My brother in law bought a 96 XCR 600 awhile back.. It has SLP rail extensions and a different track, but I am trying to determine what size track it had stock and what it has been extended to.. I do not know the process for measuring to see what length a track is. It cant be extended by too much since it still has the stock tunnel extension and couldnt be more than a 136.. Can anyone tell me how to find this out? Thank you