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Why so many 2 into 1s on FXRs?

19K views 53 replies 20 participants last post by  pwmorris 
#1 ·
So I just picked up a 93 FXR and it has a pro pipe 2 into 1 exhaust on it. I have always preferred a traditional looking 2 pipes coming out of the same side. Although the pro pipe is growing on me. The guy I bought it from says the dealer sold it to him when he had a stage 2 kit installed. Says the engine needs the extra back pressure. I guess that makes some sense. Anyway, I have been looking at a lot of FXRs online and it seems that 2 into 1 pipes are pretty common on FXRs. Just wondering if there is a reason for these pipes being so common on these bikes?

Thanks
 
#3 ·
Maybe...Probably not....Probably because Most have had Exhaust problems...Poor quality from the O.E. ...mine rusted at the crossover in a Very few years...
Then everyone slaps Drag pipes on...they are Cheaper than Dirt....Then they decide to go Performance....and of course 2-1's make much better power than Drags...
For me....Good old O.E. [I use the pipes from Softails] with free flowing Mufflers, work Outstanding.
 
#7 ·
I've run 3 different 2:1's on my FXR and never felt they made more power than the duals I've run before.
I've had 2 different V&H Pro-Pipes, and an RB-Racing LSR Pro-Srock on it.

I ran the 1'st PP on the 80" Evo and the RB on the 113" as well as another PP.

I really WANTED to see/feel this extra power they say 2:1's make, but it wasn't there for me. My 80" motor ran terrible with it, NO top-end.

The 113" ran much better than the 80" had, but still limited the top-end significantly. I will say the RB-LSR DID make more bottom end than the duals I ran.
It would pull a wheelie in 3'rd gear w/o popping the clutch, where I'd have to abuse the clutch a bit to "get it up" in 3'rd with the 2" duals.
It's possible a set of 1-3/4" duals would have restored the bottom end there w/o the loss of top-end like the 2:1 though.

I like the look of them personally, it's the SOUND they make I can't stand. @ idle they sound fine, same with WFO, it's when you're cruising along without a load on it that's the problem. They sound like a dying Volkswagen or subaru engine with this awful flat tone. Yuck!

I couldn't live with it. It's the reason I pulled and sold my RB Racing LSR.
I really loved that pipe, as even though it lacked some top-end (it ran pretty good on top too) it made bottom end that would give you whiplash and was beautifully made.

In my opinion 2:1's make better bottom end (in most cases) but if you run your motor up to even 5000 RPM between shifts regulraly you're going to miss the top-end of duals. Also if you're like me and a significant part of the experience for you is hearing your bike's V-Twin engine as Milwaukee intended it to sound, you may have a real issue with the sound of a 2:1.
 
#8 ·
I like the look and sound of the 2into2 setups. I have a Cycle Shack staggered dual setup on my FXR4 now. Excellent power and loud. Before that I had V&H staggered dual pipes with megaphone muffs. Loud also (louder than the CS). Well made but had been poorly adapted to fit the FXR by the PO of my bike.

I agree the 2into1 pipes seem to even out that staccato V-twin sound associated with Harleys. I don't like the 2into1 sound.
 

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#10 · (Edited)
It might be because of whats out there for them. Drags. Single staggers, which are OK for putting around, but flow poorly due to the lack of a cross over. Short shots, which are just a look. And several 2-1 pipes.

So for performance, you either gut the muffs on an H pipe setup or buy a 2-1 pipe.

I'm thinking that there might be a way to use Dyna slip-ons with the H pipes. I'll need to work on that, and see what will have to be done to the muffler support. There are still some decent slip-ons out there with Dyna brackets on them.
 
#11 ·
Maybe because for a while, it seemed like there weren't many aftermarket choices for FXR's. Looks like a few new ones have been created recently.

I went with Supertrapp 2-1's a few years ago. Took some doing to get me past my love for staggered duals on Harleys, but I'm positive the engine runs better and after years of trying to take down the noise of duals without killing performance, well, 2-1's solved that problem.

I like the Supertrapp sound. Still "Harley" at idle and acceleration but a pleasant cat's purr at speed. Beats having my right ear ringing after a ride.
 
#12 ·
I think the choice is due to the lack of a good pipe for fxr's, it was for me. I have a large 113" engine and run it pretty hard, every shift is above 6000. It revs very quick, like flipping a light switch. Drags and sort shots drop me almost 30hp, most 2-1's even the one I use now, flatten out the power above 5000, it does not rev as quickly. So, we have to scrounge pipes for fxr's. I have a set for softails and a Dyna set, both needed brackets made for them. I need a good stepped set starting at 2" for the 113" ripass has the same issues I'm sure, now he is going larger to a 124" lol
 
#15 ·
Terry, depending on the quality of the end product and the PITA factor involved I might be willing to make you a set of the stepped diameter duals like I plan on making for my FXR's 124".

