rebuild

[realbeef]

Im going to be rebuilding here shortly havent picked any parts out yet but im open to all suggestions. I ride trails and where ever there is sand. I can spend roughly 800-1000 dollars on this motor I want as much power as i can get. Also running race gas doesnt matter to me I have a station that sells it right next to me. so im all ears lets hear it :D

[01boneless]

well if you want a realiable trail bike i would do a 416 witha 11:1 piston and a mild port and polish ,a hotcam stage 2 or 3, hd head studs, crf 450 cam chain and new guides and tentioner, and cometic gaskets, and oversized oil cooler and spal fan

[realbeef]

will that fit in the budget?

[01boneless]

shoul be just right if you want cheap go for a stock bore piston with 11:1 compression stage 2 cam groud header welds crf chain slipon uni filter jetted carb cometic gaskets youl have great power also you can do a sparks key but you will have to run race fuel un less you do 10:1 compression and that stuff should be about 500 bucks

[Speed37]

what is the purpose of a header grind?

[CJM]

Originally posted by Speed37
what is the purpose of a header grind?

Makes the exhaust flow more freely. If you look at the front of the header where it meets the head you will notice the welds there are quite thick and restrictive-grind it away a good bit and it flows better.

[Speed37]

really, i honeslty never woulda though about that. But CJM How does your outerwears lid sound on your 400? Cause i know on my blaster it gave it a deep tone to it, but does it make it sound deeper toned or what?

[CJM]

Kinda hard to tell since I have a slip with no spark arrestor in it as well tbh.

The lid def gives everything enough air to breath-Im willing to bet it also makes the exhaust deeper.

[Speed37]

any noticeable power gaiins?

[JamesPyles]

This crf 450 cam chain, which year 450 and for all years 400ex is this good to do too?

[ish416]

I would recommend an 04-05 450R carb or an FCR. One of the best bolt ons for the dollar. Especially on a modded engine.

I suggest a 416 11:1, Stg 2 Hotcam, Hd head studs, cometic gaskets and the 450R or FCR carb. Replacing the cam chain, guides and tensioner would also be recommended since you will already be in there.

An exhaust header may be noticeable but that should be one of the last mods to do. Grind down the stock header instead.

[realbeef]

right on how much power will that 416 build yield over stock?

[ish416]

An 11:1 416 with Stg 2 Hotcam, and a 450R carb with a good filter and slip on exhaust should put down somewhere around 34-36 HP, maybe a little more with headwork. Compare that to the stock 26.

It should be quite noticeable compared to a stock or piped/filter/jetted EX.

[realbeef]

well thats pretty impressive. I cant believe just how mild these motors are. just out of curiousity how much does a stock 450R make? and I cant afford it but what about a full blown 440 build? how much power will that create over stock?

[ish416]

A stock 450 of any brand is somewhere between 35 and 40. The Honda 450 is at the very bottom of the 450 class stock.
But with just an intake/exhaust/rejet or fuel controller they can gain an easy 8 HP or more. All of the 450s are pretty restricted from the factory.

A full build 440 depends on if its just a bore (89mm piston) or a bore and stroke (87mm piston and +4mm stroke) 440.

The 89mm 440 on a full race build is likely in the lower-mid 40s on HP. The bore and stroke 440 is probably 2 or 3 HP more.

A 440 (89mm bore) built identically to a 416 or 426 is only good for another 1 or 2 HP. Unless you do a bit of head work the 440s don't typically make much more power than a 416 or 426.

[realbeef]

thats good info man thanks.

[Johnb427]

I just got mine back together a few weeks ago and I am very happy with the 416 and 11:1 compression. I also have a stage 1 hot cam, slip on, open air box, hd head studs, and a spal fan and I am running vp 110. I have only rode it once since I bored it and up'd the compression but I could tell a huge difference in low end power.