It sounds like we are much alike LA Ryder.Im also a long time rider who always wanted a B4 but just recently bought mine.Heres my input after 8 straight months of riding and modifiying my B4, which I bought nearly bone-stock in Feb.
Gearing......getting 6500 rpms at 80mph is gonna put you at a serious disadvantage when accelerating.I added one tooth up front and dropped one in the back (equivelant to dropping 4 teeth out back) and Im still running 8000 rpms at 80mph.It didnt really affect my acceleration but 1st gear is actually usable now and Im not screaming on the highway.But,I must downshift a couple gears when passing or trying to speed up.....its just a fact of life with a high strung little 400,youll just bog and go nowhere if you "roll on throttle".You must gets revs up to make things happen.
Tuning......B4's are tuned quite badly from the factory.A hot thermostat is a good place to start,it will get the engine up to a usable temp and make tuning easier.The early water cooler Suzuki engines ran notoriously cool and it makes them cranky when lean.Running better at higher altitudes sounds like lean tuning,which is pretty common.After installing the recommended thermostat and a FactoryPro jet kit,my B4 runs like a champ in all conditions and its MUCH more fun, having no dips or bumps in the power.Both mods are easy/cheap and have been covered MANY times before,so a little searching will net you the needed info.
Pipe......I didnt like the loud,harsh nature of the Yosh pipe that came on my B4.I easily adapted a late model ZX-6 high midpipe to my B4 with just one weld,and then I stole the Hindle Stealth muffler off my FZR1000.The tone is awesome and the amplitude is exactly proportional to the throttle input. If I want to stay quiet,I stay out of the throttle....but when Im into it and the revs climb,she screams.
Suspension......I just finished dialing in my suspension the other day,and its just awesome.Taught suspension and a tucked riding position have their downsides,but I bought this bike for the exact same reason you stated....for short distance,aggresive canyon riding and track use.The 90's GSX-R front suspension is an easy swap and fully adjustable.I used an 07' GSX-R 750 rear shock that is nearly a bolt on.I had my spring sag set the other day and now its even better than before.Brakes are just RIDICULOUS......the 6 piston dual fronts will, with one finger,haul this little bike down from triple digits like hitting a brick wall! On a track,you could probably late brake anything out there.There are lots of tire choices out there,and an SV650 rear wheel will allow a 160 tire in back,if your inclined to go wide with the rubber.I did that mod,along with a GSX-R400 rear swingarm a couple weeks ago.Still gotta get the pics of that up.....
It wasnt cheap in the long run,Im sure I spent more than the cost of the bike.But spread out over time made it easier,and bargain shopping for used Ebay stuff helped save money.For the big ticket items like tires and my new Scotts damper,I whipped out the ol' plastic!
