ok well i have options here. i have an 05 400ex with an fmf powercore 4, dnyo jets, rev box. Im also going to have it ported and polished. I might sell it and get a 450r. Should i sell the 400ex and get the 450r or keep the 400

 

If you are a tighter trail rider, keep the EX. If you ride faster more open trails or wide open country, get the R.

 

Like reconranger, I have both a 450r (2006) and a couple of 400ex quads. I have the 450r setup for the track and the 400ex for the trails. For the past year, I have ridden the 450r almost exclusively. Last weekend, I went trail riding at George Washington National Forest. I couldn't believe how much the 400ex vibrated and how my hands felt after 3 hrs of riding...slight numbness from the constant vibration. It was running great so I know there isn't anything wrong with the 400ex...just not as smooth as the 450r engine.

I am thinking of getting my wife a 450r for the trails now as a test...and then one for me if it is that much better. I always thought the low torque of the 400ex made it perfect for trails and it is such a bulletproof engine. I would either go for the 450r so you don't need much in terms of engine mods (the HRC kit is plenty for 90% of the riders) or leave the 400ex stock as possible. It really isn't worth trying to muster too much performance from this engine.

Anyhow, my 2 cents.