upgrading to a 440 piston

[bigdady536]

If i upgrade to a 440 piston what other stock parts need to be replaced as a result of the upgrade, if any need to be replaced.

[BEAVER.989]

Your cylinder will need to be re-sleeved. That's about it.

[bigdady536]

will the re sleeve need to be done at a motorcycle shop or a machine shop.

[BEAVER.989]

Yup. There are places you could send it off to, as well... like LA Sleeve, or GT Thunder, I believe.

[honda400ex2003]

The rest of the stuff is not neccessary but recommended, like hd studs if you are going 11:1 compression, a new cam chain, and a cam for more power. I forgot to look at your sig to see if you have any aftermarket stuff but they are all good things to do. Also some valve seals would be good too if it has had some hours on it. Good cams depending on where you want your power to be are hotcam stage 1 and 2. 1 being lower and mid, and 2 being some low, lots of mid, and some top. steve

[bigdady536]

when i upgrade do i need to be careful on the timing issues of the motor or is that easy, to configure.

[unitednations]

Timing on the 400 is really simple. Line up the marks.. i rebuilt mine sooo fast

[honda400ex2003]

It is very easy to do, just line everything up right and you are set. The only time it will ever change is is the flywheel is moved such as putting in a sparks timing advance key or something. steve

[dariusld]

The 440 is alot easier to get wrong then the 416. I would do a 416 instead.

[MtnEX]

At some point when I was looking around, I saw some "bolt-on" 440 kits for the EX.

In other words, the kit was a whole new cylinder re-sleeved and bored for the supplied piston/rings.... I'm thinking all the gaskets too...

Tear yours down, install the gaskets and piston, set the new jug on, the put your head on....


Has anyone ever done one of these?

[rideracelivemx7]

i installed one on my friends quad, you have to hone out your block its self to fit the new jug that comes with the kit, a dremel and a nice vaccum will do, its time consuming, hone the crap out of the block and smack the jug on with a block of wood if needed on the rough spots, personally i dont think jsut the bore kit is worth it, its torquy yeah but not worth just the bore, th cam is what made the difference

[Snipe]

Well a cam and bore work together, just doing a cam works against the motor to a point and just a piston will help power but the 2 together is a must they go hand in hand.

[MtnEX]

Originally posted by rideracelivemx7
i installed one on my friends quad, you have to hone out your block its self to fit the new jug that comes with the kit, a dremel and a nice vaccum will do, its time consuming, hone the crap out of the block and smack the jug on with a block of wood if needed on the rough spots, personally i dont think jsut the bore kit is worth it, its torquy yeah but not worth just the bore, th cam is what made the difference

Dang, I was thinking that would be an easy "quick-change" option for a rebuild... cylinder service delivered in a box basically...

But I forgot about the bottom end needing modification for the 440.

[rideracelivemx7]

no modification of the lower end besides honeing the hug hole for the 440 is required, you migh tbe thinking of the a stroker kit, and the crank and counter weight i belive? have to be shaved.