Is 440 Kit worth it?

[Dizing400ex]

Hey guys,

Ive heard of the 440 bore kit for the 400ex and im wondering if its worth it. A friend of mine told me that the 440 kit is making like 38hp just boring the stock engine with stock components for like $300...

true???

Hows the reliability with the 440 kit?

also, I planned on going with a rev box, timing advance, HRC cam, port polish, K&N filter w outerwear and dynojets, curtis sparks X-6 full exhaust...

Is this setup better than going with the 440 kit? more or less reliable??

thanks,
Dustin

[Joe400ex]

i personly wouldnt go with a 440. I would go with a 416 or 426 way more reliable. Plus a 416 feels like a 440 and is more realiable.440 runs to hot and has its ups and downs

[underpowered]

if you run a 440 on all stock components you will not get 38 horsepower. You need all the other stuff you listed (cam, pipe, CDI, K&N, ect..) to really make a 440 work well. Like Joe400ex said, a 426 or 416 will be more reliable and run just as well if not better than a 440. A 416 will not have the torque of a 440, but will run cooler and rev much quicker. I have a 426 and it is in my opinion the best of both worlds. it revs quickly but is also very torquey. I would say start off with the pipe, cam, CDI, jets, and K&N then bore it when it needs it, not now.

[dirtmomma]

We bought a 440 for our 400 also but instead decided to go w/ a 426 :) we've had it in for about7 months now w/ no problems, we just didn't have the $$ to go w/ all the other extra goodies to make it a GOOD/TRUE 440, my oldest son just started racing it in our winter FT series & he's there w/ the 450's :D:D once he gets used to it I think he will do real well on it!!
I'd go w/ a 426 you can always go bigger but it costs more to go smaller :eek: LOL

[440racer66]

heck yeah its a good upgrade ive had no problems or over heating and i ride hard i would not run it stock thought

[Bigun55]

My winter project is gonan b the 440 kit, Go 4 it, my buddys run it on theres and it dont run them hot and them boys ride em hard.

[slamdak8782]

easy upgrade with good reliability. 426 revs better 440 is a torque monster 426 is actually faster. Go figure

[wheeltrax]

i love my setup, works well.. torque monster too. it pulls in every gear.

[QuadJunkies]

I have had no problems what so ever with my 440 ... :)

Was it worth it???????? YES!!! :blah: Ive had the 426 also, I keep it for a back up kit ...both are GREAT kits, but I think my 440 gives me more top end and less on overheating

well u arnt going to have 38 hp if u have the stock muffler and header. stock 400ex's come with 25-28 hp. a 440 kit isnt going to git u that 38 hp. u would have in the mid 30's but u could take 2 stock 400ex's and put the same it in em and one might have more power than the other one.

440s are susposed to blow head gaskets.

[QuadJunkies]

Originally posted by blue450yo
440s are susposed to blow head gaskets.
not if you do the research and get the right kit? ;)

[tooanxiousii]

Do guys know anybody that ports heads good ?

[QuadJunkies]

Originally posted by tooanxiousii
Do guys know anybody that ports heads good ?

I had mine done locally so I wont be of much help on that.

[dirtmomma]

Originally posted by QuadJunkies
I had mine done locally so I wont be of much help on that.

Ditto :) our machine guy did my 300 & my brother did our blaster!! If I were you I'd look for a reputable machine shop & talk w/ them :)

[slamdak8782]

one thing that helps to keep them from blowing head gaskets is to have your machinist leave the sleeve out a couple thousndths to hold the head gasket inplace