440 or 416

[400exrider1]

I want to know what would have all around power and speed the 440 or 416 kit for a 400ex.

[knighttime]

I recommend the 416 with xr cam.

[400exrider1]

WHY WOULD YOU RECOMEND ME TO GET A 416 KIT KNOW ONE HAS REALY TOLD ME A GOOD REASON TO.

[knighttime]

Get it because you will go faster and have more torque, and your quad will be more fun to ride.:D

416,,or go buy a new crf450 dirtbike and throw that motor in there..:huh :eek: :D

[ChadEXer]

Definately the 416!!

[Tommy 17]

416 bc the cylinder wallz are thicker, runs cooler, if u blow it up u still have 2 bore sizes above that, more torque, and revs quicker....

[Sparky416ex]

416

[Matt Fisher]

A 440. Larger engines make more power than smaller engines. Check Mickey Dunlaps comments on the idea that a 416 makes more power. Scroll down to TREX400's question. http://www.exriders.com/tech/askmickey1.shtml

In addition to making certain it's running enough compression, don't run a stock or XR cam in there. A GT Thunder, W Bros Track, HRC, etc will work well though.

[oynot400]

I have a 440 and love it. It has awsome power I recomend it to anyone. :D I agree with what Matt says also. I think that a 440, that is done right will walk over a 416. Then agian you have to ask yourself what you are going to to with it, race or trail? I do both with mine, but it is mostly trail ride and some hills. So if I was going to do nothing but race I would get the 416 or 426. The 416 may rev out faster, but it will not hold the power if you are trying to lug it up a hill. Remember there is no replacement for displacement. Then the one that gets me is some people say that the 440 is unreliable, HOG WASH! If you take care of you bike it will take care of you. So change the oil often and may be look into a oil cooler and or larger oil tank.
I hope this helps...

[400exrider1]

I mostly ride trails and on the road to go to my friend house to ride and i live in Ohio so the weather isn't always hot. But i want a kit that will last for a long time and be able to keep up with other modified 400 or what ever comes my way. ( i ride hard about 90% of the time)

Thank for all your guys help so far

[305exracer11]

i would go with a 416 or 425 because you can use stock sleeve and has all around power and speed if you do go for the 440 gt thunder is the place to get it done. if you go for a 416 or a 425 i would have it down at hetrickracing.com

[305exracer11]

you better get something if you want to keep up with me on our track...lol

[Dave400ex]

No Matter what Kit you get, 416, 425, or 440 you will have More Power then Stock. It really comes down to How Much You want to Spend. All the Motors will last a while if you Build it Right and Change the Oil and Adjust the Valves often. I will do a 416 myself. That is because of the Price though. If you have More Money I would get a Sparks, TC, Pro-Fab, or anybody else that has a 416 Motor Kit, a call. You should be Happy with whatever you do. I think a 416 Piston, Cam, Viton Valve Seals, Full Race Port and Polish, 39mm FCR Carb, and some more Stuff would be a GREAT Setup. Good Luck.

id say get a complete CT Racing 440 kit, comes wit ur choice of piston compression, bore, cam, new carb, rev box, gaskets, and some other stuff, really rips up