I may even make a few sets and sell them? But if I make more than one I'll offer the second set to you.

I'm going to use used NASCAR stainless pipe sections and probably Burns reverse megaphone muffs. They'll exit the exhaust port at 1-3/4" then graduate to 1-7/8" then 2".

Should make excellent top end power for nut jobs like you and me.
 
#17 ·
Andy, cool idea, and thanks, no hurry no worry here. All my friends think I'm crazy, poor them, I, know I am. It takes something special to use a 113" FXR. I know you know that. what is it with the guys that build big motors carry a dyno sheet and ride like 1000 year old, old women?
Brian, I think you got the idea, but don't get it. I don't want a set of pipes that reach a peak HP at a target rpm for maximum HP, while losing power in the mid range, that is for the table racers with the dyno sheets in their pockets. I want my cake and eat it too, I want power at all rpm ranges from idle through 7000. No loss, no dips, just power!!! It is difficult, not impossible. The set I have, does it, but it's getting old, worn and has been repaired one time too many. I have a great 2-1 but it flattens the power curve out before it hits 6000, so I miss the top end. I did one more repair on the "good" pipes lol. Rip knows what I'm talking about, power everywhere. I don't ride a dyno.
 
#19 · (Edited)
I will share the results and pics with everyone here.

I'm of the same opinion as Terry; you can have BOTH with a properly designed set of duals selected correctly for your setup. Horsepower AND torque, from bottom to top.

The dyno sheets will indicate better peak torque on a 2:1, but ENOUGH torque with some SERIOUS horsepower is a lot more fun to ride.

All 3 of the 2:1's I've run cost me big on the top-end. I've had good, properly designed dual setups that cost nothing @ bottom/mid range but tore A$$ up top too.
That's how I ride and what I need.


Now, that said, I will say aloud here that the power curve a 2:1 produces is probably better suited for your average rider and anyone more sane than Terry and I.

The RB-Racing LSR pipe actually did very well on top-end for a 2:1. Enough so that I'd have kept running it, IF it didn't sound like a dying 4-cylinder boxer engine. But the LSR is also going to be WAY too loud for most people too...
 
#20 · (Edited)
Either true duals or 2-1 can bring the money up top and give you all around power in the low and mid range, if it's designed correctly to fit the motors range, and how the motor and cam profile is set up.
I set up my stuff to work as one unit-from rocker boxes down to bottom end, and the pipe is simply one component to the whole package.
Fast street motors and track motors I've seen both run great-the key on the street is all around drivability and big top end- while not being insanely loud.

Years ago, I was on my old 124"- at the time I was running true stepped duals that Sam Wilis at Racing Innovations made for me.
I was up against a cocky big name builder with a 131" who brought his whole crew with him.
First thing I notice was that his pipe was too small for that big old motor, and sure enough, I put him and his crew on the trailer.

My current street FXR set up runs a 2-1, and gives me great all around daily driver power and huge top end, so yes you can have your cake and eat it too, if you are set up correctly with pipe and motor working as one.
As far as sound, it sounds great but even with baffle is pretty loud and is a screamer if I hammer it.
 
#21 ·
My current street FXR set up runs a 2-1, and gives me great all around daily driver power and huge top end, so yes you can have your cake and eat it too, if you are set up correctly with pipe and motor working as one.
As far as sound, it sounds great but even with baffle is pretty loud and is a screamer if I hammer it.
[/QUOTE]

OK....So the obvious question is, "What pipe are you running?". Maybe a pic too.
 
#22 ·
My current street FXR set up runs a 2-1, and gives me great all around daily driver power and huge top end, so yes you can have your cake and eat it too, if you are set up correctly with pipe and motor working as one.
As far as sound, it sounds great but even with baffle is pretty loud and is a screamer if I hammer it.
OK....So the obvious question is, "What pipe are you running?". Maybe a pic too.[/QUOTE]

JBV Racing-"Guppy"-but this pipe is for big inch motors only.



My old 80-96" FXR motors ran awesome with a Thunderheader, and there are some great 2-1's out there that make good all around power, but as the cubic inches climb, the choices become less and less.
Some guys are making their own big inch pipes which is great-as long as the correct baffle is used, combined with the right sized primaries (length and width) based on the motor.
 
