I finally got my '81 r100rt started today and took it on it's maiden voyage after sitting in my buddie's storage barn for 7 years. It needs more tweaking and probably needs the valves set tomorrow, but my problem is that on my 25 mile ride today I could not get the bike to shift into 5th gear. No grinding, no nothing. I found a neutral between 4th and 5th, but no 5th gear. All shifts between the first 4 up or down were pretty darn smooth for a 32 year old bike, but no 5th gear. Any ideas?