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Discussion Starter · #1 ·
I need to know if I will need to rejet if I replace the OEM air filter to a K&N. I am running the stock pipes and stock set-up.
Any input would be appreciated.
Thanks.
Cheers!
 

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probably
 

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I have a customer with same set up as you. He installed a new KN about a week before he brought the bike for tune-up and service. The bike was running very good and plugs looked perfect. Neither he or I touched the jetting :wink: I would say try it and go from there
 

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I swapped out the stock filter with a K&N in the stock air box and didn't need to rejet.
 

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If you can get by without doing a jet change you are better off. Jet kits lower your mpg big time. Mine droped from 48 mpg to 38 mpgh riding like a human should. I then droped a 1800 rear final into place. The bike was unreal for a 1300 but my mpg droped again big time this time down to 32 mpg. I will say this 60 to 80 mph under 4 seconds. My top speed was not hurt because the lower gear allowed the engine to pull easier. 118 mph top end.
All speeds was done with a gps so these speeds were close to being right on.
 

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KDKing said:
I need to know if I will need to rejet if I replace the OEM air filter to a K&N. I am running the stock pipes and stock set-up.
Any input would be appreciated.
Thanks.
Cheers!
"Rejet"? NO.. you will NOT have to change jet sizes.

Adjust A/F screw? Maybe.. depends on how it is currently set.. any change would be fractional tho.
 

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It's a matter of how much flow you have as a whole with the engine.

Changing the pipes and leaving the intake alone - rejet isn't likely to be needed
Changing the intake but not the pipes - rejet isn't likely to be needed

Changing pipes and intake, best having it checked on a dyno that does exhaust gas analysis. From there, adjust as needed.
 

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Discussion Starter · #9 ·
Thanks for the quick response. I knew I could count on some good solid feedback from the folks on this board.
Cheers!



www.canadianxriders.com
 

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You probably don't have to, but I did. I put on the Dynojet stage II kit after intalling the K&N filter. I had a noticable difference in pickup and acceleration and no decrease in fuel mileage. Much better start up and nearly no warm up time.
 

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I asked the service guys at my dealer this exact question.

He said you can usually get away with changing the pipes OR changing the air filter without re-jetting.... but not both.
 
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poolmaster79 said:
You probably don't have to, but I did. I put on the Dynojet stage II kit after intalling the K&N filter. I had a noticable difference in pickup and acceleration and no decrease in fuel mileage. Much better start up and nearly no warm up time.
Does re-jetting usually involve replacing the jet kit or can the stock be adjusted accordingly?

The reason I ask is I bought my bike used and the previous owner had changed out the pipes and went with the pro series hyper charger. According to him the local stealer adjusted and said they are within spec. ALL my friends I ride with have told me im running rich. (they see and smell it) I called a local mechanic and the first thing he wanted to do (without seeing the bike) was get a new kit ordered up. I'm bringing it in tomorrow and if I dont need the new one, it would be nice to know. I suppose I should find out if it was even replaced the first time around..
 
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