Author Topic: Exhaust Mods in Production Bike Class  (Read 3056 times)

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Offline MiltonP

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Exhaust Mods in Production Bike Class
« on: April 17, 2009, 04:39:38 PM »
It is my understanding that it is legal to modify the exhaust system as long as it retains the stock appearance and rear outlet look/design.  If that is true, do most of you running production bother with it?  I plan to eventually run the bike in modified as well and so far most forums indicate none of the aftermarket 2>1 or 2>2 full systems or slip ons perform better than the stock 2>2 exhaust.  Of course they are guaging performance by street and track days not running full out in a standing mile so I am thinking there may be better choices.  If not, I would like to modify the stock exhaust the right way if there is such a thing!   :-)

The bike is a 2009 Ninja EX500 so I am assuming there is emmissions stuff inside there as well.  The bike is not destined to return to the street in the forseeable future so I have no issue with changing that.  For that matter, I should probably be looking to eliminate the emissions stuff on the intake side as well.

Offline Cajun Kid

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Re: Exhaust Mods in Production Bike Class
« Reply #1 on: April 17, 2009, 06:29:18 PM »
Milt,
 
I am not a current bike racer, but have many years doing it in the 70's, 80's and early 90's...

That bike as I recall is "stopped up" on the exhaust,,, some things that retain the stock appearance, that may help. would be to "if possible"  remove the baffels in each pipe, if not doable,,, punch 6 to 8  1/4" holes in the end caps, and baffle plates,,,, then do the appropriote air filter, air box, carb and jet work...

Please consult with the the current bike on this forum tuners first,, as they may certainly be more up on current tuning...and rules....
My option is old school low buck tuning fix,,,, It does work,,, but I am old and behind the times on this stuff now,,

Charles
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Offline MiltonP

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Re: Exhaust Mods in Production Bike Class - Jet Kit Brands/Quality ?
« Reply #2 on: April 17, 2009, 07:00:25 PM »
pretty sure drilling holes in the endcap would be illegal in production class.  Not sure how tough it is to cleam it up/out properly with just removing the endcap as it looks like a serious pain to open it up further to do the work.  I may turn them over to Speedwerks in Dover to do the job.  Looks like I better get a jet kit for them to use to tune it afterwards as well.  They lean towards using Dynajet but I was leaning towards Factory Pro.  Anyone have thoughts on which may be better?

Couldn't resist firing it up briefly with no cans on it.   Almost sounded like a real motorcycle for a moment!   :cheers:

Offline fredvance

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Re: Exhaust Mods in Production Bike Class
« Reply #3 on: April 17, 2009, 07:33:27 PM »
Milton, as you said the exhaust has to look completely stock, the exit orfice( I love that word, sounds nasty) has to be the same size as stock, anything that doesn't show goes. So you can remove everything from the inside of muffins,mid pipes, etc. If you free up the exhaust flow and do nothing to re tune then it is kind of an exerxise in futility. You will need a way to adjust your a/f mixture, like a power commander. of course I am assuming that your bike is fuel injected with an ecu.
Well I got side tracked and there are a couple of posts since I started this. Drilling the end caps is definitely not allowed in production.
Fred
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Offline MiltonP

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Re: Exhaust Mods in Production Bike Class
« Reply #4 on: April 17, 2009, 08:01:46 PM »
Never assume....  EX500 is not fuel injected so tuning will have to be the old fashioned way.  Not too many 'big' shops are showing much interest in working with carbs these days so I may have to learn to tune this myself though Speedwerks in Dover showed some interest.  I will probably go with a Dynojet jet kit since they are used to working with that brand.  I do have a dragstrip within 45 miles if I want to take on the challenge of seat of the pants tuning though I am not sure if the 1/4 mile is enough to really guage for a mile run.  Not sure if Rachael and Shane get on the forum but they are nearby so maybe they have tuner options though I am pretty sure they were running FI bikes so...

Offline MiltonP

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Re: Exhaust Mods in Production Bike Class - Tamper Resistant Cans
« Reply #5 on: April 18, 2009, 11:33:06 AM »
Thes cans are built like tanks.  Took it over to DucPond which has a lot of experience prepping race bikes and had the man look at it.  Getting the nedcap off would likely be nothing more than grinding a few rivets but the chrome/aluminum 'sleeve' has at least nine welds that appear to tabs that are part of the inner chassis.  It would be very difficult, i.e... expensive, to do a proper job and keep the stock appearance.  I reckun I will run as is for production and look at a different exhaust for when I go modified.  I can't picture getting good results via drilling and whatever is on the other side of those welded tabs will likely stop 'stuff' from being able to slide out.  I will ask if anyone of the ninja forum has opened one up just in case but not hopeful.

Offline mtkawboy

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Re: Exhaust Mods in Production Bike Class
« Reply #6 on: April 18, 2009, 02:06:59 PM »
Does it have Cv carbs or conventional carbs on it ? For top speed running youre mostly just looking at the main jets. Id see if any larger sizes are available for them. Newer bikes are lean on the pilot and needles and rich on the main and you will be running at altitude so it may not take as much work as you think it will. Putting it on a dyno or running it is the only way to tell.

Offline fredvance

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Re: Exhaust Mods in Production Bike Class
« Reply #7 on: April 18, 2009, 03:52:54 PM »
If you are talking about Shane San Miguel he is on here sometimes, currently he has 2 busa's he is running, fuel injected.
WORLDS FASTEST PRODUCTION MOTORCYCLE 213.470
Vance&Forstall Racing
WOS 2011 235+MPH
Engine by Knecum, Tuned by Johnny Cheese.
Sponsers Catalyst Composites, Johnny Cheese Perf, Knecum Racing Engines, Murray Headers, Carpenter Racing