modified TBR exhaust

I heard a set of TBR 6-into-2 slashcuts and was blown away by the incredible sound (the owner later removed them because he thought that they were too loud).  That got me thinking . . . if the 34" packs on the TBR 6-into-2 canisters are often considered too quiet and the 17" packs on the slashcuts are often considered too loud, why not make some custom cans with mid-size packs?  Plus, the TBR cans allow for tuning of the sound by increasing or decreasing the fiberglass matting.

One problem: I like longer stacks.  I called around to find 4.5" tubing (either steel or aluminum), but came up empty.  I then noticed a set of the older (circa 1997) TBR 6-into-2's (unused!) on the VRCC classifieds.  Perfect!  The glass packs are about halfway between the slashcuts and the new cannisters.  They have 4" cans, allowing me to use my trusty DynaFlex truck stacks from Airflow Systems for those nice, long tubes.

Here are some pictures of the system -- true collector, big headers, and crossover tube.  Note that the old TBR system had chrome heavy-gauge steel headers (as opposed to the current thinner stainless) and 27" cans (WAY too short for a Tourer or Interstate w/bags).

Modifications

If you have read my other pages, you know I can't leave well enough alone. 

First, I could not live with the  inevitable bluing.  So I cleaned them up and shipped them off to Jet Hot for treatment with their Sterling coating.  It looks like polished aluminum.  In fact, you polish it with aluminum polish.  And the Jet Hot coating keeps the tubes much cooler, providing a tad more power and lessening the chance of burns.  I also took the opportunity to add some O2 sensor bungs in each collector (more on that below).

The original (old) TBR aluminum 27" tubes were scrapped in favor of some 38" Airflow truck stacks.  Note that Airflow now does custom lengths, with the chroming being done after cutting to seal the cut ends.  There is a substantial weight penalty with the Airflows, though, adding almost 20 lbs of weight to the system.

The truck stack ID is a perfect match for these older 4" TBR cans.  I had to grind the flange off of the rear end caps so that they would slide down into the cans (27" guts in 38" cans).  I just ground them down enough so that they would pressure-fit into to stacks.

The front caps are also just pressure fit.  I toyed with using LaMonster's glasspack bolting arrangement, but that would have interfered with driving the rear cap in from the front.  And at least with the TBR straps, I knew that there would not be any prototyping issues -- because these cans are not going to come apart easily.  I actually concaved the front caps pounding them in.  I think that everything is pretty much in there permanently now.

Well, I got the headers installed fine, but I could not get the hardware to mount the cans to line up.  So I decided to give TBR a ring.  The guy on the phone could not help me, as he had only been there about a year and was not familiar with the old system.  He tells me that he will have someone call me back.

About an hour later, I get a call from Craig Erion himself (one of the Two Bros).  He could not figure out the problem over the telephone, but since I am only about 30 miles from TBR's Santa Ana HQ, Craig offered to take a look at it if I would come down.  So I show up two hours late.

Next thing you know, Craig is getting a lift and crawling under the bike.  Craig, a former Valkyrie owner, spent two hours tweaking the exhaust until it was right.  He even stayed after hours to finish the job.  Now THAT's customer service!  Bear in mind that we are talking about a 1997 system that I bought second hand in 1999 and completely reworked.  TBR owed me nothing, yet treated me like a king.

The results are perfect -- throaty, but quiet idle.  Just at the point where nearby car alarms are chirping, but not going off.  Blip the throttle, and it sounds like a big-inch sport bike.

But at WOT, it sounds like the world is coming to an end.  As someone once observed regarding another exhaust, "it sounds like a cross between a big block Chevy and a Porsche 911."

I may have picked up a little HP, but it's hard to tell.  Louder always seems quicker and I don't trust butt dynos.  But who cares -- I just wanted the delicious sound!

I do know that it hits the rev limiter much easier than it used to, so it must be making more power up top.  Stock, you can tell that the engine is one the North side of the torque curve, so you pretty much can feel when to shift.  With the TBRs, it just keeps on pulling to the redline.

I am installing two Autometer air/fuel ratio meters --one for each cylinder bank.  Combined with the adjustable DynoJet needle kit and K&N, I am hoping to be able to use these to get the mixture right.