03 400ex head gasket problem

[honda_fan06]

I am new to the website and to working on the fourwheeler scene but am a certified mechanic on automobiles.
ok i have a 2003 400ex. i have done some research on the headgasket and such and need a little help. i currently have a wiseco piston 86mm bore with a compression ratio of 11 to 1. i have one bolt heli-coiled in the front and have a cometic head gasket. it ran for about 5 minutes or so and i mashed the throttle and it made a loud pop, and killed out. So i tried to crank it again and it made this wierd hissing noise and blowing smoke out in between the head and jug. i have had this problem with the last 3 headgaskets and all are the same outcome they start leaking or blowing smoke and oil out. Could someone lend me a helping hand and explain what the problem may be.
the first gaskets i had were tusk 3 layer gaskets i thought that was the problem so i got a cometic and it did the same thing.
Also i have looked up the GT Thunder Head Studs but i cannot get these due to my bolt being helicoiled. i dont have a stud there anymore i have a bolt.
Can someone shed some light on this for me?
Thanks

I also have some running issue problems too but i address that after i get the head gasket problem fixed........

[CJM]

The helicoiled bolt is whats killing it more than likely. There is a reason on these machines they use studs. Your kinda between a rock and a hard place now since you have the helicoil. Suppose you could do a solid bushing insert like a time-sert tho.

That or the head and cylinder need to be decked as its warped.

What did you torque the nuts down to for the studs, should be 33 ft-lbs.

[honda_fan06]

Yea according to my torque wrench it was 33 ft lbs and wat are the odds of the them being warped? And would time-cert work where could I purchase them at?

[HondaPohl]

I agree with CJM. Take it to a machine shop and they can put it on a granite block or indicate it to see if its warped. Heat is a major killer. May have warped.

[duroc825]

Have you tried OEM gasket? I had mine go after rebuild with Cometic and replaced it with OEM XR400r gasket with no problems.
I did have one bolt not torqued correct though. Also read my links and stuff from this thread, very interesting.
http://www.exriders.com/vbb/showthread.php?s=&threadid=459025

[honda_fan06]

no i have not tried a OEM gasket yet, and thanks for the links i will be looking over those. Thanks ill be updating this thread as i go along....

[CJM]

Gotta go online to find a timesert and they arent cheap. Its a solid bushing insert that works wonders-but it can be costly like I said.

A machine shop can help by telling you if the head is warped and possibly repairing it.

[honda_fan06]

I just talked to a local dealership here and they said that the kit I have is notorious for blowing head gaskets. And it's hard to fix. Would I just be cheaper and safer to get a stock jug and stock piston and just do it that way? Or what do you guys think?

[hocman123]

i don't think your problem is with the wiseco piston they are a vary good brand and since it is only a 406 bore and people can bore this thing up to 440 which is a 88 mm bore and not have this issue i think ur problem is the bolt u are using.

the timeserts u could find at a local industrail warehouse like fastenal and i know one more but the name i can't remember but i know it starts with a G.

i would just get a new cylinder and swap ur sleeve out u can get one in need or a bore on ebay for around 50 bucks

[honda_fan06]

So basically it would be easier to getthe time certs not to buy a stock jug and a stock piston? I also need to know what kind of headgasket to use if and when I get the time certs. I like the cometic but are they trust worthy with the 406 kit? If not what do you recommend? And what size time cert kit do I get to fix the problem? And time cert has to be pressed in by a machine shop right? So I need to tear the whole top end down pull the jug, get new rings, a gasket kit and bolts? And now the time cert does it come with the studs and nuts I need?

[hocman123]

well i think it will be easy to buy a cheap used cylinder and swap the the sleeve that piston rides in for your sleeve and reuse the same piston but if u want to do the time certs thats cool

i have a friend that has a 416 11:1 piston with the cometic seals and has tons of hours on it with no issue yet.

the time cert doen't need to be done by a shop u can do it yourself u just need to be able to drill and tap the hole for the larger cert piece and then srew it in

this is a good discription of what needs to be done http://www.exriders.com/vbb/showthread.php?threadid=449533

as long as the hole for the heilcoil is not to big u should be able to do it.

u should have to change the rings just because u are taking the cylinder off so i would not get that. all u would need is a stock stud that u can order from sites like bikebandit.com

[honda_fan06]

Ok yea I cOmpletly understand and I'm going to do all the studs just so I don't take any chances and do you know what size to get for it or the part number? And how do I know if the whole is too big for the insert? Thanks for all the help guys! And one more thing they need to be head studs not just long bolts with threads on them just so I'm clear they need to have threads on both sides with a nut and washer on top, correct? And heli-coil isn't as good as the time cert I read your thread or the link and he is using heli-coil basically I'm just confused on which is better. Thanks

[CJM]

Follow the link Hocman posted, thats exactly what your going to have to do. About all I would change is to start with a smaller drill bit if need be to make sure you dont go off center.

