Questions for the tuning experts.

[Redline +]

Purchased my first Valk 9 months ago, 2002 with 5000 miles. Original owner had his local Honda shop install Cobra pipes and said they rejetted. First thing I did was dyno the bike and check A/F ratio. It was right on, the Valk runs like a scalded dog, no performance issues, good top end power. Tested to 137 indicated fully loaded with Hondaline windshield, she had a bit more but I didn't. I've not been on or raced another Valk so no baseline, my guess is this is just an average Valkyrie.

The problem...9 months and 10,000 miles later I've noticed about three days out those Cobra pipes get kinda loud and every consecutive day they seem louder. They are baffled and I'm wearing ear plugs. I found and purchased some new, unmolested, take-off IS pipes from a local Honda dealer and have been contemplating.

The questions...if I install the stock pipes, is it automatically going to be to rich? Would it be a waste of time and money to dyno with no jet change? Should I jet back to stock specs before dyno check? What kind of performance loss/gain can I expect switching from a properly jetted cobra exhaust to a properly jetted stock exhaust? I have no knowledge of any timing mods.

TIA

Redline  

[Warlock]

Most time when they install the Cobra pipes they change out the needles. By doing this it will get them back to almost stock hp. When installing the Cobra pipes and leaving the stock needles you lose around 8 to 10 hp but no mpg lost. When you install the needles you get the hp back, but lose mpg. If they installed the aftermarket needles they will be able to adjust them. Moving the clip up will make them more lean and moving the clip down will make them rich. It want hurt running the stock pipes with these needles. So you might have to adjust the clips. I would run and see how it acts. Also just remember when changing out the pipes make sure to remove the old gasket. A flat head screwdriver works good for this. When tightening the headers bolts up be careful they will twist off real easy. Only torque to 7 foot lbs. Once you have them torqued after riding it for around a hr or so let it cool down and re-torque again. After about a month recheck again. This should be the last time to check them.
David

[Ricky-D]

Since the pipes you are running are baffled there ought not be a big difference buy installing the stock pipes back on.

I likewise would suggest to do nothing extra to accompany the changing of the pipes.

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