How would an piped 02 400ex with elkas do against a stock (well both have nerfbars) 03 pred on the track?

In a drag the pred would obviously win because of its power advantage, but the 03 pred isnt the most reliable machine out there. (I'm scared if i accidentally powershifted or landed on the shifter out of a jump, that i blow the tranny out)

I heard the 400ex is a really fun wheelie machine, but that the 03 pred has trouble coming up cause of the long swingarm

One really important issue is maintainance. The pred is more of a race motor than the 400ex so it will need valve adjustments more often. How hard is it to adjust the valves on a DOHC motor? i heard you have to remove the cams to adjust the valves. On my 250, its just a 4 valve SOHC like the 400ex, i just have to take off the head. (nothing else to remove, it looks really easy in the shop manual)

How do you adjust the valves on a 400ex, do you have to remove the cam to? or just loosen a locknut and adjust a screw (or something like that)

And how often do you have to adjust the valves? 50 hours? 75hours? or 25 hours? On the pred its like 10-20 hours (to check them not always adjust) depending on how you ride.(hi revving aggressive, or grampa style slow)

Which do you think is better for me? (40% trail, 50%track, 10% random stuff like roads, gravel pits, field drags)

 

does nobody on here know anything about the 400ex? answer just one question and you're being a big help already

 

I have had experience with both machines.
In regard to the maintenance you mentioned, they are both on the same level. Most people let the valves on their 400ex/xr400r get all out of whack because they are afraid to tear open the top end to adjust the valves. The hardest part of the whole thing is to get the plastics and gas tank out of the way, I am sure it's the same on the predator. I check my 400ex valves every 20 hours, not sure what the factory suggests for either machine, but i can tell you that my ex girlfriend has a predator and NEVER had the valves adjusted and the thing still doesn't make any noise.
Personally I hate how my 400ex wheelies so easily, but the predator does feel like a tank in the front and the weight difference is noticable on the predator. The 400ex needs higher gearing to keep up with the top speed of the predator, but then you will find it needing more power to pull the higher gear ratio, and then you get into an engine setup like what I have in my profile.
In the trails, the predator is a bit wider that a 400ex with stock wheels, but the predator has better suspension from the factory. I put 450r front shocks on mine and had the rear shock set up for my weight to get it up to par. They both jump well though, but because of the weight you still kinda feel like you're jumping a utility quad with the polaris.

 

but is the valve adjustment on a 400ex the same as other SOHC engines? if it is the same as a crf250r i can get a friend to show me how to do it. Basically i want a quad that i dont have to bring to the dealer every 20 hours of riding to get the valves checked. (you have a hotcam, does that affect how often you have to adjust the valves, since the aftermarket cams are harder on your valves and valve springs?) How high does a stock 400ex rev? 8000rpm? 8500rpm? or 9000rpm? im guessing it doesnt rev too high since its a torque machine, and usually you dont have to adjust the valves as often if you dont rev it sky-high.

Sometimes you do have an amazing quad that is built on a payday friday and the guys who assembled the quad happened to get a huge raise in the morning coffee break. But im going to treat the quad how it should be treated according to the owner's manual, (except for the easy break-in period) so i would probably check the valves every 15-20 hours just like the 450s cuz its a higher-revving quad that makes peak power at a much higher rpm than the 400ex. (almost a 2 stroke-like powerband)

What would be better if i ride with 250 mx bikes?

 

a banshee.

 

banshee? on tracks? my friends said the lt-r450 and 450r could match the dirtbikes on the track, (though the ltr was better at it than 450r)

and doesnt a banshee completely SUCK on trails? cuz it stalls easily, has no low end, and a scary powerband for tight trails (the trails i ride are always under 25mph trails, and mostly under 20mph. im pretty sure a banshee would not enjoy going that slow, and i heard it punishes slow trail riders by overheating