Anybody have an opinion on head pipe torque inserts?

46th, I'm running a very similar setup, as you kinow. MMM recommends exhaust port inserts for improved flow and outlet inserts to correct peak torque rpm for overly large ID of 1.75" pipes. I'm not arguing the point, but that combination works for me. MMM mentions welding the outlet inserts in place. I drilled and tapped for two 4 mm. screws with countersink heads in each pipe, countersunk the holes so the screw heads sit flush with the pipe, an installed with blue Loctite. Screws can't back out in any event because the mounting flanges of my 17" megaphones cover them. I'm very pleased with the performance.
This whole discussion makes me wonder what would actually be preferrable. An overly large header (1 3 /4" OD) with TPO and EPO vs 1 1/2" or 1 5/8" OD pipes? Or maybe a stepped or tapered header, starting at 1 1/2" OD / 1 3/8" ID at the port, and 1 5/8" or 1 3/4" at the muffler connection? At least, a smaller straight/ stepped/tapered pipe would be a bit lighter, due to less material and no extra bits added.
 
This whole discussion makes me wonder what would actually be preferrable. An overly large header (1 3 /4" OD) with TPO and EPO vs 1 1/2" or 1 5/8" OD pipes? Or maybe a stepped or tapered header, starting at 1 1/2" OD / 1 3/8" ID at the port, and 1 5/8" or 1 3/4" at the muffler connection? At least, a smaller straight/ stepped/tapered pipe would be a bit lighter, due to less material and no extra bits added.
Cost is the consideration. A 1 3/8 or 1 1/2 pipe is best for midrange, 1 3/4 better for top end. A stepped pipe would be expensive to build and buy and most of us are tighter than a Scotsman's wallet. The torque inserts are a clever and functional way to make commonly available pipes work well for our needs.
 
I put a set of the smooth taper inserts on madness with 1 3/4" headers but made a bunch of other changes at the same time.
It had a 10 pound hammer at 5K to past redline powerband, now more suited to sane street riding.
high compression 750, cam, porting etc.
 
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I'm using 1-3/4" OD pipes with outlet inserts only because I don't like the quality of plating on the chrome pipes that have been available for the past few decades and couldn't find stainless pipes in 1-1/2" OD. Sometimes we compromise....
 
I'll just toss in here that Norton 750-850s use 1 3/8" headers........
some choices are more about fashion than performance.
Wide tires, fat pipes, etc.
Fat stainless pipes look very cool! Rumor has it they perform very poorly on the street.
File that under “stuff I learned on the internet.”
 
Gee, Marty, I had no idea that my bike performs poorly--thanks for passing that along! (Seriously, I suspect that many of those observations were posted by guys who know just enough to hang the pipes and whose knowledge of tuning reduces to a mishmash of advertizing hype and urban myth).
 
Cost is the consideration. A 1 3/8 or 1 1/2 pipe is best for midrange, 1 3/4 better for top end. A stepped pipe would be expensive to build and buy and most of us are tighter than a Scotsman's wallet. The torque inserts are a clever and functional way to make commonly available pipes work well for our needs.
Gee, Marty, I had no idea that my bike performs poorly--thanks for passing that along! (Seriously, I suspect that many of those observations were posted by guys who know just enough to hang the pipes and whose knowledge of tuning reduces to a mishmash of advertizing hype and urban myth).


I recall reading a pretty well considered treatise on headers and a tapered pipe was thought to be the "best" answer to improve "extraction". But yup 'tain't cheap to taper a pipe.
 
Gee, Marty, I had no idea that my bike performs poorly--thanks for passing that along! (Seriously, I suspect that many of those observations were posted by guys who know just enough to hang the pipes and whose knowledge of tuning reduces to a mishmash of advertizing hype and urban myth).
Well, I'm following your lead! I have the inserts for the head, and the other inserts for the back of the pipe from 650 Central. I'm assuming I'll be sufficiently "optimized."
 
Race tuners look for what's going to yield that last .01 pony that might make the difference between a win and a loss, and a few guys with serious knowledge and equipment might enjoy the challenge of designing and building a stepped system, but for the rest of us street riders, obsessing over the optimal exhaust is a trap, and we settle for good enough. My 40" head pipes are theoretically around 8" too long. Does that mean the motor gets all choked up at higher rpm? Uh, no. It has plenty left when the tach hits 8K (haven't wound past 7500 except on a few tuning runs), and there's plenty of throttle left when the instruments say 118 mph at 7K rpm, which as fast as I've felt like pushing the bike. Wait, that doesn't sound right....
 
Ya'll can run whatever pipe size you want with all the inserts you want but if you're not running the high performance emgo air filters you're wasting your time.

But really I'm loving the info here as I have a 2 into 1 system but am eyeballing some pipes and the inserts if my headers turn blue, which I suspect will happen almost immediately.
 
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