Build or buy expansion chamber?

Discussion in 'Performance Mods' started by BikeBuilder43, Jul 10, 2016.

  1. BikeBuilder43

    BikeBuilder43 Member

    I always take the baffles out. Some people like low end but i like to feel it pull harder as i go faster. Will the SBP expansion chamber yield a lesser power increase? How does it compare to the MZMIAMIPARTS pipe in terms of performance and where the powerband is in the rev range
     

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  2. jaguar

    jaguar Well-Known Member

    removing the baffles only makes it louder which fools the unexperienced into thinking it has more power
     
  3. Frankfort MB's

    Frankfort MB's Well-Known Member

    From what ive seen it actually does make it faster. Not much though.....
    My engine never did run right at full speed with the baffles
     
  4. BikeBuilder43

    BikeBuilder43 Member

    I have felt the noticable difference in pull without the baffle. I've had bikes that didnt have the power to reach full speed until i removed the baffles. If there was no difference I would leave em in.
     
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  5. jaguar

    jaguar Well-Known Member

    hmm... I wonder if some exhausts are more restrictive than others. I noticed no difference with mine (back in 2010).
    Any way I don't think it's a good idea to make a nuisance of yourself with too much noise when there are tried and true methods of increasing power.
    If you have a stock CDI then dremel it to allow the magneto to be 5 degrees more retarded which benefits top rpm power.
    http://www.dragonfly75.com/motorbike/images/woodruff2.jpg
    Also use sandpaper on glass to plane down a stock head for more compression.
    And make your own gasket from hi temp gasket material which seals much better than aluminum for more engine efficiency due to less loss of combustible mixture past the gasket.
    Also chunk the stock air filter and put one on that is less restrictive.
    Also lessen the hole in the main jet till the spark plug is no longer black. Too rich lessens power.
    (use solder and micro drill bits or buy a few smaller sized main jets)
     
  6. BikeBuilder43

    BikeBuilder43 Member

    Every one i had was had more torque and would reach top speed more quickly. The pull was definitely noticeable. I live in the country so noise isnt an issue. I rolled some teflon tape into a rope and put it in place of the head gasket after sanding down the head. It squished down to almost nothing and makes a great seal. I've been running it like that for a while now with no issues. Had a broken motor mount stud that caused a lot of vibrating and a loss of power. Got it out and replaced it with a bolt. Should help out a lot.
     
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  7. jaguar

    jaguar Well-Known Member

    well maybe the new pipes are more restrictive than they were 6 years ago.
    consider also that you are subjecting your own ears to excessive noise which does slight damage which you won't notice now but you will when you get to be old.
     
  8. BikeBuilder43

    BikeBuilder43 Member

    I won't argue with you on that one. Gonna check out what you said about porting to retard timing.
     
  9. BikeBuilder43

    BikeBuilder43 Member

    Love how the pics make it idiot proof. Lol Seems easy. Wouldnt there be 1mm of play?
     
  10. BikeBuilder43

    BikeBuilder43 Member

    Wait a minute...wouldnt you need to take off 1mm from the left hand side since the crank turns counter clockwise?
     
  11. jaguar

    jaguar Well-Known Member

    since it turns clockwise by making it more CCW causes the spark to happen later (retarded which is better for top end power)

    yes there is 1mm play there but if the fit between magneto and shaft is good then just the tightness from the nut keeps it in place.
    check it this way: remove the woodruff and put the magneto on the shaft and then rotate it without rotating the shaft.
    either on the magneto or the shaft you will see telltale marks where the high spots met. If that happens then they aren't mating well and you need to use valve grinding paste. Put it on the shaft and manually rotate the magneto. that will grind down the high spots.
     
  12. Steve Best

    Steve Best Well-Known Member

    My testing with a GPS speedo on a hill with a 2015 GT5A and 2013 GT2A indicated more power with baffles in.
    My round trip to work is 50 kms. I often do a 50 to 100 kms tour in the evening. Takes an hour or two.
    I'm racking up the miles pretty quick. Still running stock Grubee exhausts so far.
    The chromed exhaust is quieter and faster than the supplied black catalyst exhaust.

    Steve
     
  13. jaguar

    jaguar Well-Known Member

    Interesting. I'll bet bikebuilder did his tests on level ground.
    Probably these engines like more back pressure at mid range RPM and less back pressure at top RPM.
     
  14. BikeBuilder43

    BikeBuilder43 Member

    I thought if you are looking at the shaft from the left side of the bike where the magneto is then it turns counter clockwise( same direction as the wheel)
     
  15. BikeBuilder43

    BikeBuilder43 Member

    Or am I missing something?
     
  16. Frankfort MB's

    Frankfort MB's Well-Known Member

    I have the 2015 epa approved grubee exhaust and it is so stopped up I can't breathe through it lol!

    At low rpm it doesn't have as much power w/o baffle but mids seem to be better.... Top end isn't that noticeable, didn't effect top speed though
     
  17. butre

    butre Well-Known Member

    the mag turns clockwise, the gears in the clutch side reverse the rotation
     
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  18. BikeBuilder43

    BikeBuilder43 Member

    OOOHHH thats true. Good info. Lol
     
  19. jaguar

    jaguar Well-Known Member

    on motorcycles the shaft turns CCW. this engine is opposite because it doesn't have the extra shaft that motorcycles have for the gears.
     
  20. BikeBuilder43

    BikeBuilder43 Member

    Jag i knew you gave good advice. Found the right piece for the dremel and cleaned up the exhaust port and pipe. Got a better match. Dremeled the little woodruff key near the magneto. Man it feels like the faster i go the harder it pulls. I love it! Starts much easier too. Right when i engage the clutch it fires right up. Thank you for the good info.
     
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