#23 · (Edited)
Andy, i know the pipe will be awesome. Because you know what the crazies, like us, with the big motors need. Unrelenting power increasing from idle through 7000 or so rpm's. My rev limiter is set at 7500 to prevent an over rev on a missed gear or broken drive train component. The motors rev so quick, wow, the only comparison I could make would get me thrown out!!! Lol.
I agree with ripass, we can have it all. Torque is important, but not critical on the big motors for instance, on a bad day, poorly tuned with a bad pipe either my or Andy's 113or124, will make over 100ftlb torque, its not really an issue like with smaller motors. Sometimes I have to detune my motors to make them rideable, (breaking the tire loose while accelerating through 4th gear at 5000+ rpm's and 105-120 mph, is a bad thing) or whacking the throttle at a low speed in first gear, the front end snaps 4 feet in the air and you are white smoking the tire In a millisecond, gotta turn that down a notch!! Lol
I've tried probably a dozen pipes, all the 2-1's except the one I have now,shut the motor down below 5500 rpm's, most of the V&Has are less than impressive on the big motors, RB's are very good but LOUD. Supertrapp/kerker special built 2-1 is good revs to 6200, but???? And 1 set I have like40 hours in is awesome, Bubs Baddogs special made for my motor were awesome+, but ugly and fell apart quickly,(warranty was excellent, but broken all the time sucked)
So I'm looking forward to a custom set for high rpm large fxr's, thank god, or Andy!!
 
#25 · (Edited)
What I like about this one is that the two header pipes seem to be close in length. It seems most of the 2into1's have unequal length and that totally messes up the scavenging of one cylinder for the other. At least in theory. Thunderheaders are the worst in this area but they still have top performance. Just guessing but I think the reason why the TH has always performed so well is that they seem to have long header lengths and the baffles have no plates. The longer the headers the lower the power band rpm range and that helps mid range. This pipe reminds me of the Supertrapp except for the muff.
 
#29 · (Edited)
Not true-
I have seen Cycle Shack modified true duals pull 160 hp on a FXR and my old 2-2 pipe pulled 145 on my old 124" motor FXR as I mentioned in the above post.
My race bike runs 2-2's and makes a ton of power so either type of pipe can make big power, as I said, depending on a variety of factors.

As far as looks, my FXR with 2-1 pipe won a couple best of shows so maybe the pipe didn't hurt the looks too much.....
 
#27 ·
Period is a pretty strong word. Meaning that the results are carved in stone and cannot be strayed from. I know and agree that most of the time, your declaration is correct. But "period", every time, irrefutably, NO, not ever. I wish it was that easy. I've found in some cases the pipe diameter and the design of the baffle/s is more important than the number of outlets on the pipe.
 
#32 ·
For me, nostalgia has a lot to do with liking a two into one. The first time I saw an FXR with a pumped up 80 inch do a wheelie, it had a thunderheader. I have always loved the sound of a two into one.

Some people think I am crazy and they only like a two into two sound and look. This is one area where we are both equally right or wrong. Run what you like.

My problem now is finding a good performing exhaust that is not too loud.
 
#36 ·
fxr exhaust

Harleys are very sensitive to the exhaust. 2 into 1, 2 into 2 ? you want all the power in the rpm band where you ride the bike at.for most people, the quest for bragging rights to that almighty horsepower number results in a bike that is not very street friendly .I built a 124 evo for a guy, put it in an fxr and he rode it 150 miles in 2 years.It scared the hell out of him... he sold the motor to mike Roberts/bandit racing, I modified the heads for race only, put out 217 horsepower. that was the worst STREET MOTOR I ever built BUT the best race motor I ever built. by the way, 2 into 2 exhaust put out the best horsepower by far on this motor
 
#38 ·


Link posted on another thread, I like this for a couple of reasons. The rear pipe runs in front of the cam chest, my Supertrapp means I can only use half of the right hand foot peg and can get a bit uncomfortable on long trips.
Also with the merge collector I front of the pegs it means there's only one pipe running under the peg which has got to be good for ground clearance.
My only concern is with the collector where it is does that meat the lenght of the primary's are short? Does the system see everything after the collector as part of the muffler? I woldnt have thought so, there's no baffles in there......is primary lenght measured to the start of the baffles?
 
#39 ·
So what would be the best 2 into 1 for a 113" S&S for low end torque? Does someone out there make a pipe or is this something that would have to be custom built from my specs? Right now I have a Bassani Road Rage 2 into 1 for the stock 80" evo, but I think that will really restrict this motor. I wonder if it would be possible to modify the head pipes of the Bassani and reuse the canister/muffler?
 
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