Thanks for the replies everyone.
I do have a rear diff from a different bike - from a Suzuki VS1400 Intruder 2.69 vs the stock 3.09)
I do have a 5th gear already installed from a Suzuki m50 (.804 vs stock .81)( approx, as I am away from my home data base right now), it helps but I need to reduce the rpm a bit more to get peak hp at xxx mph.
I have figured that most of the Suzuki transmissions are the same therefore (spacing of shafts) I have been looking for a Suzuki Madura transmission for 18 months, they have a nice .75 ratio on their 6th gear,...not found one yet. I am also trying to track down an EU spec secondary gear, as its 31:30 vs USA spec 30:30...3% isnt much but its about what I need. Considering it may cost $500 I am not put off.... It cost me that much plus a little more to get the drive hub modified and installed....
Could anyone tell me what kind of steel might be used for this kind of application?
Cheers
Alan