newb with questions

[vinnytobasco]

Hey everyone, I just wen't out yesterday and got my second 400ex.The first one i had i traded for a 1989 quadzilla 500 , and regreted it ever sence.Soo after not haveing a quad sence summer, I wen't out and got a 400ex yesterday, It is a 2002 and isen't in the best condition, plastic is a little ruff frame paint is chipped and rusted a little bit.It just needs a little love but i got it for $1100 so i'm very happy regardless.My question is my front brakes feel mushy I can pull the handle all the way to the grip, how can I fix that? I already have galifer brake rotors in the mail and steel braided lines comeing for the front.Also it seems that i have a tiny bit of play in the bars when i jiggle it, it ended up being a loose tierode end, but it still has a tiny bit and makes a loud noise if i turn agressivly.Thanks guys my name is vinny and i'm happy to be part of the forum!

[backwoods 400ex]

did you try bleading the brakes or check the brake pads?

[finsteratv]

glad to have another 400ex guy
sounds like you need to bleed your brakes and replace some tie rods. bring your questions here, this forum can be very helpful

[CJM]

Get a mity vac brake bleeder, I tried EVERYTHING to get the fronts bled and the only thing that gave me a solid lever was the brake vac bleeder.

And I second you probably need new tie rod ends.

[400man]

keep an eye out for a deal on some yfz450 front brake calipers.....they bolt strait up on the 400ex and are 10x better. if you can find some for 50-75$ on ebay then get em if you can...you wont regret it.

[vinnytobasco]

Went and worked on it , bled the brakes for the second time, I think i'l go for the vacume bleeder.If yfz450 calipers work, i can get a pair free off my dad thats sweet ! Just one tie rod end is bad it looks like.
But all that seems to be the least of my worrys :( . After further inspection it seemed that the head is leaking a tad bit of oil, after i looked closer it seems that one of the long 8 mm head bolts is stripped ( i don't know what the thread size is , but i used an 8 mm socket) I cleaned the threads of the bolt with no sucsess. Has heli coils ever worked well in this situation ? I have a giant tool box full of tools and not one tap long enuff to work.I'm stumped any help is much needed thanks !

[vinnytobasco]

Went and worked on it , bled the brakes for the second time, I think i'l go for the vacume bleeder.If yfz450 calipers work, i can get a pair free off my dad thats sweet ! Just one tie rod end is bad it looks like.
But all that seems to be the least of my worrys :( . After further inspection it seemed that the head is leaking a tad bit of oil, after i looked closer it seems that one of the long 8 mm head bolts is stripped ( i don't know what the thread size is , but i used an 8 mm socket) I cleaned the threads of the bolt with no sucsess. Has heli coils ever worked well in this situation ? I have a giant tool box full of tools and not one tap long enuff to work.I'm stumped any help is much needed thanks !

Also I want to do anything to prevent tearing into the motor, it was just rebuilt and i don't feel like screwin with the motor.

[CJM]

Helicoils work if done right. sucks it is crossthreaded. FYI those bolts get 7 foot pounds of torque when put on. I pretty much tighten them by hand these days for fear of stripping them.

[HondaPohl]

You will notice a big diff with the braided steel lines. YOur tie rod ends are most likey shot. I bought a vacuum pump from harbor frieght for 20 bucks and it work great. Good luck.

[hocman123]

i don't think anyone would have a tape that long. the really long bolts on the right side of the engine travel through the head and into the cylinder u could heil coil them just make sure u drill it all the way down the guy who did mine did and the bolt would bottom out and pull the coil out.

but in order to fix the bolts u need to take off the head

[vinnytobasco]

New tie rod ends are on there way.Ok now here is the big question, can I just leave it and fix it next time i rebuild it ? Could I just check for a head leak by spraying carb cleaner or wd40 on the head where it connects to the cylinder ?

[hocman123]

u could leave it but if it has a new rebuild on it, it would be a few years before u would need it again. i don't think spraying it would do anything to help u out i mean if it's lesking it's leaking u just need to look at it to tell.

now if it is leaking on the side with the long bolts behind were the header pipe runs thats not a huge deal u could just keep a eye on it. but i had a friend that had a real old bike that had a little leak like that and lent it to a friend told him to fill and watch it but he came back with a big *** hole in the side of the engine so if u forget just once or twice u could do damage to the engine.

if it was leaking from around the piston i would do that right away. For one just to see what the other guy did and 2 u will be lossing compression and it would effect the way it rides.

but ethor way u wouldn't have to take the cylinder off the engine so u wouldn't mess with the piston or the rings by fixing the leak and it's really easy to take the top end apart on this thing

[CJM]

The top end is 3 components:
1. The valve cover
2. The head (where the valves are)
3. The cylinder (where the piston is)

if Im reading your post right you said its leaking where the head meets the cylinder. This is a simple fix, remove 1 and 2 and helicoil the hole in the cylinder and then put all back together. if its leaking where #3 meets the bottom end your gonna have to fix it all and take it all apart. it isnt hard and you only need some basic hand tools-ask us anything aobut it and we can help ya too, this forum is great for that.

really, fix it-dont leave it alone. Chances are your losing compression-do a comp test. if its not at least 100 psi you need to fix it all.

and yea I lent my old pos suzuki to a buddy and yea they brought it back with the piston went thru the head and cylinder-nice big ol hole. I had been keeping up on the oil (it leaked from a few places) but I forgot a few times I had it out and thats what I got-a rolling hunk of useless metal.

