valve seals?

[lilredhonda79]

Could anyone tell me whats involved in changing the valve seals and if it is something tricky or not?

[honda400ex2003]

head has to come off, then the valves and hardware come out of the head and the seals are on the top of the guides.

with a proper spring compressor it is pretty easy, without one its not worth messing with. i tried without a compressor, getting the springs off is one thing, getting the shims and such back in without a compressor is another. i was defeated and had my machinist do it when i got took the rest in to get worked on.

overall it is pretty easy though,
steve

[lilredhonda79]

right now im not even sure if it is the seals ive been reading some posts and it sounds like it, is there any way to actually know if they are bad or going bad?

[honda400ex2003]

there are some signs that show it such as smoke on initial startup and under hard accelerations.

rings are a constant smoke instead of intermittent.

what are your symptoms that are causing thoughts of bad seals?

steve

[lilredhonda79]

well right now it smokes under hard accelerations only when its warmed up and burns oil slightly but idles fine and starts perfect just the smoke i was worried about

[HondaRacing83]

eh my seals might be going to. my dad was chillen out in the field and he noticed after i lipped out of the berm and got on it everytime it was smoking, hasnt done it starting up though, and i didnt notice it when i was riding today. so idk. carbon buildup again possibly?

[honda400ex2003]

imo they are starting to go but not real bad yet so you are def on the right track.

it will get worse and start doing it on startup after they start to get worse, mine did the same thing before i did them. it started off as just doing it when warm and really laying on it. I actually noticed it because i could smell a bit of oil when riding behind my machine on someone elses when we would switch.

steve

[HondaRacing83]

Originally posted by lilredhonda79
well right now it smokes under hard accelerations only when its warmed up and burns oil slightly but idles fine and starts perfect just the smoke i was worried about yeah prob the gaskets

[honda400ex2003]

lol they can get replaced when he tears it down to do the seals.

might even be worth doing a bit of clean up and some rings while the head is off of it. a hone and some 85.5mm rings would be good to get it back in good shape for a long time.

steve

[lilredhonda79]

thanks for the info steve ill have to look into it sometime

[honda400ex2003]

you can do a compression test and see how that looks before thinking about doing rings. if it is 125 or better then you are good. a leak down test might help diagnose the seals but if the valves themselves are still sealing ok it wont show any leaks.

usually leak downs are for bad gaskets, bad head studs, bad sealing valves, or a crack in the head that is causing it to leak.

steve

[lilredhonda79]

thanks ill give it a try

[honda400ex2003]

sounds good, have fun with it. do you have the seals already?

get a head gasket from honda or get a cometic metal base one and use that. the cometic paper style ones dont work well.

steve

[lilredhonda79]

no dont have anything yet, ill probably tear it apart when i get some free time

[honda400ex2003]

sounds like a nice machine! lets see some pics
steve

[lilredhonda79]

dont know if it will show a pic or not

[honda400ex2003]

nice machine man!

steve

[lilredhonda79]

thanks, i love it, just got it this spring pretty much as you see it wasnt hardley even rode much, ive probably rode it more than the guy before me came with good tread but i ride a road a bit to much to get to the trails so they wore down pretty quick.

[honda400ex2003]

it doesnt take long to wear down the stockers. lol

next upgrade 20x11" razrs for the back and 22x7 for the front in 4 ply. great tires that grip and wear nice.

steve

[lilredhonda79]

ya i could tell the first time i rode the roads that they where already starting to wear and ya new tires in the furture for sure.

[01boneless]

ya i need seals to check your local shop mine had them for a buck a piece!! a good way to tell is pull of your header and look around the ports if theres oil its seals mine was soaking in oil on the left port but dry on the right side lol

[lilredhonda79]

That's sounds like a good price lol ill have to check that as well thanks