A drill press with a good machinists vise or a REALLY steady hand and that jug secured well are what ya need.

Course, a whole new jug might only be 100 bucks and then pressing it and such whatever the machine shop charges.

Its going to be a very tedious and take your time kinda job.

[honda_fan06]

Ok should be same size and all correct? And I don't have anything note do anyone I know around me that can measure the depth of the whole does anyone know the depth......And I found this on eBay is this what your talking about

Item #: 300504271678

Thanks

[honda_fan06]

Also have some more issues I need help with too. Just letting you guys know since I already many people helping that know what they are talking about and don't want you too fade off after this conversation above.

[CJM]

Originally posted by honda_fan06
Ok should be same size and all correct? And I don't have anything note do anyone I know around me that can measure the depth of the whole does anyone know the depth......And I found this on eBay is this what your talking about

Item #: 300504271678

Thanks

What the timeserts doing (if Im reading your post right) is its like a helicoil but its much more solid. Drill it, tap it, insert it and then you can put your stud in and your good to go. Follow that thread posted to a T and you should be fine.

Ebay item 300504271678 you posted looks good, bit costly as you might be able to find everything under the ez lok brand at a fastenal store (or online from them or someone who deals with them). I suggested tim sert b/c Ive used them with great success in Ford engines that spit out plugs.

There are some notable differences between the ez lok kit and the time sert kit that may or may note matter:
1. The EZ Lok seems like it can be put it at any depth b/c you can screw it in with a screwdriver.
2. Time Sert kit you need the special driver tool and the top of the insert is flanged and you must use the cutter tool to cut back some of the hole for the flange.
3. Price.

I took the liberty of googling the ez lock kit, its MUCH cheaper even if you add in the tap and the bit. http://www.grainger.com/Grainger/self-locking-inserts/thread-insert/fasteners/e-z-lok/ecatalog/N-8o6Z1z0hj2cZ1z0mk2d

Gotta take your time with all of this and think it thru before you order the stuff cause depending on what size you tapped it for already it may not work. The exteral threads of the ez lok kit at least are M16 which is quite large.

Good luck, fire away with anything else you need to ask.

[honda_fan06]

Thanks for that information and taking time too look that up. Ez loc I will go with and I need to buy some thread locking compound like on the link y'all pasted up earlier, and my heli coiled hole is m10-1.25 is what I put in it? So I need to get the inserts for that size and then get the wait.... I may have the bit already well I guess I do if it's already that size so do you need a specialty thread insert tool for those you showed me or like you said just insert with a screwdriver?

Also does it matter if it's carbon steel or stainless I found the on there for like 16 bucks and didn't know if there was a difference.

Last little bit of this then I'll move on to the next.

[CJM]

The inserts look to be M16x2 OD (outside diameter-so says the website) which is about (to relate a number you can understand) 9/16 diameter.

Im not 100% sure if the kit comes with everything but grainger has everything you need under "optional accessories" if it doesnt.

The time sert kit came with everything for what its worth, Im just not sure how deep and where the threads are in the head and how cutting the part out for the tapered end would wind up.

You could call a machine shop and see what they say, you dont want to helicoil it-but they may offer the bushing insert too.

The ez lok ones insert with a screw driver.

[honda_fan06]

Ok got ya I'm going to get that and try those. Now let's move on...

I have a stock carb on it I think I got the 400 off a trade... So how do I tell if it has a stock jet in it and if it does do I need to mess with it? Reason why I ask is because I ha it running for a little bit and it would idle for a little bit and then just kill out with no warning. I took it off and cleaned it and it's still doing the same thing. So I cleaned it again and still is doing it. Do I have to mess with the jets on it to get it too run right? I was trying to avoid that as carbs are my worse subject. I have a k&n air filter on it and I have cleaned that also. Just wanting to know about that why it's killing out with no warning and under throttle it lags a little like it's not getting enough gas.

[honda_fan06]

And one more thing on the headbolts is that thread pattern the same as the stock headbolts?

