2-1 exhaust question

mikstr · 05-04-2009, 11:28 AM

Hi folks,

Just trying to figure something out as it relates to my 99 Superhawk.

I have a moderately modded VTR1000 (ported and decked heads, Yoshi Stage 1 cams, lightened flywheel and many other goodies...; here is a pic from last year although it has evolved further since then: SuperHawk Forum - mikstr's Album: A study in evolution - Picture). After having run a set of Micron slip-ons for a couple of years (would love a full system, particularly by M4 but they are rarer than hen`s teeth...), I decided to try converting my bike to a one-off 2-1 set-up (based largely on the experience of some chaps in the UK who tried it). I am now running a single pipe (50 mm dia) directly from the collector (cleaned up the welds with a dremel) to a Blue Flame Dual Port can originally designed for a 98 R1.

The bike has been jetted on the dyno (DJ kit) with two long intake runners (to boost low and mid-range power). The torque curve now has a noticeable dip in teh 5-6.5K area, somethign I would love to get rid of. Any suggestions as to what might cause it and how I could rid of it? I know that the merits of 2-1 systems is a hotly debated topic but I did some reaserch on Google and found some dynos sheets of TLs and SVs running such systems and having flat torque curves so I would hasten to guess it is achievable. I was thinking of perhaps running a can with more back pressure (a single exit can of some sort). Anyhow, if all else fails I will likely go back to a 2-1-2 set-up with slip-ons but I would like to get this set-up working properly if possible.

thanks in advance
cheers

Kelevra · 05-28-2009, 6:13 AM

I like the mods!

What sort of power are you now getting with the cam mods etc? The RR forks etc was good thinking, did you use a rr triple clamp as well? Good fitment?

mikstr · 05-28-2009, 9:40 AM

My last dyno run with Micron slip-ons showed 111 hp and 70 lb-ft of torque (must remember the bike has 100,000 km at this point). With the 2-1, I saw the same top end hp but torque dropped slightly to 68.5 lb-ft, with a dip in the torque curve between 5-6.5 k.

I reently bought a full Akrapovic system on German eBay (still waiting to get it) and will be intalling that as soon as it arrives, a move that should bump output to about 115 hp or so. I will also be installng some 0.5 mm OS JE hi-comp pistons in the near future. When all is said and done, with a rebuild and the new parts, I should be good for over 120 hp and mid to upper 70`s in torque

BTW, my 2-1 will be for sale soon (sounds awsome!)