406ex vs. 400ex

[ridehonda400ex]

Im buying a 2003 406ex this saturday. I wanna know how much of a difference there is between stock and this size. He said its bored .40 over. It also has an FMF powercore 4. How good are they?

[CJM]

It wont be much, remember its not that much over stock.

[hocman123]

well if it has a 11:1 piston in the bike it will have a lot more kick then a stock

[PaRedneckRiders]

There should be a noticeable difference but its not going to be a LOT.
If you would throw a stage one cam in it with 11:1 it would have good bottom end and still run good.
I had a stock bore 11:1
Stage one cam
P@P and a k@n filter and for what it was the thing ripped and had TONs of low end power

[ridehonda400ex]

He said he's not sure about that, and hes gunna look at the paper work if he can find it. Im sure its 10:1 at the least. How are the FMF powercore 4 pipes? Ive heard that FMF 4 stroke pipes suck, this true?

[400exrider707]

FMF has been around longer than almost any other pipe manufacturer. If they sucked, they wouldn't be here. I've used their pipes on a variety of quads, never had any issues.

compression is usually where you get your power, the bore itself not as much.

[dariusld]

Originally posted by 400exrider707


compression is usually where you get your power, the bore itself not as much.

X2

[ridehonda400ex]

Dayyumm guys! I rode my quad he other day and let me tell you, it pulls soooooooo much harder over stock!! Itll slide no problem at all and the front wheels are constantly coming up!! And i love the FMF pipe. Sounds soooo good!:devil: :devil: :devil:

[ridehonda400ex]

Dayyumm guys! I rode my quad he other day and let me tell you, it pulls soooooooo much harder over stock!! Itll slide no problem at all and the front wheels are constantly coming up!! And i love the FMF pipe. Sounds soooo good!:devil: :devil: :devil:

[BlasterEaten250]

I'm pretty sure the lowest compression you can get on an oversized piston is 10.1.

[sheweezy]

It has to be higher compression causing it to be that much quicker.... your barely over stock with a 406, and a slip on exhaust isn't going to give you ridiculous, can't hold on hp gains...you might also want to talk to the guy and see if your not already running an aftermarket cam ...need to know that when time to adjust your valves.....

[sheweezy]

also .40 over im pretty sure is 85.5 mm=402

[slightlybent47]

It shouldn’t run much better then stock.
Don’t confuse a louder pipe with more power. It sounds like whoever had it rebuilt maybe just needed a slight boring to get rid of some scaring on the cylinder walls and went with just that and rings in order to save money.

[foreman 450]

So you can run a 11:1 piston with a stage 1 hot cam????????

[ridehonda400ex]

When i bought the quad he said it had a stock cam but idk, i love this quad!

[CJM]

Originally posted by foreman 450
So you can run a 11:1 piston with a stage 1 hot cam????????

Sure, but it wont have alot of topend power.

[foreman 450]

Ok thanks CJM. I still have stock bore with stage 1 cam sparks key and hmf slip on carb jetted welds ground down on pipe and uni filter. Runs real good now was just trying to get a lil more power,but I dont realy want to give up the top end to. So thanks again for your input.

[2001400exrida]

Originally posted by CJM
Sure, but it wont have alot of topend power.

i'm running 11:1 426 stage 1 hotcam right now and i love it!