Advice on 440 build

[mattl31]

I’m trying to build a good quality 440 motor for my bike, and am faced with 2 different ways to approach it.

#1

New 440 cylinder from eBay 179.95
New JE 12:1 440 piston from eBay 154.95
Cometic gasket set from CT Racing 34.95
CRF timing chain from eBay 40.36
GT thunder head studs from GTT 55.00
-self install studs
Machine shop bore cylinder to piston specs 50.00?

TOTAL: 515.21


#2

New 440 cylinder, JE 12:1 piston, and gasket set combo 439.94
CRF timing chain from eBay 40.36
GT thunder head studs from GTT 55.00
-self install studs
No machine work?

TOTAL: 535.30

Obviously the price difference in negligible, but I am curious what you experienced builders would recommend. If I'm going to be installing head studs to either new cylinder, is it a good idea to have the cylinder machined, or do the studs have no effect on the fitment between piston and cylinder?

Let me know what you guys think

[HondaRacing83]

whatever you do, do the crf timing chain either way

[mattl31]

Originally posted by HondaRacing83
whatever you do, do the crf timing chain either way

absolute must with a 440 build. i want to build a reliable one and know that a hd chain and head studs are not optional!

[Thumpin440ex]

You can find that chain for 2x bucks.. What gasket kit does the JE kit come with?? what Jug does it come with.. For 20 extra bucks you know what your getting, OEM jug, a good kit..



John

[mattl31]

where are you finding the cam chain that cheap? the price i have listed includes shipping so maybe tjats why it seems high. and as fas as i know, both of the above listed cylinders are aftermarket castings, as theyre listed as "new" cylinders. only way to end up with an oem cylibder would be a resleeve, which id prefer to not do.

[Thumpin440ex]

Let me do a little digging. I just finished my 440 last april(2010) I picked it up I believe for 27 bucks or so..


John

[CJM]

So your going to run race gas? 12:1 means 100 octane or better.

[mattl31]

Will be running it on VP 110 octane race fuel. Did so even with the 11:1 piston in it now.

[HondaRacing83]

off topic question but how high compression can you go before you have to run race fuel? highest we have here is 93 octane

[trxPOWER]

I would go with the new big bore cylinder no question. gets you a thicker sleeve plus new alumiumn to work with

[mattl31]

Originally posted by HondaRacing83
off topic question but how high compression can you go before you have to run race fuel? highest we have here is 93 octane

Some may consider me to be a little conservative, but given the hot blooded nature of these motors I'd say 10.5:1 to 11:1 would be the ragged edge on pump gas. I think ideally at 11:1 a mix of race gas and pump gas could achieve desirable results.

[2muchquad]

Race fuel requirements for compression isnt set in stone.So many times i see posts on here when i think people truly have no idea.My "buddys quad" need this or "i ran 100oct" on 10;1 for peace of mine yadda yadda.Truth be told CAM overlap is gonna have a say in this.A big cam with more valve overlap is gonna let compression "bleed off" negating the need for race gas in some instances.I ran 93 pump in my yzf mx bike and it was 13.5;1 compression.It was liquid cooled though.thats the difference.I would hesitate to run 12;1 on pump in a air cooled motor with a hot cam.I would definately run a xtra oil cooler and bigger tank though to help cool.;) heat should be considered when build performance air cooled motors.If these 400s get too hot your power will drop considerably.;)

[mattl31]

Originally posted by 2muchquad
Race fuel requirements for compression isnt set in stone.So many times i see posts on here when i think people truly have no idea.My "buddys quad" need this or "i ran 100oct" on 10;1 for peace of mine yadda yadda.Truth be told CAM overlap is gonna have a say in this.A big cam with more valve overlap is gonna let compression "bleed off" negating the need for race gas in some instances.I ran 93 pump in my yzf mx bike and it was 13.5;1 compression.It was liquid cooled though.thats the difference.I would hesitate to run 12;1 on pump in a air cooled motor with a hot cam.I would definately run a xtra oil cooler and bigger tank though to help cool.;) heat should be considered when build performance air cooled motors.If these 400s get too hot your power will drop considerably.;)

definitely something to consider...

My mod list will include:

Curtis Sparks foam air filter
40mm FCR carb with R&D power pump 2
Ported and polished head
Stage 2 Hotcam (for now)
JE 12:1 440 Piston on 110 octane
GT Thunder HD head studs
Cometic Gaskets
Curtis Sparks X6 big core exhaust
Oversized oil cooler with SPAL fan and stainless braided lines

Thoughts? I'm thinking it should be a reliable, powerful setup.

Furthermore, I think I'm going to just buy the piston, and cylinder separately...install the studs then take the cylinder and piston to a machine shop for a perfect fit.

[2muchquad]

I have the fcr and it really wakes up the 400.have the x6 exhaust and stg2 cam.uf build is similar to mine..:)

[CJM]

The major problem of the 440 is heat, it must be adequately cooled. This means larger oil tank, fan on the oil cooler or larger oil cooler and jetting must be right or on the richer side (too lean means too much heat). When you really get into it, unless you love the EX then a 450 might be abetter worthwhile investment in the end.

As for compression, the highest you can run reliably on 93 pump gas is 11:1. Anything higher and due to the nature of the aircooled engine you need to run 100.

[mattl31]

Originally posted by CJM
The major problem of the 440 is heat, it must be adequately cooled. This means larger oil tank, fan on the oil cooler or larger oil cooler and jetting must be right or on the richer side (too lean means too much heat). When you really get into it, unless you love the EX then a 450 might be abetter worthwhile investment in the end.

As for compression, the highest you can run reliably on 93 pump gas is 11:1. Anything higher and due to the nature of the aircooled engine you need to run 100.

While I do love my EX, I know a 450 would be a much better platform. However when you've dumped as much money as I have into this thing, you're kinda stuck with it. With selling a few of the parts im replacing, this build should cost me around 600 bucks, and thats not too bad to tide me over until I can buy another bike (ill never sell this one).

Plus, being different is fun :D

I've surprised some cocky 450 owners with my dinosaur 400ex as is, I cant imagine another point of compression and 40 cc's hurting me in that regard :blah:

[2muchquad]

yeah i have a yfz450 too but i like my 400.its actually a better mount for play riding in the woods.surely a 450 is faster mod for mod but i can embarass 450 riders on a mx track with my 400ex.Its all about the rider on a mx track:)