longer exhaust

[harold dent42]

Harold this may help, I built several pipes about ten years ago using different length head pipes, the best performing pipe for low end torque had a 16" head pipe. Mine helped on the top end too. If you measure any of the pipes sold on ebay or Amazon the head pipe will be close to that. Those pipes are way better than a stock pipe if you add a silencer, without a silencer they are too open for stock jetting and are way too loud, I welded 6" of a gutted stock muffler on mine. The single rear mounting strap is not enough, I welded a second strap to the front of the pipe and both use the same mounting point.

thanks greg that helps alot

 

[YetiWoodz]

I built a 36" and 38" pipe. I believe a 32" to 36" overall length (not including stinger) is ideal. Longer = more torque, but less hp. Stinger should be a smaller ID than the header.

 

[harold dent42]

I built a 36" and 38" pipe. I believe a 32" to 36" overall length (not including stinger) is ideal. Longer = more torque, but less hp. Stinger should be a smaller ID than the header

thanks that helps alot, im thinking ill make mine around 36" how would i be able to muffle it without it losing power if thats possible? im fairly new to these bikes lol

 

[Karl Snarl]

thanks that helps alot, im thinking ill make mine around 36" how would i be able to muffle it without it losing power if thats possible? im fairly new to these bikes lol

Mufflers work pretty good for muffin sound. I'd try that first.

 

[Street Ryderz]

thanks that helps alot, im thinking ill make mine around 36" how would i be able to muffle it without it losing power if thats possible? im fairly new to these bikes lol

I'll just leave this here,
L = E x V over N
Where L is the tuned length, in inches
E is the exhaust-open period, in degrees
V is wave speed, in feet per second
N is crankshaft speed, in revolutions per minute
For example, in an engine with an exhaust-open period of 180-degrees, and a
power peak at 7000 rpm, and using the 1700 ft/sec figure for wave speed, then,
180 x 1700 over 7000 = L 43.7 = inches
That length is, I must again stress, measured from the exhaust port window back
to a point slightly more than halfway down the baffle cone at the end of the system. You will never get the full potential of the engine by just fitting the pipe to the bike without using this formula first, also there is a proper ratio for stinger I.D. which effects the temp in the pipe and therefore the wave speed! This is .58-.62 x the head tube dia, so if you have a 28mm I.D. head tube the stingers I.D. should be 16.24 - 17.36mm.




View insights
170 post reach


2Lowell Ray and 1 other

 

[toojung2die]

Hello all, ive been riding my bike quite a bit recently and ive been wanting to change the exhaust so it comes out behind me, i wanna do this for looks as well as a quest for more power and of course fun. anyway the idea im tampering with is taking an old stock exhaust and cutting it in half then extending it with a length of pipe, i know that a pipe like that exists but it would be more fun to make it. the only thing im really worried about is it hurting my power band. any tips, suggestions, or questions? if you have anything to say about it please do i love to learn. have a good day

I had the same idea. I made this exhaust from a cut up stock muffler and 3/4" EMT tubing. It didn't change the top speed but the bike would climb hills noticeably better than with the stock muffler. It also made the exhaust much quieter. The loudest sound the engine made was coming out of the carburetor intake.

 

[harold dent42]

I'll just leave this here,
L = E x V over N
Where L is the tuned length, in inches
E is the exhaust-open period, in degrees
V is wave speed, in feet per second
N is crankshaft speed, in revolutions per minute
For example, in an engine with an exhaust-open period of 180-degrees, and a
power peak at 7000 rpm, and using the 1700 ft/sec figure for wave speed, then,
180 x 1700 over 7000 = L 43.7 = inches
That length is, I must again stress, measured from the exhaust port window back
to a point slightly more than halfway down the baffle cone at the end of the system. You will never get the full potential of the engine by just fitting the pipe to the bike without using this formula first, also there is a proper ratio for stinger I.D. which effects the temp in the pipe and therefore the wave speed! This is .58-.62 x the head tube dia, so if you have a 28mm I.D. head tube the stingers I.D. should be 16.24 - 17.36mm.


View insights
170 post reach
2Lowell Ray and 1 other

woah, thanks alot. i had no clue there was all of that going into a custom preformance pipe, im definently going to do more reasearch and give this more thought than i was originally, your bike looks bad to the bone.

 

[harold dent42]

I had the same idea. I made this exhaust from a cut up stock muffler and 3/4" EMT tubing. It didn't change the top speed but the bike would climb hills noticeably better than with the stock muffler. It also made the exhaust much quieter. The loudest sound the engine made was coming out of the carburetor intake.

thats exactly what i was thinking of doing with my bike, i have alot of hills in my area so the extra tourque would be nice lol. what does your top speed look like with that pipe?

 

[Karl Snarl]

I'll just leave this here,
L = E x V over N
Where L is the tuned length, in inches
E is the exhaust-open period, in degrees
V is wave speed, in feet per second
N is crankshaft speed, in revolutions per minute
For example, in an engine with an exhaust-open period of 180-degrees, and a
power peak at 7000 rpm, and using the 1700 ft/sec figure for wave speed, then,
180 x 1700 over 7000 = L 43.7 = inches
That length is, I must again stress, measured from the exhaust port window back
to a point slightly more than halfway down the baffle cone at the end of the system. You will never get the full potential of the engine by just fitting the pipe to the bike without using this formula first, also there is a proper ratio for stinger I.D. which effects the temp in the pipe and therefore the wave speed! This is .58-.62 x the head tube dia, so if you have a 28mm I.D. head tube the stingers I.D. should be 16.24 - 17.36mm.


View insights
170 post reach
2Lowell Ray and 1 other

If you ever wonder why we love you, this is why , oh master of the smokers.

 

[toojung2die]

thats exactly what i was thinking of doing with my bike, i have alot of hills in my area so the extra tourque would be nice lol. what does your top speed look like with that pipe?

That was ten years ago and I sold that bike. Top speed was 30 mph but the vibration was wicked. It was a smooth cruiser at 20-25 mph. The eBay engine I bought in December doesn't vibrate as bad at top speed. They must be balancing the cranks better. I might make another exhaust like that for the new motor bike.