I have a yz400f 99 and i just purchesed a second hand white brothers e series pro meg and im also putting a 13.5:1 comp piston in it, im looking for more top end and i have 9 plates for the pipe, i have to repack it should i pack it really tight?. I have herd the pipe dose not require jetting. Should i jet it cus there is bog from idle when i snap it on quick. I mostly ride around sea level & i have not done any carby mods, should i ???? im doing the head gasket cus it was chewn about 100ml of water every hour. ive put on a 1.4 cap and it slowed the loss of water a bit but then i spotted some oil in the radiator!!!!!!!!!!!!!! will the higher comp piston make it run hotter???? if so whats the best solution. ive herd about some additives ( water wetter, some sort of crystals ) do they work or are the radiators just to small. i would like to keep the same radiators cus they are quiet expensive. the water looks like it flows well so i think the water impellor is fine. I do some 3 to 5 hour trail rides and i want to stop worring about running it dry and cooking it in the middle of the bush!!!