Join Date: May 2002
Location: calgary, alberta
Motorcycle: 1991 GSXR 1100. 1988 Katana 600/'86 GSXR 1100
'Race' exhaust, first gen vs second gen 1100
Perplexed by my findings so far on various header tube diameters on 86-88 1100 vs 89-92 1100. Wondering if anyone can shed some light...
I have two sets of Yoshimura 'race' headers for the 1052 motor. One is on my 1109, and one is a duplex on the shelf. They both have an O.D. of 41mm on the header tubes( I will be selling the duplex once I repack and re-sleeve the slightly scratched cannister. But I digress...)
I have a Yoshimura 'street' system on my '91 1127. It has an O.D. of 38mm. I know it is designated a 'street' system as I talked directly with Yoshimura and they identified it as such with the serial/model #.
My confusion is that I can not find any headers/full system for the 1127 motor, of any brand, that has an equally large diameter header tube. I spoke with Hindle, and Akropovic, and both of their 'race' systems have an outside diameter of 38mm. ???
I find this baffling because either there is something mysteriously different about the 1127cc motor vs the 1052 motor that would dictate a smaller diameter header tube for RACE situations. I understand a smaller diameter header will be more street friendly with the preservation of the mid-range from higher exhaust gas speed etc. But I can not understand why a RACE system would be that much smaller.
And btw, at first glance, 38mm doesn't sound much smaller than 41mm, but it surprisingly represents a 15% difference in cross sectional area.
OR, these supposed 'race' systems are not actually so.
Does anyone out there own a header/full system for an 1127 that has a 41mm O.D., or larger, header tube diameter?
btw, the reason for all this curiosity, is I love the performance of the 41mm Yosh header on my 1109cc '86 motor. I don't feel any compromise in the midrange and I want to reproduce the same on my 1127, soon to be 1216.
Any feedback, info, witty banter, semi-critical feed-back is welcome!