Undertail
Thread Starter
Senior Member
SuperBike
Joined: Mar 2007
Posts: 1,611
From: Belgium, WI
Undertail
I have searched, and only found one example, for a undertail exhaust setup. I have seen the Mario Nava, and would guess that for most people this is cost prohibitive. I am in the middle of my undertail project and I am trying to figure out some of the routing issues like battery location, computer location, etc.
Any help would be great, and I will post picks as soon as I can.
Bill
Any help would be great, and I will post picks as soon as I can.
Bill
Administrator
World Champion
Joined: Dec 2004
Posts: 105,287
From: Fulton, MO
I think your best choice would be to graft the subframe and tail section of a bike that has undertail exhaust stock, ala CBR600RR/1000RR. All the tabs, battery box, etc. are already there, though you have to make sure the stock wiring harness reaches where they need to go.
Junior Member
Squid
Joined: Aug 2006
Posts: 17
hi Auto
plunging into this now myself, trying the RC51 rear end on my vtr, snatched a very very flat undertail from the states on ebay should suit my rear underseat exhaust i have in mind
post some pics when you can ill do like wise with mine
plunging into this now myself, trying the RC51 rear end on my vtr, snatched a very very flat undertail from the states on ebay should suit my rear underseat exhaust i have in mind
post some pics when you can ill do like wise with mine
Thread Starter
Senior Member
SuperBike
Joined: Mar 2007
Posts: 1,611
From: Belgium, WI
AAAARRRGGGHHH. Okay, my digital is not within reach by about 30 mi, BUT to let people know of the progress:
Saturday I cut the stock header, i carved the sh%# out of the undertail and made my own, and I have already sold my "stock" TBR (it came with them). I have the parts in from S&S headers, and the fabrication begins. Monday, in a stroke of genious, I came to the conclusion that the stock rear subframe could use an adjustment. So , it is getting cut and the right side is getting moved to the outside of the mainframe. Two reasons, clearance over the dual pipes coming up, and to keep from having to extend the passenger foot peg and having it become a wet noodle disaster. The glass packs are coming in today, and the mod begins on those parts. It is seriously frustrating that we have weather above 50 degrees, cause that is all I have ever needed to go riding.
Oh yeah, i looked at my RR in the undertail section, at the epoxy fill is cracking. Looks like I "have" to replace it
Saturday I cut the stock header, i carved the sh%# out of the undertail and made my own, and I have already sold my "stock" TBR (it came with them). I have the parts in from S&S headers, and the fabrication begins. Monday, in a stroke of genious, I came to the conclusion that the stock rear subframe could use an adjustment. So , it is getting cut and the right side is getting moved to the outside of the mainframe. Two reasons, clearance over the dual pipes coming up, and to keep from having to extend the passenger foot peg and having it become a wet noodle disaster. The glass packs are coming in today, and the mod begins on those parts. It is seriously frustrating that we have weather above 50 degrees, cause that is all I have ever needed to go riding.
Oh yeah, i looked at my RR in the undertail section, at the epoxy fill is cracking. Looks like I "have" to replace it
Senior Member
MotoGP
Joined: Sep 2006
Posts: 4,138
From: Austin, Tx
Very good! I am somewhat concerned about the two into one tho. I had always thought that the rear cylinder would exit straight away instead of looping back under the frame and then out. Does this not work? I'm sure you thought about this long and hard before you began but I was just wondering. It looks really good. Have you fired it up yet? The pipes are just straight out the back? My God, you'll raise the dead!
Thread Starter
Senior Member
SuperBike
Joined: Mar 2007
Posts: 1,611
From: Belgium, WI
Bill, I was wondering why one could not exit the rear cylinder up and out the back without going down and around the swingarm and then out the back. Then the front cylinder could be routed up through the swing arm in the hole that was originally used by the rear cylinder and out the back. This would completely eliminate bending the pipes around the outside of the swing arm. Thanks for writing. I am most interested in your project. I have followed some builds on the UKFirestorm site and yours is top notch! Full steam ahead! Bravo!
---NuHawk
10-4 good buddy,
The reason that I didn/t do that is that it would have drastically effected the tuning between cylinders. I would have had some positive effects, such as having two cyclinders with different torque peaks, thereby flattening the curve, but I saw it as more of a tuning nightmare. I could have done the Ducati deal and did unequal length, unequal diameter (but keep the volumes the same for both head pipes) but it would have been a PITA for merging or transitioning sizes for either a true seperate dual or a merged dual.
I also contemplated doing one undertail and one low side (next to or close to the engine/swingarm) ala GP style with no crossover, but then there is a loss of cross cylinder scavenging from the merge.
I like the results, but will have to see how it tunes.
---NuHawk
10-4 good buddy,
The reason that I didn/t do that is that it would have drastically effected the tuning between cylinders. I would have had some positive effects, such as having two cyclinders with different torque peaks, thereby flattening the curve, but I saw it as more of a tuning nightmare. I could have done the Ducati deal and did unequal length, unequal diameter (but keep the volumes the same for both head pipes) but it would have been a PITA for merging or transitioning sizes for either a true seperate dual or a merged dual.
I also contemplated doing one undertail and one low side (next to or close to the engine/swingarm) ala GP style with no crossover, but then there is a loss of cross cylinder scavenging from the merge.
I like the results, but will have to see how it tunes.
Thread Starter
Senior Member
SuperBike
Joined: Mar 2007
Posts: 1,611
From: Belgium, WI
So, called up Voodoo Motorsports for tuning and the conversation was funny.
Do you do exhaust coatings?
You mean ceramic?
Yes.
No. We have a scond party do our coatings.
OKay, well when I get my coatings I will bring my Bike in for tuning.
What do you have?
2000 Superhawk
What exhaust?
Custom 2-1-2 undertail exhaust that I made.
Who makes the exhaust?
I made it.
Yeah, no one makes those. Thats why I was wondering who made it.
Do you do exhaust coatings?
You mean ceramic?
Yes.
No. We have a scond party do our coatings.
OKay, well when I get my coatings I will bring my Bike in for tuning.
What do you have?
2000 Superhawk
What exhaust?
Custom 2-1-2 undertail exhaust that I made.
Who makes the exhaust?
I made it.
Yeah, no one makes those. Thats why I was wondering who made it.
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