Cross over pipe
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4th Gear
Joined: Dec 2021
Posts: 8
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From: South Carolina
Cross over pipe
Had to pull my rear master cylinder off and to do this I had to pull the rear exhaust pipe off,it has stock exhaust with a crossover pipe,I noticed that the crossover pipe was closed on the inside. Is this normal and if so what's the purpose of the crossover?
Thanks
Thanks
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From: Honah Lee
Welcome from North Beach, FL., USA! 
Just in case you have not done both of these two important items!
Be sure to add an Avatar of your favorite shot in the USER set up for the small picture others will see in the top left corner of your post with your USER name.
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Purpose is so each cylinder shares both exhaust. This works well on a two cylinder that fires opposite of each other. One cylinder helps clear the exhaust from other cylinder.
On stock exhaust, it's just a small pipe on back side connecting the two headers. Obviously, if it's plugged, someone did it. Didn't come that way.
Just in case you have not done both of these two important items!
Be sure to add an Avatar of your favorite shot in the USER set up for the small picture others will see in the top left corner of your post with your USER name.
And most importantly a Signature Line in your USER set up for your bike model, year, and all the letters that Harley recognizes it with that others see at the bottom.
This enables others to know your exact model if you ever ask a question or another member interested in it may ask you a question about it.
Purpose is so each cylinder shares both exhaust. This works well on a two cylinder that fires opposite of each other. One cylinder helps clear the exhaust from other cylinder.
On stock exhaust, it's just a small pipe on back side connecting the two headers. Obviously, if it's plugged, someone did it. Didn't come that way.
Last edited by Jackie Paper; Jan 3, 2022 at 07:03 PM.
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Joined: Apr 2018
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From: Florida
On the early model Evo FXR like my '86 the balance pipe was not aesthetically pleasing. The crossover serves as a balancer and IMHO the bike runs better with it. Not a big difference but a difference. Later they reconfigured and hid the crossover so you could not even tell it had one. The first thing most people did on the early Evo FXR's was put on an aftermarket exhaust system that did not include a crossover. A lot of my friends went with a 2 to 1 header which also balances the pressure and they run great on the Evo or even a TC for that matter. I have never heard of one being plugged from the factory. I am interested in finding out if someone knows what's going on with your bike. I would lean towards someone altered the crossover somehow.
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Great topic. Thank you, OP.
'20 Heritage with a hidden crossover pipe on stock exhaust. I'm trying to learn the reasoning for a cross over pipe. I'm thinking the following but do tell me where I'm wrong -
- Allows both cylinders to use both mufflers during exhaust stroke reducing noise and back pressure
- Provides a vacuum doing value overlap to salvage any exhaust from the intake value of next cylinder to fire
Several explanations I read said that a crossover pipe gives a slight increase to torque and HP at low and mid range RPM. I assume this happens due to the two benefits above?
'20 Heritage with a hidden crossover pipe on stock exhaust. I'm trying to learn the reasoning for a cross over pipe. I'm thinking the following but do tell me where I'm wrong -
- Allows both cylinders to use both mufflers during exhaust stroke reducing noise and back pressure
- Provides a vacuum doing value overlap to salvage any exhaust from the intake value of next cylinder to fire
Several explanations I read said that a crossover pipe gives a slight increase to torque and HP at low and mid range RPM. I assume this happens due to the two benefits above?
