Has anyone tried different exhaust systems and felt or measured different performance characteristics between the brands? The reason I ask is a friend also had a 98, both bikes jetted the same. Mine Two Bros.,his round Jardine high mounts. When we would swap bikes I would get back on mine thinking WHATS WRONG WITH MY BIKE.His would pull hard right off idle while mine felt kind of flat until about 3500.We ran them back to back on the same dyno and his showed a perfect arc from 2500 to redline while mine was flat until 3500 and thenstarted making power. From 4000 on up they made identical power.We swapped pipes and the results followed the pipes,so it wasn't the bike.His had 13,000 mi.,mine had 35,000 mi.

 

Well I would have said differences in carb setup, however if you swapped exhausts and the results followed I'd have to say the high mounts make more power lower and broader over the rpm spread.

I'm sure 8541Hawk will fill in some gaps for you and me. I have Hindle high mounts, that according to one source add about 5hp but I have no real proof of that or where that HP starts.

 

I swapped to a set of D&D low mounts from high mount Jardine carbon. Absolutely NO difference in power/acceleration etc. that I could tell seat of the pants. Louder for sure!

What are the chances the 2 bikes were set up exactly the same? There are so many variables, tps etc.....

 

Yeah that's a tough one... could be a number of things, including placebo

Or could be that they are both "tuned" for high-mounts, but the brand of slip on I couldn't see making a noticeable difference.

 

The mufflers themselves on a 4 stroke will not make that much of a difference. Do you know what the carb specs and jetting were of each bike? It could simply be that the setup of both pairs of carbs favored the characteristics of the jardines.

 

The dyno clearly showed what I felt,the Jardines made more power on the bottom end. It had to be either the length or pipe diameter. I jetted and set the TPS on both bikes. I had the jetting and TPS figured out by 2002. I posted the TPS tip back in 2002 on the Micapeak site and even sent it to Motorcycle Consumer News which they printed giving full credit to Factory Pro. Before we switched pipes I thought I would duplicate his jetting. He was the 3rd owner when he bought it in 2004. Wrong!!! When I checked his carbs I found the mixture screws at 3 1/2 turns out,45 pilots The stock 178 main in the FRONT carb and the 175 in the REAR carb and Dynojet needles in the 6th groove,oem filter. His plugs were black with fuel and it still ran better than mine. I just wondered if anyone else had experienced similar results between different brands.

 

I have tried almost every exhaust made for these bikes over the years on several different superhawks and I have never had one of them cause the bike to not run properly or have any flat spots. In fairness I did own a '98 GSXR600, a former supersport race bike (105 at the wheel), with a full akrapovic exhaust. When I'd swap the muffler for a vance&hines muffler it developed a horrible flat spot @6k rpm that would completely disappear when I put the akrapovic muffler back on. Never experienced this with a superhawk though...

 

Is the packing tight on the two bros? Loose packing or burned packing will cause minor performance issues.

 

The packing is and was good,i"ve repacked them 3 times already. I just realized yesterday was my bikes birthday. Bought it new 8/30/98. 83,000 mi later, she still gives me thrills !!!

 

You're giving me too much credit.....

Anyways, from what I have seen, there really is no big difference between any of the "open core" slip ons.

If there are baffles in them it's a different story.

The different shapes just have a bit different sounds.

As for high vers low mounts, first on this bike it is a "looks" thing as the first hard part to touch down is the header in right hand turns.

So unless you have a Mori STG2 header and oil pan (which relocates the header to the center line of the bike) high mounts are not really needed, though they can look good.

Now for power, actually you are going to lose 1-2hp going to a high mount system with all other things being equal.

The reason for this is that you have made the exhaust system longer so it is no longer "tuned" to work with everything else.

The difference is so small that most would not notice it but that is what the dyno runs I have seen showed.

So all in all there is no more than 2-3hp difference between any (high or low mount) slip on system IMHO.

 

Your right about the peak power output,they both peaked at 104HP at the same RPM. I don't remember if Jardine offered a choice of street or race baffle.I beleive when you looked into the outlet that you could see an extended tip of the core.Similar to the stock pipes except larger OD. I still run my original Two Bros. I installed 14 years ago and was considering something different. I guess I could put the stock pipes back on and go stealth mode.

 

Yeah, Jardine offered both at one time... I have the highmount race version, which is most defintely a perforated 2 1/4" pipe, straight shot, nothing hampering flow, and very little to hamper noise as well...

Your Two Brothers exhaust should also be a perforated pipe, straight trough, nothing else... Either you have a baffle in there, or the inside pipe has come loose, and is blocking flow, if you cannot look straight through it...

 

As one well known, sometimes controversial East Coast tuner likes to say about different slip-ons, "A 2" hole is a 2" hole." A 2 1/4" hole is a 2 1/4" hole" The point about baffles fracturing internally has happened to a friend twice on his full Muzzy, aluminum round can on his '02 FZ-1. I've had a SuperTrapp Internal disc baffle fracture on my old '94 CB1000f too. Like having a potatoe or tennis ball jammed in the muffler.

 

Mine are straight thru,I did find the posts that hold the core in place on the end caps cut thru from vibration letting the core to drop down.I had that repaired about 5 years ago.