440ex

[atver13]

dose anyone here a a 440 kit on theirs. i am thinkin about getting one do they overheat not reliable and hows the power compared to stock

[Thumpin440ex]

I think most of the 400 section is 416-440 bikes.. I never had had a issue.. If it is done right, use a oversize oil tank, it should be fine.. Hell alot of guys go to bigger heat exchangers, electric fans.. You will need to have the head studded.. If you do not issues will almost deff occur


John

[atver13]

who did urs? where do u get the bigger coolers from?

[SPE_Motorsports]

I used to run a mx 440 with a wiseco piston, if you are doing the build yourself there are a couple things to pay attention to. When torqueing the cylinder and head down, torque in increments so that the cylinder and head can move and stress relieve itself. Also after torqueing the cylinder, let it sit for a few hours then retorque. this will again let the cylinder move a bit so there isn't that internal stress in the jug. Do the same with the head, let it sit for a few hours after torquing, then retorque. I don't know what compression you plan on running, but make sure you LET THE ENGINE WARM UP!!! Many people just fire these high comp 400s up and hammer down and end up buring head gaskets out of them. The engine needs to warm up and allow the material to expand. By doing this on my own mx bikes the engines always ran flawlessly. I also just ran a stock oil cooler with air fins (because I got them close to nothing)... I hope this helps!!!!

[SPE_Motorsports]

Oh and makes sure you are in a normal "room temp" ~70* enviroment, if you are somewhere cold torqueing, the metal will be contracted and when the engine warms up, the engine may begin to be overtorqued and pull studs and bolts through the aluminum... just an after thought

[400exrider707]

More often than not the headgaskets blow from the headstuds pulling out, usually due to excessive heat and the aluminum in the cylinder breaking down. I would probably do the GT Thunder head studs regardless on a 440 build, match your cam with your compression, so if you're running high compression, make sure you have a good flowing cam to keep it cooler and run the correct fuel for the compression too.

I would not expect to just go on ebay and click "buy it now" on a cheap 440 "kit" then bolt it on and run it. Just keep reading here, you'll see what everyone uses and how they're built.

[quick89]

i just rebuilt the top end on my 440ex due to the wrong rings being installed. bought the bike about 3-4 weeks ago knowing it needed rings
i had to get a new cylinder because the old one was egg shaped. it was cheaper for me to go onto ebay and order a whole new cylinder that had all ready been honed and everything ready to go for the 89mm wiesco piston. it was 150 to my door and was a brand new cylinder. when i did the rebuild i also did do the gt thunder head bolts spend the extra money for them its worth it. the gt studs are allot better than the factory studs. make sure you run cometic gaskets another thing i did was coat the gaskets with coper seal just to make sure everything was sealed up right and torq to spec dont get in a hurry take your time. i also added another oil cooler to the bike so now instead of running just through the small factory oil cooler it goes through 2 oil coolers and the 2nd is prob 2x larger than the factory one.
also make sure that you run a synthetic oil this will help with heat displacement. 2 other things i plan to do is get the dip stick that has a built in temp gauge so i can monitor that and i may add an electric fan to the new cooler.
other than having some problems with jetting issues i have been very happy with mine runs like a bat out of hell
btw my bike is running 11:1 compression wiesco piston, stage 3 hot cams, head has been ported and polished and a couple of other odd and ends

[SPE_Motorsports]

Also when torqueing, put a dab of grease or oil on the underside flange of the nut or bolt. This is so that you are getting proper torque readings going into the thread/material and not the friction between fastner flange and the mating surface.

[400man]

Originally posted by SPE_Motorsports
Also when torqueing, put a dab of grease or oil on the underside flange of the nut or bolt. This is so that you are getting proper torque readings going into the thread/material and not the friction between fastner flange and the mating surface.

would this cause the nut to come loose over time.....putting oil on the threads? what about just using loctite or thread lock?

[SPE_Motorsports]

Originally posted by 400man
would this cause the nut to come loose over time.....putting oil on the threads? what about just using loctite or thread lock?

No, because the torque you are applying is through the bolt. You can use loctite or thread lock on the threads where it's needed. But i am referring the the flange area of the nuts and head of bolts. Where the head of the bolt or bottom of the nut meets the mating surface.

[400man]

oh ok, I see what your saying now..

[JOHNDOE83]

Originally posted by atver13
dose anyone here a a 440 kit on theirs. i am thinkin about getting one do they overheat not reliable and hows the power compared to stock

My 440 is over 5 years old, no HD studs, No bigger oil cooler, no oil cooler fan, NO heat issues. "jetting right will keep it cool"

Runs like the day it was built, never adjuted ANY valves "They stayed were I put them". I only been through 1 clutch and I drag race constantly and use regular car motor oil.

The power increase is REALLY nice!!!!

[kaleb]

I have a 03 400ex with a 440 big bore kit in it showed alot of difference from the stock performance but I also have a HMF slip on pipe on it

[Andrew170-440ex]

Hello i own a 400ex and it has many aftermarket parts on it including a 440 kit.. after tearing down the engine at least 5 times i learned that the stock studs do not hold because they stretch and strip the threads right out of the head. after tapping and drilling out the head we put course thread bigger bolts in because the owner of this bike before me didnt know what he was doing and farmer tightened every thing...:mad: so we pulled about 6 stripped bolts and studs out of the engine....MAKE SURE YOU USE THE RIGHT TORQUE SPECS FOR THE STOCK BOLTS AND YOU WILL DEFINITLY WANT TO DO THE THUNDER BOLTS OR YOU WILL BE REPLACING A LOT OF HEAD GASKETS..(We are on our third one not knowing what the problem was...)