How Long Of A Pipe

I Was Wonderin, I'm Going To Up Size My 1 3/4 Drags To 2". My ? Is I Want To Take The Old Pipes And Fabricate Them Into Some Short Custom Pipes. How Long Should They Be Before It Becomes A Valve Issue? Are The Short Pipes On All Those Custom Bikes Just For Show? If So, What's The Point If You Can't Ride It.

Pipes

Sportsterboy,

IMHO the shorty curvy pipes are for show only. One of the requirements for entering these bikes into shows is they have to ride them in. I would presume they run ok for a short distance but, have you ever seen any on the road?

They do run shorty pipes in the drags but they compensate with extra fuel. They also don't ever heat up in the quarter. They are still only mildly warm.

That's my thoughts. I used to run 1.75" X 42" straight drags open and got along very well. I did run a rich mix to protect the valves then put in 4" baffles. I liked the baffles better for performance and only lost the painfull part of the exhaust note. Not much difference IMO. I never heard of cones back then.

Later,
Softtail

IMO, V&H makes some good shorties also. I have the Bigshot shorts on my Dyna and love em'.

Sporsterboy, IMO, you best bet is to stick with a pipe that is known to work with your motor. As hrk mentioned, the stepped headers are the way to go for short pipes, (alleviates a lot of the sonic & thermal pulse issues), but costly. Again, IMO, your motor isn’t big enough for a 2” pipe to work effectively, your exhaust velocity will slow way down.
My .02

Pipes

Seems like there is some rule of thumb about pipe size vs cubic inches. If you are big on inches the 2" pipes are OK but if your are running 88" or 95" engine its best to stick with the 1.75" pipes. That's not the voice of experience, just what the "experts" say. There is a magic velocity where the exhaust system works best and pipes that are too big slows the velocity to a level below that.