Straight pipes on Sporty
#31
03-07-2019, 12:49 PM
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Kevin, your links have some good info on making low restriction exhaust systems run better. I'm happy with the way my 1200 runs now, but just curious, when you put TTIs on a very low restriction exhaust system, does that combination work fine with stock jets on a carbed bike, or does the bump up on the low speed speed jet still make it smoother at lower rpm?
I remember running lollypops in the late 60's, really throttled the power on small displacement Japanese bikes that you needed to wind up to get good acceleration, and the vibration would occasionally pop the retaining pin out and I'd lose them, good thing they were cheap back then. Saw a lot of Honda 305 Scramblers that had the short mufflers on their high pipes cut off and running lollypops.
I remember running lollypops in the late 60's, really throttled the power on small displacement Japanese bikes that you needed to wind up to get good acceleration, and the vibration would occasionally pop the retaining pin out and I'd lose them, good thing they were cheap back then. Saw a lot of Honda 305 Scramblers that had the short mufflers on their high pipes cut off and running lollypops.
Conversely, if the tune/jetting was poor, it will still be poor after installing the TTI's.
This is because the power gain from the TTI's comes from reduction of reversion (without a significant increase in power robbing back-pressure), which results in faster exhaust gas velocity, which results in a better fill and burn.
#32
03-07-2019, 12:51 PM
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At 3" wide open you will get good results from the 158's. You will get better from the 258's, but not nearly the improvement going from 158 to 258 as you will get from nothing to 158.
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#33
03-07-2019, 02:20 PM
If I get the TTI's for his bike to increase torque, (I'll have to measure his pipe diameter), are they installed right near the end of the pipe, or does it make a difference if they are further up in the pipe?
#34
03-07-2019, 03:45 PM
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Jumping in and derailing a thread here, but, on my son's 1200 Sportster he has drag pipes. my 1200 Sportster with SE Slip on's feels like it has more torque down low, which is what I expect.
If I get the TTI's for his bike to increase torque, (I'll have to measure his pipe diameter), are they installed right near the end of the pipe, or does it make a difference if they are further up in the pipe?
If I get the TTI's for his bike to increase torque, (I'll have to measure his pipe diameter), are they installed right near the end of the pipe, or does it make a difference if they are further up in the pipe?
LINK to instructions.
That said, we have Customers that have installed them much further up the pipe than that and still experienced a good bump in low and mid range torque...but they would have seen more by install them within 2" of the end of the pipe.
#35
03-08-2019, 07:16 PM
Straight pipes
Okay . . . Got the 158s today. I installed them and rechecked my muffler diameter. It is closer to 2¾" than to 3". Started it up . . . sounded great. Would'a took it out but we're having near blizzard conditions right now. I'll update you.
#36
03-08-2019, 09:56 PM
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Sounds like you got the right ones then. I believe you're going to enjoy the improvement!
#37
03-10-2019, 05:21 AM
They work best if they are installed no more than 2" from the end of the pipe.
LINK to instructions.
That said, we have Customers that have installed them much further up the pipe than that and still experienced a good bump in low and mid range torque...but they would have seen more by install them within 2" of the end of the pipe.
LINK to instructions.
That said, we have Customers that have installed them much further up the pipe than that and still experienced a good bump in low and mid range torque...but they would have seen more by install them within 2" of the end of the pipe.
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DK Custom (03-10-2019)
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