07 Sporty & Rush 1.75 slipons

Discussion in 'Sportster Models' started by Semmessporty, Mar 12, 2008.

  1. Semmessporty

    Semmessporty Member

    I live in Mobile, Al. The service dept at Mobile Bay Harley advised me today that I could put on 1.75 Rush slipons and do nothing else to my 07 Sporty and it will not run lean. They said they have put them on a new Sporty and checked and it is safe to run them with no fuel pack or anything else as long as I don't change the air cleaner from stock. They said the 1.75's are the same baffling that is in the stock mufflers. The way the Rush are designed they are just louder. Any Teck's out there that agrees with the service dept and service manager here in Mobile?
  2. captnc12unch

    captnc12unch Member

    Why spend the money if your not gonna get any performance? You could hollow out your baffles for way cheaper and about the same results. I had the rush on mine but they were bigger and i also had the fuel pack and se1 air cleaner. I regret buying my tips because i ended up spending the same amount again and bought some shortshots on ebay for 250.00
  3. glider

    glider Veteran Member

    That's a pretty broad statement for them to make. The stock bike is running lean from the factory and any fuel enhancement would make it run better and cooler too. Stock lean settings (EPA) and relieving some back pressure will take it to the lean side of lean. More noise usually means less back pressure which means a leaner mixture.
  4. scottaudio

    scottaudio Member

    As noted, more noise and more open (like drag) pipes means less back pressure (but higher RPM on the top end). However, without replacement of the air cleaner, you do not increase "flow" through the engine, hence no performance increase.

    Performance (meaning HP, torque) are affected by your exhaust in several regards. The reason behind tuned header pipes is that the lengths and diameter are calculated to your engine needs, and believe it or not, the audio noise created from the engine is actually utlized to create a sound wave that helps prevent raw fuel from exiting the chamber. More fuel in combustion chamber equals more power!

    The length of the total exhaust system will affect torque and top end RPM. There are math formulas that help determine all these factors, as both length and diameter are involved as well.

    I have the SE II tips on my bike, with an SE air cleaner and the carb re-jetted to ensure I am not running lean. Lean means holes in pistons, and that is NOT a good thing!

    You can put the tips on, but the lean condition may get you. If the dealer does it, and will still honor your warranty (in writing!), then you can take the chance, with knowledge you may end up with a top end job at some point depending upon circumstances. This is a worst-case scenario.

    Good luck!

    Steve Scott