Back in the late '80's there was a tech bulletin that was put out by the folks at Yamaha R&D. It was a trail port job, shaved head, a shortened Y-Pipe and an internal muffler mod. Pat Hauck was known to do this mod for customers that asked before he was his own dealer while he worked for Motorsports of Rice Lake. I heard through the grape vine about this mod during a time when many people were piping their Exciters in the late 1980's to keep them in the game with the Indy 650's etc. I got ahold of Pat and ordered a brand new 1990 Exciter from him at Motorsports and had the whole update done. The sled was a bit faster than my dad and uncle's 1987's with the early version (good 8200 rpm version) PSI twin pipes. Traction was my biggest issue. My gut was this was the inspiration for the SX model.
About two years later I made the mistake of buying a 1992 Exciter II LE. Oh what a mistake......after some time and much $$ invested I found out you could not do squat with an Exciter II because Yamaha purposely detuned the 1991-1993 Exciter's with the ignition. Piping, porting.....nothing made that sled wake up. I finally asked Pat Hauck at an ice drag race how he got his 1991 to run so good. Here he finally told me he had to throw a 1987 ignition cdi on it. He had the same problems until Yamaha let him know.
I dumped the 1992 the next year and bought a 1993 SX, that sled I had for 4 years and had nothing but good experiences with it. I did swap the crappy 40 pound 3/4" Yoko track out with a 1" Camo Challenger that hooked better and weighed 32lbs so it spooled up quicker. I ran a Bender single pipe on it, the only SX purpose made pipe made by either AAEN or Dynoport, not sure. No more top end but crisper mid range and pulled an extra 2 lengths in the mid range during testing over the stock pipe. It sounded better, started better and was much lighter. The YXR primary was rather new and still had those white nylon plastic slide sleeves in the towers which caused binding. I swapped to a Comet 108C with either a tall Comet blue or a Polaris red spring (either worked) and 10M weights (49 grams) with the 87X belt. Motor needed nothing as Yamaha put the beans to this one, aggressive porting, shorter intake neck and flat slides for wicked throttle response, much like a YZ dirt bike response. That sled I could take out any triple piped Polaris I ran across, Storms, RXL's, Ultras and the Ski Doo's of the time. Never ran a 700 Cat though. It pulled over hard so for the heck of it I did a compression check, 150 psi per cylinder!! Yes Yamaha required premium fuel on this one. My understanding was they only made around 1300 of them.
