Are straight pipes bad??? - TwoWheelForum: Motorcycle and Sportbike forums
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post #1 of 23 (permalink) Old 10-14-2007, 05:39 PM Thread Starter
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Are straight pipes bad???

Yesterday I had nothing better to do so I unbolted the exhaust on my Triumph Daytona and WOW, I really liked how it sounded.

My question is: if I leave the muffler off and just run the straight pipe, is the lack of back-pressure bad for my engine???

Thanks guys
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post #2 of 23 (permalink) Old 10-14-2007, 06:36 PM
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Gay and bad for the motor... you can F up your exhaust valves...

Oh and....

You have probably lost a good amount of power as well.




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post #3 of 23 (permalink) Old 10-14-2007, 06:36 PM
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Oh... and




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post #4 of 23 (permalink) Old 10-14-2007, 06:38 PM
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Problems I see

1. legal - not so much

2. If all you did is unbolt it and the remaining pipe is too short there is a potential to introduce cold air when you rap it up. Causing a sucked, bent, broken, or cracked valve.

3. By losing back pressure you COULD loose torque, and COULD gain high end HP. But most likely the first.

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post #5 of 23 (permalink) Old 10-14-2007, 06:39 PM
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Oh and welcome also

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post #6 of 23 (permalink) Old 10-14-2007, 06:46 PM
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straight pipes arent that good for a bike, because when you let off the throttle, the sudden lack of hot gases being pushed out can cause cold air to be sucked in, which can damage your exhaust valves, and make for a VERY pricey repair.

police will DEFINATELY like to follow and stop you often too.

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post #7 of 23 (permalink) Old 10-14-2007, 07:07 PM
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Just a question,is it ok when it's a big V-twin because of the slower rpm and the lack of valve overlap?

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post #8 of 23 (permalink) Old 10-14-2007, 07:12 PM
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Same problem. The guys that build custom streight pipes for those use a smaller diameter pipe that are long enough to avoid sucking cold air.

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post #9 of 23 (permalink) Old 10-14-2007, 07:24 PM Thread Starter
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Thanks guys - I appreciate the responses. It sounds like the risks are more than it's really worth so i'll just leave the pipe on. It's got a Triumph Race muffler on it which is basically straight through...only a few baffles around the outside of the pipe, but i guess it's enough to makes a difference.

Thanks again!
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post #10 of 23 (permalink) Old 10-14-2007, 08:20 PM
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oh and
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post #11 of 23 (permalink) Old 10-14-2007, 08:23 PM
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They are best on 2-strokes.

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post #12 of 23 (permalink) Old 10-14-2007, 08:26 PM
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Quote:
Originally Posted by kbubp View Post
They are best on 2-strokes.
straight pipes screw up two strokes too. two strokes NEED back pressure to run well. I've never run a two stroke anything and had good experiences with straight piping it.

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post #13 of 23 (permalink) Old 10-14-2007, 08:41 PM
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Quote:
Originally Posted by King Bob View Post
straight pipes screw up two strokes too. two strokes NEED back pressure to run well. I've never run a two stroke anything and had good experiences with straight piping it.
I know dude, I was just being a sarcastic *******.

You will learn in time

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post #14 of 23 (permalink) Old 10-14-2007, 11:40 PM
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i agree and disagree with the opinions in this thread. if you just take off your muff, then yea it could be harmful to your bike. however if its a actual open pipe full exhaust, then i dont forsee a problem. ive had a 4 into 1 open pipe on my bike for years, no problems whatsoever, and ive been in the engine to verify that. ive pulled up next to cops numerous times and if anything they just roll their window up. it will change your a/f mixture so you will have to tune for it. you lose some low end power, gain some high end. whether or not you notice it depends how you ride.

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post #15 of 23 (permalink) Old 10-15-2007, 12:25 AM
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I understand dynce... even my chop is basically an open pipe setup. But you can create backpressure with pipe diameter changes and bends. However, I don't see that being the case with most rocket exhausts.




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post #16 of 23 (permalink) Old 10-15-2007, 12:29 AM
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Quote:
Originally Posted by Gas Man View Post
I understand dynce... even my chop is basically an open pipe setup. But you can create backpressure with pipe diameter changes and bends. However, I don't see that being the case with most rocket exhausts.
true, gotta go whole new setup pretty much, cant just drop the muff.

brocks performance and muzzy's makes some good open pipe setups for sportbikes tho-and they do come with baffles so "wide open" is an option in case you wana creep out at nite, or its just too loud for ya

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post #17 of 23 (permalink) Old 10-15-2007, 01:11 AM
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i have a slight loss of hearing from not wearing ear plugs during my loud pipe years... a straight pipe will be more damaging.

-a|ex
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post #18 of 23 (permalink) Old 10-15-2007, 05:20 AM
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Quote:
Originally Posted by Back _Marker View Post
i have a slight loss of hearing from not wearing ear plugs during my loud pipe years... a straight pipe will be more damaging.

-a|ex
now this is a VERY good argument. quieter bikes do less damage to hearing than a loud pipe will. I even notice a difference on a stock bike vs aftermarket muffler, let alone straight pipes.

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post #19 of 23 (permalink) Old 10-15-2007, 12:23 PM
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Quote:
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now this is a VERY good argument. quieter bikes do less damage to hearing than a loud pipe will. I even notice a difference on a stock bike vs aftermarket muffler, let alone straight pipes.
that true, gota wear ear plugs. once hearing goes, it dont come back.

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post #20 of 23 (permalink) Old 10-15-2007, 12:28 PM
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I was at the track yesterday watching my son ride his dirt bike and some kid removed the baffle on his RM85. It was loud as hell but you could tell he was lacking low end power.
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