400EX Problems...Newbie questions

[OverTheEdgeINC]

Okay. First off I went and traded my 99 YZ400 for a 2001 Honda 440EX. The guy told me the head gasket is junk. When I start it it just keeps turning over and shooting oil out between the head and engine case.

He said he forgot to torque the bolts so I tried to torque the bolts at 17lbs like he told me. So I did, The 1 will not tighten at all. Its the one at the rear of the head behind the rear 2 springs in the middle of them. I was trying to tighten that and noticed it won't tighten at all and now I am sitting here a total newb and un sure what to do.

Do I just find a stock head and put that back on? Do I look for a complete motor? I have a feeling the one on it is stripped. I traded for the quad hoping the headgasket wouldn't be a big problem. Anyways, Do you expirienced riders have any ideas on what I can do?

I have the stock head and piston here..


Thanks!

[redrock_tj]

is it leaking between the cylinder head and cylinder? or the cylinder and the engine case?
head comes off the top of the cylinder
and I just posted the Torque specs
hope this helps

[OverTheEdgeINC]

Heres a picture I just went and took to be more specific.

http://i373.photobucket.com/albums/oo176/BoneStockNeon/Photo-0108.jpg

[redrock_tj]

that would be between the cylinder head and the cylinder..
and if they won't tighten up the head studs have prob... pulled out. A machine shop is the answer.....those bolts should be more than 18 ftlbs......33

[tri5ron]

your saying it is a 440.
I'm assuming it's also a 11.5:1 or higher compression.
if that is the case, then in all probability, your studs are pulled out of the case, and you will need to have HD studs installed with Roll Form threads.
This is a common problem/failure on 400ex's, with high compression pistons.

If he just slapped in the high compression piston, and DID NOT go the extra mile by installing the HD studs, then you can bet that is the problem.

so in summary,... basically your screwed, until you get the HD studs.

[OverTheEdgeINC]

Okay I am totally new to this. How much do the HD studs run for price? Also how much would this cost at a machine shop to get fixed?

[redrock_tj]

http://www.gtthunder.com/TRX400EX.htm

[redrock_tj]

I paid like $55 for mine had to send them the cyl though....
install was about the same and if you don't have a fan on that thing to help keep it cool its time to think about it....

[OverTheEdgeINC]

If I just buy the studs could I have a local machine shop do the work for me? How long was the turn around time on your set? When it comes back I just install a new headgasket and assemble the bike again?

[bigbad400]

have a machine shop put them in it wont be any dif. than gtt will do themselves. just prolly alot cheaper to have your machine shop do it. then a new 89mm head gasket. and torque specs are 33ft lbs on the head studs. with hd studs torque values are the same from gt thunder.


i would have your valves lapped and readjusted too, just to ensure a good seat and you dont float your valves right into the motor. bean there done that.

[bigbad400]

and the piston too

[bigbad400]

id just buy a full topend gasket set and replace them all then you know that is shouldnt leak. you also want a stg 2 cam and a 450r carb. j/k but it makes a hell of a difference.

[OverTheEdgeINC]

I've decided its time for a rebuild. I found a Stage 2 cam, 450R carb, Yellow Plastics, CF hood, White Bros Pipe and couple other minor things.

On top of it all though, I found out my damn bike has a **** piston in it. It really urkes me when people have to lie about stuff. No doubt was the headgasket junk but the Piston has some nice Valve marks on top of it. There are nice score marks all around it. So, I am going to put my stock topend back on the motor and sell it. It will be a complete running motor then and I'll buy someones built motor on here. However I guess I got all winter to get this thing done...

Just a little mad I am going to sink more then I thought in a short period of time... Anyways... Just thought I'd update the thread

[jasonwayne222]

big bad what exactly happened to cause that. detonation?

[redrock_tj]

big bad what exactly happened to cause that. detonation? Yeah bro that looks like a TOP-Fuel grenade!!!

[TRXRacer1]

Originally posted by bigbad400

i would have your valves lapped and readjusted too, just to ensure a good seat and you dont float your valves right into the motor. bean there done that. IDK who told you that was from valve float but they didn't know what they were talking about.

[slightlybent47]

Looks to me like someone ran the fuel way to hot and had a melt down.