I konw its been talked about before but my YZ400 is boiling over in a pretty fierce way in tight trails. Background: I picked up a 98 YZ400 with a 420 kit in it from a friend of mine who has had it sitting for the past 3 years. My intention is to use it as a dualsport bikefor desert and trails and during the time of year when I cant ride my 04 CRF450 in OHV areas. I'm running a WB E-series full ststem with 6 discs in it. I did the grey wire mod and it starts and runs real well. Problem: I've had it out twice now and the first time I had no problems pretty open trails hot weather and around 5000 ft. (Hungry Valley SVRA). Second time out was at Coral Canyon OHV area, Hot weather, 3000ft and very tight very rocky kick your type stuff. Sometimes you have to stop and wait for somebody to clean a section so you can get a good run at it. I boiled it over like 4 times to where it was raw steam coming out of the overflow. Is this common with the YZ400 when ridden like this? I was a little scared because I don't want to waste the motor and if I can't trust it in that kind of terrain I will sell it and get a bike that can cope. How much will something like Engine Ice or Water Wetter help and is there anything else that might help? Sorry this ended up being long and thanks in advance for any guindance.