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New Slip On Exhaust and Economy

Discussion in 'Technical and Troubleshooting Torque' started by joetdm, Mar 31, 2010.

  1. Is it normal to get better economy after fitting a new slip on exhaust?
    I've fitted a new Megacycle slip on to my Suzuki GS500F

    With the stock exhaust, I'd fill up at 350K and I'd usually put in between 14.5 and 15 liters. That's around 4.4 liters per 100K.

    I seem to be using less fuel now.
    Just got back from the servo and at 300K I only put in 11.4 liters which is less than 4 liters per 100K (calculates to 3.83 L per 100K).
    A difference of around 0.5 liters per 100K.
    My previous fill was at Daylesford on the Choc mill ride last Saturday so most of it was hwy riding. I've noticed it on the last few fills.

    Is this normal?

    For those interested, I replaced it as I thought stock was too quiet and preferred to be heard a little better in traffic and not for better performance which I think is the same.
    But the economy side of it is a bonus....

    And yes I fill it to the same level every time.
  2. Likely running lean as a result as the extra airflow from the new exhaust.
  3. I've recently put a slipon and my fuel economy has gone down the drain.

    I normally get 240km outta my gsxr before my fuel light turns on. Now I get around 210km.
    May have something to do with me revving it heaps and riding in the lower gears to hear it thought ahaha
  4. I think this would be right. The bike is probably running lean, which would obviously mean less fuel usage. But, if it is running to lean it will cause damage to your engine. Quite often you need to rejet the carby when changing the exhaust system. From what I have read, the GS500 is setup to run slightly lean from the factory, so if it is more lean now it might not be a good thing.
  5. Half a litre less on four litres is a fair percentage ( about 12%).

    Might be a good idea to get it tuned, running lean is not a good thing.

  6. Same thing was with my dads dirt bike, (TTR250). Wacked a pipe on it and just as i researched before hand it was running lean. A good indicator is that it will be "popping" on deacceleration. Regardless you should tune/jet your bike if you make modifacations to the airflow/fuel setup. You will find it will run better once it is sorted out to.

    Im surprised you havn't reported a loss in power as well seeing as it will be running more lean. There are lots of stickies on dirt bike forums about jetting a 4 joke if you wanna try yourself ;) Just do a bit of a google and you fill find them no worries.

    Though your best starting point would be to find someone who has put on a similar pipe on the same bike and go off there jetting for a baseline. Depending on there standard humidity/altitude levels anyway.