I've had this bike for a year now and just found this website. I have a whole slew of questions I'm hoping someone can help answer, first a little about the bike. 2000 WR400F, Dunlop 759, YZ gas tank, CEET seat, Accell tipple clamps, bars, FMF Ti-4 exhaust with stainless mid-pipe (stock header), stock gearing, no air-box and I rejetted UP two sizes after the exhaust on both the primary and the (idle?) needle (sorry, I don't remember off hand - I'm at work now). I have the stock WR tranny with 14/50 sprockets, stock suspension (stock settings even) and I still have the coolant overflow tank. Things seem fine but compared to the YZ450's and CR450's I see while riding the bike feels as though the bottom end isn't quite the same as on some of the other bikes. This weekend I'll take a look at the grey-wire and redo that, I'll also look into doing the YZ cam timing but I'm not sure I'll tackle that myself. With that all said, anything that can give me more bottom end grunt? Sure I can put a new sprocket on (14/50 now) as I had planned on going to a 14/52 or 13/50 combo soon. I heard that the motor has a heavier flywheel weight that slows it down a little to smooth out the power. I *think* I'd like to get rid of this but I can't find anything in the manual that talks about flywheel weights. I've found the section on the balancer - is that what everyone referrs to when they talk about adding weight to the flywheel? Secondly I'd like to remove some weight from this bike. I am not sure how much it weighs but it's fairly heavy. I rode a friends YZ426 and it felt quite a bit lighter though his bike is far from stock so it's hard to tell if it's better handling, lighter or both. Are aluminum subframes worth the money? I've removed most items I don't need for moto action to save weight but would glady remove more if it's not needed. Yes it's an enduro bike NOT a motocross bike but really I wanted a YZ with the WR tranny so I bought a WR and changed tanks and plastics to drop the obvious weight differences. I would like to keep the coolant overflow on except as a last resort to keep from having my bike burp my fluids out at an inopportune time. Also, if there's anything other than the already helpful thread on free-mods that you think might help me out please as away. Thanks for any help you might have.