Guys with 440's I need some input!

[bert400]

Im wanting to get some more power out of my 440 and make it a little stronger. I just rebuilt the motor last winter. Here's what is done to it so far:

- 440 Wesico big bore kit - 11:1
- Gt thunder HD head studs
- Hotcam Stage 2 cam
- 450R carb
- Sparks full system

This winter Im wanting to get the head port and polished, HD timing chain (probably CRF450 chain), kibblewhite tittanium valve spring kit, 8 plate clutch kit, spal fan, and possibly a bigger oil cooler. Thats all I can think of right now...

What do you guys think of those mods soon to come? Good? Bad? anything you would add or change/take away? I need some input! Also what do you guys have done on your 440?

Oh also I need some ideas of where to send my head for port and polish..I sent it to Trinity Racing for my bore job and they did awesome work, BUT they reemed me on price..told me a cost and at the end it was 3 times as much and I was never aware until I was billed for it :eek2:

[tayyo789]

the HD studs are an absolute necessity. at least they were for me. make sure you get a quality gasket kit as well. a lot of people experience head gasket problems with 440 kits

[wrekd]

Plans sound good to me. I'll be doing the same thing when I tear into my motor again. Im going with the +1mm Kibblewhites though. I'll be sending my head out to www.advmachining.com. He's only about an hour away from me, so I'm gonna give that place a shot.

Might wanna throw in a aftermarket air filter setup too.

I say, your wasting your money. 440 big bores just dont do much. 440 strokers run great! IMO the biggest just overbore you should go is 416, after that its almost like useless. Other than that I like the mods. Honestly though I think advancing the timing does more than adding compression. Everyone likes a different setup but for me that timing key was by far the biggest gain I had gotten. If it were me 10:1 piston and +6 timing advance. I wont be able to try that out since i'm selling the 400ex but i'm placing my bets on it will outrun a 400ex with a 11:1 compression ratio. Just my thoughts.

[sab24711]

cooling is everything get the aux oil cooler there are some good threads on here that talk about it. if your planning on keeping your quad witch it sounds like it the oil cooler will deff help in the long run. the +1 intake valves and head port should be good. i mean flewby is right but you already have your kit and looking to make it better, i say just stick with it. your on the right path stick with it even though other people may say different but to each his own. once you get your work done that you said you will have not only a fast but reliable quad and i think that is most important. all the speed in the world cant help when your broken down in the trail.

[bert400]

Thanks for some input guys. I still have a couple other things Im wanting to get too. I will probably go wit +1mm intake valves..i also will probably get some type of air filter setup..right now I just run a uni foam filter and no lid..

[Miami_Vice454]

why do you say over a 416 is useless, its not useless, it cuts down on reliability a little but i know lots of people who have 440 kits and have never broken down.

[sab24711]

^^^ thank you!!

[racing12]

Those headbolts from GT THunder will save you lots of time and money. Definately a good idea!!!

[TRXRacer1]

Originally posted by Miami_Vice454
why do you say over a 416 is useless, its not useless, it cuts down on reliability a little but i know lots of people who have 440 kits and have never broken down. X2, when done right they're plenty reliable with noticable power gains.

[MtnEX]

OK... so I gotta ask...

I get the idea some folks think a 416 stroked to 440 is far superior to a 440 big bore stock stroke?

[jasonwayne222]

well ya because the 416 has thicker cylinder walls and dissapates the heat much better. and the 440 big bore is known for blowing head gaskets,

and some think that since the 416 piston is lighter it revs faster but im not so sure,.

[TRXRacer1]

Originally posted by jasonwayne222
well ya because the 416 has thicker cylinder walls and dissapates the heat much better. and the 440 big bore is known for blowing head gaskets,

and some think that since the 416 piston is lighter it revs faster but im not so sure,. Secure the head studs properly and the head gasket problem goes bye bye. It's not dominantly 440's, any high comp - high pressure - high heat situation with this motor can cause this problem.

This motor already has a real long stroke for a performance motor. I'd take the 89mm bore and some weight removal off the crank assembly over 4 more mm of stroke.


