V-Twin Forum banner

1 - 1 of 1 Posts

250 Posts
Discussion Starter · #1 ·
This is a cheap fix for that low end torque sag from drag pipes (no crossover) when you want to run em on the street but also do the drag on weekends.
Make a "tunable baffle" by taking a 3/4" outside diameter washer and weld it to the top of a 3/4" x 1/4" bolt. It should look like a candy sucker with a 5/16 hole in the middle. Now Drill a 1/4" hole on the bottom about 1" from the end of the drag pipes. Take the "tunable baffle" and place a 1/4" nut and a lock washer (away from the large washer)on it. Now insert your "tunable baffle" into the inside of the exhaust pipe and add another lock washer and nut on the outside to hold it.
If you don't have access to welding equipment, try this handy little trick from the folks at Bike Tech..
Use 1/4" x 1" thumb screws which can readily purchased at any local hardware store for about $ 0.50 a piece. They work great. The "football" shaped head on the screws measure approximately 3/4" x 1/2" so they have about the same surface area as the 3/4" o.d. washer because of the lack of the hole. And they do not require any welding.
You tune the baffle by changing the angle of the thumbscrew or washer to the exhaust pipe. For maximum torque, the washer will be at 90 degree angle to the pipe. For maximum horsepower the washer will be parallel to the pipe. Torque at 3000 will be up 5-10 and HP at 5500 down 2-4 so this is a street vs drag adjustment.
For your neighbors, the pipes will also be quieter at 90 degrees.
This is from the "I like free" bag of tricks.
1 - 1 of 1 Posts