the garage new o-rings for the tb assembly and seals for the intake manifold. I am going to replace the o-rings and seals and add some Yamabond gasket sealer similar to what Ray did to see if there is any improvement. I did check for leaks at the intake using liquid and spraying it at these points and nothing obvious came up. I'm not convinced a minor leak is not there someplace. So tearing this apart and trying some sealer torquing back to spec may help. I will also be plugging the fresh air hose on the right side during this time. I realize that some popping will be present over the stock cans because they simply will not muffle as well due to the construction and components. The hesitation needs to come out though. Here's the answers to the about questions;

1. see above

2. I may pick up a couple of HP but nothing significant. You'll pick more performance up with an air kit and more fuel into the bike.

3. Sound is much better. Is not obnoxious. When grabbing throttle is were the biggest difference in the two are.

4. Not enough to make a big difference.

5. I wear jeans with draggin liners and pads underneath. I can rest my leg against the pipe and not feel anything for a while. I've noticed no difference in heat over stock.

I will say this, with the heat shields off the stock pipes look like cheap garbage. I have rust marks on mine and discoloration by the headers and where the clamps for the shields are next to the pipes.

If I knew this bike would run hesitation I would do the following mods for sure,

1. Thunder Forced Air Kit
2. PCV with Autotune and custom map.
3. 2 into 1 exhaust (which no one makes) so my second choice V&H Bigshots.

I'm not taking a chance until I get this thing running. I've had the fuel box off and the air filter out and the thing was still popping and hesitating. Checked plugs 100,000 times. If the air intake seal replacement doesn't work, I'm out of ideas.
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post #4 of 5 (permalink) Old 06-19-2012, 02:49 PM Thread Starter
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Thanks to both 11Nomad and 1700Classic for your responses!

Considering how small the Classic/Classic LT Owners Group is, I very much appreciate your detailed answers to Every One of my specific questions!

Next time I have a question about my Classic LT I may just PM both of you

And, if anyone else is interested in the Cobra 4225 Slip-Ons for the Classic/Classic LT, here is a very interesting, time-limited eBay listing:
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post #5 of 5 (permalink) Old 06-19-2012, 03:00 PM
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No problem. I may switch out my exhaust if I get my bike running to my satisfaction. If I do at this point the V&H Bigshots full exhaust is at the top of the list. They look similar to stock yet are a change, they have a decent tone, and I've owned V&H in the past. I've heard Cobra's offerings and they are just too loud for me. Plus factor in the luck I've had with Cobra on this bike it's time to give someone else a shot. Although I will say Cobra's support is top notch. They went out of their way to help me out so in fairness my experience is probably not typical. I would be concerned as to how the Cobra mufflers fit over the pipes though. I've had an issue and there are threads on here about Voyager/Nomad owners having problems with slip on fitment and having to bend the muffler! I will post a pic of the muffler fitment later...
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