Hi all Have a problem with the mixture on my 98 wr400,inspected the plug and is black so can only assume that this is far to rich,running fmf iv silencer so does the jetting need looking at? also the main air screw /knob on the side of the carb is fully turned in but this bearly gives me a tick over & the bike fails to idle for road junctions etc. I basically need simple good advice as I'm relative new to the bike. Any thoughts greatly appreciated. p.s I live in England so would the altitude + climate make a difference? Cheers Davey WR400 98 Morad sm rims,Talon hubs pro taper bars bark busters crd bash plate,crd frame guards,motovisionracing grapics,recent piston ,rings,valves,vacum carb plate,magneto coils.