[hocman123]

well if u had opened the bowl to clean it u would have seen the jets u just need to read the side of the jetts. the idle jet u need to unscrew in order to see what size it is. stock is 148 main 38 pilot.

it sounds like u have a few problems like u need to go up on both the pilot and the main

what other mods do u have?? after market pipe, high compression??

just putting a 406 piston in means that u need to go bigger. but i am not the best person to talk to on the subject :)

[honda_fan06]

Haha yea that's how I am.......
It's a wiseco piston 11-1 compression dome top
Part number 4628mo8600
Stock muffler and head pipe
No other mods
All stock other than that.

And any clue on the head bolt thread size. Sorry bout going off subject.

[hocman123]

well the kn air filter changes ur jetting 2 u get a lot better air flow with that filter

i know its a 10 mm but not sure of the pitch i would think it is a 1.0 but maybe u can order the right one ( there is differant lengths make sure u get the right one) and figure it out when u get it then order the other stuff it would take longer. but if it's not that much i could get one of each and call it a day

[honda_fan06]

Wow you totally lost me on what your talking about lol sorry but I told you carbs are my kryptonite lol


OK SORRY IM AN IDIOT THAT IS THE HEAD STUD SIZE VOT YA THANKS

[hocman123]

well the second part was about the stud size the stud is a 10 mm by 1.0 pitch i think but i am not sure

[honda_fan06]

Yea sorry bout that I got alot going through my head lol I got ya and who would know about the carb stuff do you have someone you could get to read my post and lend a helping hand?

[CJM]

Originally posted by honda_fan06
And one more thing on the headbolts is that thread pattern the same as the stock headbolts?

Thread pitch and pattern should be the same, just incase it isnt its M10x1.25, thats 10mm OD and 1.25 thread pitch.

Handy jetting info btw: http://www.exriders.com/vbb/showthread.php?s=&threadid=445695&highlight=jetting+placement

Id say start at 170 and keep going down till it runs well and the plug is the proper light tannish/brown color.

Give it some time and steve should show up, hes better at carbs than I am.

[honda_fan06]

Yea I hope he does show up lol I am a COMPLETE NEWB when it comes to that I have NO idea what to do or where to start even what you wrote is confusing me lol.
Where do you get jets at?

[CJM]

You have to take the carb off, then remove the bottom and its all inside there. Its kinda hard to explain, the manual shows oyu step by step.

I dont have a link handy, but if you search google for something like "honda 400ex service manual" you can often find the factory service manual to download. Read it a bit, explains in detail how to do alot of things and its worth your time.

[honda_fan06]

I have a clymere is that just as good and I just don't understand the sapping jets out when u buy them do you get a kit of them or what and where do I purchase them?

[hocman123]

u can get them at any dealler or online at jetrus.com i would get 155 160 165 170 main jet and a 40 and 42 pilot and u should get it close enough.

but if its that hard for u i wold just bring it someplce to get it done for u after u get everthing else working well

[CJM]

The clymers so so, really try and download one of the factory manuals online.

You can get your jets at the dealer or jetsrus http://www.jetsrus.com/a_jet_kit_atv/honda_400_TRX400EX_1999-2008.htm they sell an entire jet kit so you can figure out which jet to use.

[honda_fan06]

Ok I found where to buy at is here.....

http://jetsrus.com/a_jet_kit_atv/honda_400_TRX400EX_1999-2008.htm

Is this the kit I need?

[honda_fan06]

Ok that's what I'm going to buy I guess it's right and as far as putting the right ones in I need Steve's input right?
And that kit has everything I need right, like main jets and The pilots or do I need to buy those separate?

[CJM]

Thats the kit that should do it. Ill go find steve, he might be busy so give it a day or so.

[honda_fan06]

Ok and I need to buy pilots too right?

AND OVERALL THANKS TO EVERYONE WHO HAS HELPED I HAVE NO IDEA HOW I'LL BE ABLE TO REPAY Y'ALL EVER!!!!!!!!

[honda_fan06]

Tell you what I will wait on Steve to get caught up on this thread and see what he says I should get before I go spending a ton of money for no reason. Ok I will give him a little bit too see what he says. Thanks guys.:p

[honda400ex2003]

Originally posted by CJM
Thread pitch and pattern should be the same, just incase it isnt its M10x1.25, thats 10mm OD and 1.25 thread pitch.

