440 Big bore kit

[Bwetzel55]

I'm considering buying a bolt on 440 big bore kit. I've been reading the other posts about the kits but i'm not sure what all i need to do it. Also how unreliable will it make my EX. Also how high of a compression can still run 93 pump gas.

[honda400ex2003]

11:1 will be about it on pump gas. As for reliability issues, if it stays cooler it is good, if the bore was done properly that is a plus, along with using quality gaskets like cometic 89mm gaskets you would better your chances of keeping the motor running. An addition to making it more reliable would be hd head studs also from gt thunder. this would prevent head gaskets blowing which is a very common misfortune with the 440s and high comp. other than getting a kit make sure you have the desired parts in the kit or get them such as a stage 2 cam or something. an hd cam chain is also good for reassurance to be sure you will not break one. a crf 450 cam chain is good along with the hd 400 ones which are basically the same thing as the 450 one. hope this helps out a bit. steve

[mtrombla08]

i put a bolt on 440 kit on my bike. it was an 11.1 wiesco piston and i used cometic gaskets. i havent had any problems at all. i would definately recommend a hot cams stage 3. i dont know what else you have done but mine rips hard. i also have k and n filter and outerwears cover on filter and airbox. Also runnin full hmf competition exhaust. i have the best wheelie machine out there. i would say go with it. just make sure u get jetted correctly. i run 93 pump gas.

[Xplorer99]

i got the 440 kit on ebay. im still putting it together. deffinatley get the GT Thunder headstuds!!! if u buy the new cylinder like i did that is already bored to 440 then it doesnt come with studs...so just makes sense to put HD studs in lol. get a fan and keep it cool and it should be very reliable...


hey honda, im looking at getting a HD cam chain. what specific one would be needed? i want the heaviest duty i can get haha

[mineralgrey01gt]

crf 450 chain will do just fine. I have one in mine and you can definitely tell a big difference between that and stock, any year will work. I think mine is for an 02

[Xplorer99]

Originally posted by mineralgrey01gt
crf 450 chain will do just fine. I have one in mine and you can definitely tell a big difference between that and stock, any year will work. I think mine is for an 02

ok thanks alot, just wanted to make sure i bought the right one

[mineralgrey01gt]

no problem at all, goodluck putting it back together!

Also from looking at the cylinder wall on that cylinder you got off of ebay, does it look like it has any bores on it after that?

[88dunerider]

i got a 440 bolt on stage 3 cam, k&n , full hmf comp series exhaust no problems with her yet besides she does heat up a bit i think youll be satisfied if you get one

[Xplorer99]

Originally posted by mineralgrey01gt
no problem at all, goodluck putting it back together!

Also from looking at the cylinder wall on that cylinder you got off of ebay, does it look like it has any bores on it after that?


i thought 440 was the bigest you could go, it has a namura sleeve in it, ill go take a look at it. i think there should be plenty enough to bore it out a little more... ill go take a look tho and see how thick the sleeve is

[JOHNDOE83]

Also order some really big jets...mine has a 220 in it.

If I were you Id get from 190 - 215.

[mineralgrey01gt]

Originally posted by Xplorer99
i thought 440 was the bigest you could go, it has a namura sleeve in it, ill go take a look at it. i think there should be plenty enough to bore it out a little more... ill go take a look tho and see how thick the sleeve is

i know in a stock cylinder that the 440 is the biggest bore but I was looking at those and wondering since they come with the 440 sleeve, if they would have any bores left. If I keep this bike, id like to see what a custom piston would do in it, like a piston a couple sizes bigger than 440 would do on a stroker motor on one of these

and yes get big jets to be on the safe side. I should have listened to JOHNDOE83 the first time I went through it lol. I have a 205 in mine

[Bwetzel55]

Thanks guys for all the info. I'm definitely gonna get a 440 bolt on big bore with GT head studs CRF 450 cam chain 11.1 wisco pistion, cosmetic gaskets, and a hot cam. Which stage should I get? I'm hearing people running Stage 2 an 3. Whats the big difference between the two and which one should I run in my setup. All i'm running right now is a HMF comp. slip-on and a kn filter, im also gonna get a hmf head pipe.

[mineralgrey01gt]

do you want more bottom end or top end? The stage 1 handles bottom end well and doesnt loose too much on top but with all that at once done to it you wont notice the difference. Stage 2 (which is what i have) is great mid to top, mine pulls extremely well 4th and 5th. Stage 3 i think is more fit for your motor, big bore motors and such. I think thats what kept me from getting one from hot cams from their description

[Bwetzel55]

K i'll go with a stage 3 hot cam. I priced every thing out. It came to around $850 just for the parts. Never thought i'd spend that much on my ex lol

[togup]

I took my jug to the machine shop to have a new 89mm LA sleeve installed and the old 89mm namura removed after he installed it he told me i could have bored it out bigger than 89mm, the question is how much more?

[mineralgrey01gt]

89mm is a 426 right? or is that a 440? Im anxious to see. If you could get a piston custom made to make a 460 then throw in a stroker crank, that would be just sick power

EDIT: nvm i saw its a 440. I think if I wanted. I could get someone to custom make a piston, maybe wiseco, JE, etc. Ill have to email them and see

[togup]

I talked to a rep at CP and he said he would build to what ever spec i needed i told him ill just stick to 89mm for the moment

[Xplorer99]

Originally posted by mineralgrey01gt
89mm is a 426 right? or is that a 440? Im anxious to see. If you could get a piston custom made to make a 460 then throw in a stroker crank, that would be just sick power

EDIT: nvm i saw its a 440. I think if I wanted. I could get someone to custom make a piston, maybe wiseco, JE, etc. Ill have to email them and see

I could be wrong but isn't the 460 stroker a 440 with stroker crank? So if u could bore it more than 89mm and throw in a stroker crank u would have a huge motor!!! I'd buy a custom piston if someone would make one

[mineralgrey01gt]

Originally posted by Xplorer99
I could be wrong but isn't the 460 stroker a 440 with stroker crank? So if u could bore it more than 89mm and throw in a stroker crank u would have a huge motor!!! I'd buy a custom piston if someone would make one

that is true. I was thinking somewhere along a 480 stroker maybe even a 500 stroker. I dont know how to figure up what the stroker cc output would be but it would be one potent engine. Probably wouldnt last long but man it would be a beast for a little while