Want to bring the 400ex a fresh engine

[DJack]

I am looking to bring new life to the engine. Mine is a 2000 and i am the third owner. It runs great but i want to fresh it up because I do not know how the past owners were with the quad. I do not want to go above stock. What all should I do to the engine to make it like new? I am thinking new seals, rings, and basic stuff like that. Do I need to put rings and seals on the existing piston, or should I put a new sleve/piston as well?What is the best route(other that timing key,mods,etc) that will renew the engine?
Thanks

I would if it were me bore it out to a 406 and use a 10:1 compression piston and then buy all new seals and such.

[DJack]

Yeah but I live in a small town not really sure what my resources are for boring, polish etc are!

i'm sure there is a machinist shop somewhere. if not i guess you could send it out to someone.

[DJack]

thanks....I will look into it.

[brian76708]

i can understand why you want to freshin it up but why fix it if its not broken especially with how much it cost to freshin it up right your going to want to completely redo your valves/gaskets while your in there you mide as well do a timing chain new piston rings ext. it adds up quick so id just leave it so when it does brake you have a excuse to build it.

PLUS its a 400ex its going to be a long time before something brakes

[DJack]

Thats make sense....I think I will just start with the mods as it is totaly stock, and not worry about it till that comes. Thanks

where abouts in CO are you?

[DJack]

Born and raised in Pueblo but I am in Trinidad as of now?You a former Coloradoan?

[EX LONERIDER]

agreed on the "do not open"

just pipe it, jet it, and do the ignition key. those will liven it up quite a bit...... you'll be surprised what these do "uncorked"

dont open her up unless you wanna go MAJOR power ups or terminal repair.

Originally posted by DJack
Born and raised in Pueblo but I am in Trinidad as of now?You a former Coloradoan?

no but I am going out there in january for 6 days to go boarding. if you want the best in the states you go west. Otherwise Canada, whistler blackcolmb is the best in the world.

[coryatver]

If you want to freshen it up you should at the minimum

1. clean head, new intake valves at least
2. bore cylinder to next bigger size at least
3. new piston and rings
4. by now your crank probley has less than 50% life left I would get it rebuilt while you have it apart. I would get a hotrods.
5. new timing chain

you do that stuff and you will be good to go for another 8 years. I don't agree with the people that say don't open its 8 years old and doing mods that put even more stress on a warn out motor your just asking for trouble he wants to freshen it up.

[DJack]

Originally posted by FoxHondaRider
no but I am going out there in january for 6 days to go boarding. if you want the best in the states you go west. Otherwise Canada, whistler blackcolmb is the best in the world.

Thats for sure!!