Just so we know what exactly we are talking about here is what the TT regs say...................



d) Machines
All motorcycles must comply with Appendix B of the ACU National Sporting Code Group A1 for solos and Group B2 for sidecars and with these TT Supplementary Regulations. The onus of ensuring the eligibility of any machine rests solely with the competitor. All Superbike, Superstock and Supersport machines must be on the 2008 FIM list of homologated motorcycles.

- TT Superbike Race
For machines complying with 2008 FIM World Superbike regulations and/or 2008 MCRCB Superbike regulations with the amendments specified in Appendix A of these TT regulations.
Over 750cc up to 1000cc 4 cylinders 4 stroke
Over 750cc up to 1000cc 3 cylinders 4 stroke
Over 800cc up to 1000cc 2 cylinders 4 stroke


- Sidecar TT Races
For machines complying with Formula Two Sidecar regulations as specified in Appendix B of these TT regulations.

- TT Superstock Race
For machines complying with 2008 MCRCB Superstock regulations with the amendments specified in Appendix D of these TT regulations.
Over 600cc up to 1000cc 4 cylinders 4 stroke
Over 750cc up to 1000cc 3 cylinders 4 stroke
Over 850cc up to 1200cc 2 cylinders 4 stroke


- Supersport Junior TT Races
For machines complying with 2008 MCRCB Supersport regulations with the amendments specified in Appendix C of these TT regulations.
Over 400cc up to 600cc 4 cylinders 4 stroke
Over 600cc up to 675cc 3 cylinders 4 stroke
Over 600cc up to 750cc 2 cylinders 4 stroke


- Senior TT Race
For machines complying with the following specifications:
• TT Superbike
• TT Superstock (without limitation of tyre choice)
• Other machines admitted at the discretion of the Organisers