440 Big Bore kit w/Stage 2 Hotcam

[bkelley]

I was thinking about getting the Wiseco 440 Big Bore kit (http://www.jciracing.com/honda-400ex-9908--440-big-bore-kit-wsta40099084402.html) for my EX and had a few questions. First off, how difficult of a process would this be? I've been around cars and bikes my entire life and know my way around a garage pretty well, but I've never done something as extensive as this. I figure I need to learn this at some point, so why not now? I'm just afraid I'll screw something up in the process. I mean, anyone can break an engine down, but putting it back together is a different story. My dad isn't too fond of the idea, either. His motto has always been "if it ain't broke, don't f**k with it."

Also, what is the difference between compressions? And which is better? 11:1 or 12.5:1?

Thanks for all the help, guys.

[dalejiw25]

"if it ain't broke, don't f**k with it."

[rob_990]

if u wanna run pump gas go with 11:1

[bkelley]

Yeah, I'll stick with 92 or a mix of 103 and 92. Wish I could afford to run some VP or something.

[bkelley]

So, do you guys think I will be able to handle this with my Clymer manual and any other included instructions?

[trailrider894]

you must research this before buying the kit.... make sure you are getting the bore that is best for you .... and don't forget that the engine must be bored out by a professional in order for the piston to fit into the cylinder...

[dyechainsaw]

Here is a link so you can download the service manual

http://www.exriders.com/vbb/showthread.php?s=&threadid=402551&highlight=service+manual+400ex

[bkelley]

Originally posted by trailrider894
you must research this before buying the kit.... make sure you are getting the bore that is best for you .... and don't forget that the engine must be bored out by a professional in order for the piston to fit into the cylinder...
The kit I'm looking at comes with a new Namura cylinder sleeve so no machining is necessary.


Originally posted by dyechainsaw
Here is a link so you can download the service manual

http://www.exriders.com/vbb/showthread.php?s=&threadid=402551&highlight=service+manual+400ex
I have the actual Clymer manual.

[miles Machine]

if it just comes withthe sleeve you WILL need to have someone machine it to install....but if its a cylinder youll be all set

[bkelley]

So I'd be good with this kit? (http://www.jciracing.com/honda-400ex-440-big-bore-kit-w-cylinder-and-stage-2-performa4004402.html)

[Chukkinsod]

If you go with a 440 set up, I highly recommend GT thunder or other Oversized studs.....or you will pull the studs with any compression

[bkelley]

Hmm... maybe this is more work that I want to deal with. I plan on getting a new quad within a few months (700XX or 450R), I just wanted to give my 400 some more power in the mean time. Plus I'm going to keep it anyways. Maybe I'll just stick with the Sparks key and a CDI box for now...

[miles Machine]

not sure what com the 440 kit is but even at stock like mentioned i would deff get the gt thunder studs

[TRXRacer1]

Originally posted by bkelley
Hmm... maybe this is more work that I want to deal with. I plan on getting a new quad within a few months (700XX or 450R), I just wanted to give my 400 some more power in the mean time. Plus I'm going to keep it anyways. Maybe I'll just stick with the Sparks key and a CDI box for now... The kit you showed is a solid deal. Don't let the head stud thing scare you, any decent machine shop can install some threaded inserts in you cylinder then you just re-use the stock studs. You can thank GT Thunder for the stud scare. Attention is needed but it's not as big of a deal as some would think. Studs have been re-anchored since the begging of engine mods.

[bkelley]

I just don't want to dump ~$500 into my 400 if I am going to be getting a new bike here soon. That could be going towards stuff for the new quad. You know?

[TRXRacer1]

Totally understand but if you're still itching for a boost get an advanced timing key. Cheap, fun power.