If a person installs after-market cobra exhaust pipes on his bike does the bike have to be re-jetted? I have a 750 Kawasaki Vulcan I'm considering changing exhausts.
2007-03-12 08:31:56 · 11 answers · asked by Don S 1 in Cars & Transportation ➔ Motorcycles
Most aftermarket exhaust manufacturer's will either include richer jets with your pipes or recommend the correct size for your application.
Adding a less-restrictive exhaust system can alter the air/fuel ratio by changing the volumetric efficiency of the engine. In other words, your engine will run leaner causing higher engine temperatures, pipe bluing and exhaust popping on deceleration. If you also change air filters to a K&N or Uni-filter, it may be even worse. The solution is to re-jet.
Jets are cheap, relatively easy to replace and experiment with and I think you'll be very happy with the results once you do it right.
If your pipe manufacturer doesn't have a recommendation, then try a 10% increase in jjet size at first. For example if your bike has a 115 main jet and 40 pilot jet, try a 127 main and a 44 pilot. For absolute best results you can find a shop with a dyno to try different jet sizes with or visit other Vulcan owners on a public forum, such as on http://forums.delphiforums.com/kawvulcan .
Good luck!!
2007-03-12 09:57:40 · answer #1 · answered by Anonymous · 1⤊ 0⤋
drop a new set of plugs in first. if all u did was switch the pipes, run the bike for about 25-40 miles, and see how the plugs look. if they're ash grey, ur a bit lean, but passible. if paper white, its too lean and u can damage the engine.
if it starts poppin on decel, u more than likely need a slight adjustment in the mix, same if it hesitates grabbin a big handful of gas. if the bike behaves fine, then u most likely dont need a re-jet....but if u change the air filter, u most definately will.
2007-03-12 09:47:58 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Yes. If the bike is carburated look on the factorypro site and see if they have a jet kit made for a full exhaust. I don't know what year yours is. Read a bit over there and you will see that you need to re-jet.
2007-03-12 09:15:38 · answer #3 · answered by Anonymous · 2⤊ 0⤋
I changed exhaust( added headers) and put on K&N air filter on my 850 suzuki, stock jets were a 17, I had to go all the way to 64
2007-03-16 07:10:48 · answer #4 · answered by franksr57 2 · 0⤊ 0⤋
Yes
Adding performance exhaust pipes changes the air-fuel mix and if you do not rejet, the bike will tend to run lean.
http://www.motorcyclegiftshop.com/motorcycle_jettingkits.html
2007-03-12 09:28:22 · answer #5 · answered by lepninja 5 · 2⤊ 0⤋
If after market pipes are installed, it's not absolutely critical to re-jet. Re-jetting will enhance the performance that can be gained from installing those pipes.
2007-03-12 09:30:11 · answer #6 · answered by guardrailjim 7 · 0⤊ 2⤋
in the beginning examine with the broker approximately voiding your guarantee. changing the exhaust generally in straight forward terms makes the motorcycle noisy and infrequently provides from now on capacity from the motor and so no further stresses on it. there's no ideal time or mileage to in good condition different factors offering you do no longer void the guaranty. oftentimes the 1st element replaced is the tires for a extra effective high quality kind.....
2016-10-18 05:09:55 · answer #7 · answered by ? 4 · 0⤊ 0⤋
I doubt it needing to be rejetted. You have changed anything in the engine like boring and making the engine displacement. The motor still will only rev out so far. the new pipe will really just make the bike obnoxiously loud. You will think it is faster because the noise will destroy your brain's ability to reason.
2007-03-12 08:42:29 · answer #8 · answered by david d 5 · 1⤊ 3⤋
yes you need to re jet, plus re sync the injector ports
2007-03-12 16:13:53 · answer #9 · answered by mrmiketattoo 3 · 0⤊ 0⤋
Son took the muffler apart removing the inner baffles?
then put the muffler back together so it looks original
2007-03-12 08:39:38 · answer #10 · answered by Mopar Muscle Gal 7 · 0⤊ 4⤋