Originally posted by bert400

What do you guys think of those mods soon to come? Good? Bad? anything you would add or change/take away? I need some input! Get the flywheel shaved. Helps a lot on rev'ing that bigger piston out.

[MtnEX]

Originally posted by TRXRacer1
Secure the head studs properly and the head gasket problem goes bye bye. It's not dominantly 440's, any high comp - high pressure - high heat situation with this motor can cause this problem.

This motor already has a real long stroke for a performance motor. I'd take the 89mm bore and some weight removal off the crank assembly over 4 more mm of stroke.

Get the flywheel shaved. Helps a lot on rev'ing that bigger piston out.

That's what I was wanting to think about the stroke... but I'm not real sharp on the subject.

The only benefit I could see from a longer stroke might be longer duration with cam profiles to match?.... But then again, displacement volume is displacement volume right?

Like I said... not real sharp on the subject...



As far as lightening the flywheel.... I understand that would certainly increase response time.

Does that take away from low end grunt? The only reason I ask is my dirt bike buddy once told me something about ADDING flywheel weights to his YZ450 two wheeler for more low end grunt... or I thought he did?

[TRXRacer1]

Originally posted by MtnEX

Does that take away from low end grunt? The only reason I ask is my dirt bike buddy once told me something about ADDING flywheel weights to his YZ450 two wheeler for more low end grunt... or I thought he did? A YZ450 is a modern tech engine built for speed and performance only. He probably did mention adding weight. Us on the other hand are using speed and perf tech that was basically developed around 1983. These machines of ours were intended for sport recreation and consequently leave a lot of room for modern thinking.

[MtnEX]

Originally posted by TRXRacer1
A YZ450 is a modern tech engine built for speed and performance only. He probably did mention adding weight. Us on the other hand are using speed and perf tech that was basically developed around 1983. These machines of ours were intended for sport recreation and consequently leave a lot of room for modern thinking.

Right.... we have a way longer stroke on these... and I imagine a much heavier flywheel.

Bottom line to me though, is I have both, and I'm an open minded guy. So I can see the good and bad in both disciplines.

I think this might be a good part in why the 400EX is so stout feeling off-idle... and as stall resistant as it is... and the 450's are not????

So can the 400EX be lightened up enough to feel snappier, without loosing electric start, and without becoming stall-happy?

[TRXRacer1]

Originally posted by MtnEX


So can the 400EX be lightened up enough to feel snappier, without loosing electric start, and without becoming stall-happy? Absolutely. You cold take up to 6oz off without worry.

[togup]

i loved my 440 no issues in 4 years but like anyone of the male species i could not leave it at that i had to stroke it port and polish stage 3 hot cam 450r carb xr450 timing chain CP 11.5 -1 piston

[bert400]

Where do you guys usually send your flywheel to get shaved? Or do most of you just do it yourself?

[TRXRacer1]

Originally posted by bert400
Where do you guys usually send your flywheel to get shaved? Or do most of you just do it yourself? I use a local machine shop and specify how the work gets done. Same shop that makes me custom adapters, head stud inserts and flycuts surfaces.

[F-16Guy]

It's funny that people are so convinced that a 440 is the Anti-Christ. A 440 sleeve gets installed just like a stock sleeve does, so if whoever installs it knows what they're doing, a new sleeve and a couple more millimeters of piston should be just as reliable as a 416.

If I were going to build a 440 on my budget, I would get:

PARTS:
-- Wiseco 89mm flat-top piston kit
-- Cometic MLS 89mm gasket set
-- HRC copy cam if available, or stage 2 HotCams
-- 450R cam chain
-- 450R carb w/ ZRpilot adaptor
-- HD clutch springs
-- FST style cooler
-- GT Thunder HD studs

SERVICES:
(GT Thunder) Install studs, sleeve, deck cylinder, fit piston
(??????) Clean-up port and valve job
(DIY) Cleaning, teardown, and reassembly
(DIY) Drill and tap fittings for cooler and fab grill