Handy jetting info btw: http://www.exriders.com/vbb/showthread.php?s=&threadid=445695&highlight=jetting+placement

Id say start at 170 and keep going down till it runs well and the plug is the proper light tannish/brown color.

Give it some time and steve should show up, hes better at carbs than I am.

alright, my apologizes on not looking at this one recently. I figured it was all good and didnt follow it. i was also quite busy this week and today mainly with heading home for the weekend.


the jets r us kit would work fine for you with the jets you said you wanted to get. you shouldnt have to buy any extra main jets for what you need if you get the full kit. I would suggest not buying the 40 pilot either, that will save you some money. even if you are a bit rich with the 42 you can get it dialed in with the f/a screw.

i would say that either the 170 that cjm suggested or the 165 is where i would start. probably the 165 and you will end up at a 162 with a 42 pilot in there at around 2.5 turns out on the f/a screw. leave your needle alone and you should be good to go.

i hope i covered the jetting ok for you, i didnt read every post word for word. I skimmed the first couple of pages since i wasnt interested in the helicoil stuff. i wouldnt waste my time doing any sort of repairs on a cylinder. I would just find a replacement stock bore and have it honed then drop in some fresh rings and be on my way. i havent heard much good luck come from most DIY helicoils or any other method. the one that you guys were discussing sounds like your best bet though.

Also review the jetting placement thread and if you have any questions feel free to ask. that shows how to test each section of your jetting along with tuning your pilot circuit and f/a screw.

steve

[honda_fan06]

Ok I'll buy the kit and also the needle should be left alone for all I know, I have to say this stuff is mind blowing to me and I'm trying to learn this so bear with me.

Ok buy the kit start out with the 165 and the stock pilot is 42 right? Or did I misread that?

And as far as the cylinder some guys on here suggested I try that EZ LOC first that it might work I don't think I can quiet afford a cylinder right now so thought I would give it a shot.

And that page you were referring to The handy jetting is that the one CJM listed above? And I'm just so new to this I don't even know how to explain this stuff....

Ok but I will try to figure this out as I go along and no problem not readin the thread, hey you can read all of them....

And so buy the kit and the stock pilot jet that's in it is fine just leave it alone correct?

[honda400ex2003]

the stock pilot is a 38

the stock main is a 148

you will get the kit and get a 42 pilot from jets r us.

i agree on giving the ez loc a shot along with the other suggestions on the helicoil stuff.

correct on the link i was referring to, that is actually the one i put together for info on jetting.

i hope that clears it up without too much confusion on either end.

My suggestion, make a new topic or pm me so we can start fresh. this one is bogged down with other info in it that will make it even more confusing to try to dig through.

read over the jets r us FAQ sections along with my jetting thread and a couple of others in the stickies and you should be starting to get a better idea of jetting.

What we have to do is step back a bit and start with the basics instead of trying to jump in with both feet at the beginning. it is a puzzle, lets start with the edges and work our way in.

lol

steve

[honda_fan06]

Ok I'll tell you what I got some stuff I'm going to do first like tear the quad down and clean the frame and all do a battery relocation, etc..... And when I get to the jetting part I will contact you or start a new thread. And I will be looking over some of the things you and others have recommended on looking at and going over and then ask my questions when I get to that point.

Thanks for your help to everyone who contributed and who will to continue to help.

[honda400ex2003]

edit: sounds good on the new thread after you do the rest.

ALSO DO NOT BUY ANYTHING YET JETTING WISE please. I want to make sure you are understanding what i am talking about before we get into working on it. it will be better for you and me both.

i have fought battles like that where people start doing alot of stuff all at the same time and it can make the process that much worse for everyone involved in trying to get it running properly.

By monday you will be all set to buy your kit and pilot.

Do you have a dealer close that stocks jets? yamaha or honda?
steve

[honda_fan06]

Yea I have a Honda dealership bout 45 mins away but don't know if they stock jets or not

Also I'm going to take my time on this thread problem I have and get it right first.

And I will wait before I buy anything to do with jets that will be another project.

Do one thing at a time my dad always says so let's stick to that.

And yea the cheaper I come out the better so I want to make sure I get the right jets before I go on buying stuff right and left.

[honda400ex2003]

it sounds like you are on the right track. lol get the cylinder fixed first. that will be the hard part of the project and the most $$$. lol steve

[honda_fan06]

Yea I sure will and I'll pm you the link to the new thread I start will all my mods and information you may need then we will go from there