need help on 440 kit

[big400boy]

i have a 2001 400ex that is bored over to 416. it has a stage two hot cams, a ported head, complete hot rods crank shaft, jet kit, and a full yoshi exhaust, i am looking to bore it over to a 440. i need to know what i am going to need to put in the engine to help out. i would also liek to know if anyone knows how a 400ex set up like this would stand against a 450r? thanks,

[drew416ex]

Well you cant bore the stock cylinder to a 440, you have to get a larger sleeve and have it installed then bored to 440. You can get a complete kit on ebay with piston, sleeve and gaskets. Depending on the port work, you will hang pretty decent with 450s, but I dont think you will notice a huge difference in power from your 416. The compression you decide to go with will make the most difference.

[big400boy]

so when i see on ebay where there is an auction for 440 kit with sleve ect. then i would have to press the old sleve out and press the new one in. and then that one would not need to be bored out right?

[TRXRacer1]

Your old sleeve needs to be removed, then your cylinder bored for the bigger sleeve and as far as I know your new sleeve will need to be bored to your piston size. If you go 440 get a bigger carb too. The 450r carb would work real well.

[big400boy]

alright thanks uv been a big help.

[BigBore24]

trxracer1 is right, once you get your bigbore kit you will have to press in the new sleeve then send it and the piston out to be bored. the other major things if they havent been done already are have the hd headstuds installed (I used helicoils on mine and havent had any trouble) and probably a heavier timing chain. some will tell you you need hardened rockers and such but its not critical

[big400boy]

ok and from where i am now to set up a sturdy set up how much do you t hink it would cost? liek to get it bored? cus i can get a kit just need the boring done.

[NacsMXer]

Originally posted by big400boy
ok and from where i am now to set up a sturdy set up how much do you t hink it would cost? liek to get it bored? cus i can get a kit just need the boring done.

Wiseco pistons offers 440 kits with 12:1 piston, sleeve, wrist pin, circlips, and gasket for $295. Might be able to find a kit cheaper if you shop around.

When I did my old 440 I ordered a new sleeve from LA sleeve and piston from Wiseco. I went to my local machine shop and had them press out the old sleeve, bore the cylinder, press in the new sleeve, and then bore/hone the new sleeve spec'd to the new Wiseco 89mm piston. It was around 80 bucks in all.

Price is really gonna depend on where you go though. The place I went to was a reputable shop that specialized in hi performance motors, so I felt it was money well spent. They even loaned me a ring compressor to help with the install.