Fix it right the first time, its cheap. Buy a new gasket set if you want or just the ones you need, do the helicoil and its fixed for less than 100 bucks.

[vinnytobasco]

I'm conviced, I will do it the right way haha after your guys experiences there is no question about it.I have takein apart multiple 2 strokes includeing splitting cases replaceing crank and bearings.It's just that 4 strokes freak me out, but I have to learn some how ! I just worry about putting it out of time and bending a valve or something :eek2: . My dad is a machanic, and I have tons of info at my disposal right here so i'm in good hands.

Any one got any good threads or help on with the timeing thing.Can i tear it apart without lineing up the timeing marks, and then put it in time once it is together I am confused :confused: .

[vinnytobasco]

Also it is the very long bolt by the front on the head pipe side yes.And your reading it correctly it is just leaking out of where the head connects to the jug.Oh another question how in the hell do you take off , remove , dismatle ???? the timeing chain ?!

[250rforlife]

you dont have to take it off. just catch it when u take the head off. and i suggest you get a repair manual. i highly sugest it! someone on this forum should scan the entire manual for use 400ex guys with our simple air cooled motors lol.

[vinnytobasco]

I will get a repair manual in the future as of now i just can't wait for a book for me to take it apart apart haha, I'l just have my dad walk me through it.I have to have my quad ready to ride by the weekend soo i got to get on it ! I will keep you guys posted, i would put up some pictures but there isen't much to looks at.

[tri5ron]

Originally posted by vinnytobasco
I will get a repair manual in the future as of now i just can't wait for a book.
I have to have my quad ready to ride by the weekend....

Why do I get the strange feeling we will soon be hearing something like,...

"Help !, How do I fix a stripped out or broken off bolt?"

Vinny,
I highly suggest you get the manual BEFORE you tear into your quad.
Ask your dad for his opinion on this. If he is a good mechanic, He will advise you that Patience will get you alot further, (and alot cheaper), than getting in a rush, and doing a half-azzed job.

There will be plenty of more weekends to RIDE, on a properly built machine.
But,
A machine that has been just thrown together, without the proper information and care, will certainly spend many MORE weekends, being WORKED ON rather than being RIDDEN.

Do it right, or don't do it at all.
It's usually alot more expensive to fix it the second time around.

[CJM]

just google "400ex manual" and you will find one online for free

[vinnytobasco]

Alright I will go that rout and look for an online manual, I don't wanna half *** it for sure!

[CJM]

its not really hard, most important tools you will need are a torque wrench thats capable of 7 foot pounds and one that will do 33 foot pounds. Its VERY important to torque the topend properly, specially the head studs and the valve cover bolts.

Just fire away if you have any questions.

[vinnytobasco]

Thanks cjm sounds good.And tools are the least of my worrys we have more tools than i will ever even use.I'm sure i'l be one here asking for help i appreciate it guys !

Also with the stripped head bolt hole,my dad took the bolt to his shop, and is going to lengthen it, he thinks there is quite a bit more thread left in the cylinder so we will see how that works out.He's trying to avoid haveing me tear into it because he knows he will be doin the motor work and i will end up just watching cause i'm afraid of 4 strokes.

[CJM]

I doubt your gonna get anywhere cutting more threads. The bolts dont reall strip so much as the sot aluminum the topend is made of.

As for working on them: Really its easy, manual has step by step and even then its so simple its not even funny. Course Ive had the topend apart at least a dozen times now on various EX's.

[vinnytobasco]

My dad extended the bolt by cutting aonther bolt of the same side welding it on to it, grinding off the threads, and it was lengthened about a quarter inch.I then cut of about a 16th of an inch, cleaned up the threads with a die, then put a little lock tight on it and torched it down to 7 ft. pounds :D . Then I ripped it around the neighbor hood, did a few wheelies, drifted in my snowy yard and called it a night. Man this thing pulls hard wheelies on pavment 1st through 4th , there is no way the motor is stock, all i see is a hmf pipe ? Also it idles a little high once it's warmed up, would that mean the jetting is lean ?

[CJM]

Very glad to hear it worked out for ya, 9x out of 10 it doesnt I guess you got lucky :)

Might have a stage 1 cam in it, thats possible. But you gotta remember these 400ex's are very light up front and wheelie super easy.

Idling high might just need to turn the idle down a bit. Theres a screw right smack dab on the left side of the carb you turn down or up to adjust. Only mess with it when its warm tho, easier to get it right. I have mine specially set so I can feather the clutch out in first and just let it idle along-just dont fall off it will run away lol.

[vinnytobasco]

One quick question, is the top end ticking noise a common thing with 400ex's? My old one did it and my buddys old one did it, why?

[CJM]

just the nature of the best. they all do it to one degree or another, never seen one that didnt. its the way the cams are and the way the valves are setup.

would be a good idea to adjust your valves too btw.