help please

[Ruby Soho]

ok, so lately (past 2 weeks or so)ive been hearing a tick and you could only hear it on the left side of the engine. it only happened when you blip the throttle when warming up usually and then go away so i thought it was nothing. then after awile (different days) it was still there and i checked to see if it was a head gasket (no air coming out around topend, no leaks..that i saw) and i figuired it could be valves needing adjust meant, but what stumped me was how it would happen, and go away sometimes the whole ride, other times a few minutes or so. so today i decided to check it out and see whats wrong for sure. i let it warm up, it happened, i checked everything again, went down the driveway to the mail box and back up not blipping the throttle but slowly adding gas and it was fine, i dont loose any power or anything right, when i looked ONE more time, and right under where the carb attatches and the topend sits on the cylinder there was oil blurting out (not like tons but small bubbles). whats this mean? leaking gasket? blown gasket?

when my dad gets home im going to enlighten him on this wonderfull news:rolleyes: and probly take it apart tonight or tommorow.

now, i have a moose gasket on there now, ive heard cosmetic is really good so ill try them next. but i dont have HD studs. would installing these prevent this from happening ever again? also i bought it with a stage 3 stroker cam, and its only a 406. that doesnt seem to right to me so could this be part of the problem? would downsizing to a stage 2 help?

[Ruby Soho]

bump

[Ruby Soho]

bump again, this time i have a few questions i need answered.

i havent taken the engine apart yet, but last time this happened the stud nut wasnt tightened and that caused the head gasket to blow. this time its in a different place, so i dont know whats happening yet.

what is so special about the HD studs? why do they help so much? will they help prevent this from happening more? am i supposed to use something on the nuts like lock tight or something?

cosmetic seems to be the way to go for gaskets, or so ive read here numerous times. any suggestions there?

[GPracer2500]

If your head studs are coming un-torqued and allowing the head gasket to give way, then yes--HD studs should solve that.

The reason this is a problem with the 400EX is because the head studs don't go through the cylinder and into the crankcase like many (most?) other designs. The 400ex head studs thread directly into the cylinder. Then the cylinder has it's own seperate bolts that hold it to the crankcase.

This works fine for a stock compression engine. But when you up the compression from stock the threads in the cylinder can start to give way. HD studs are thicker and stronger but it's their heavier guage threads that really make the difference.

IMPORTANT: Much of the added strength from HD studs comes from the new threads in the cylinder. It is important to use a roll form tap (not a cutting tap) when making the new threads. Roll formed threads are stronger. Don't assume the machine shop that installs your new HD studs knows to use a roll form tap--tell them!

[Ruby Soho]

thanks gpracer, any suggestions on good gasket's? i had moose this time, they seemed to work well, but im going to try something different this time arond

[Ruby Soho]

once again, another question..

how do i figure out my compression?:(

[GPracer2500]

Static compression is a calculated figure determined by the manufacture of the piston. It's expressed as a ratio, e.g. 10.0:1, 10.5:1, 12.0:1, etc.

Dynamic compression (or cranking compression) is a measured figure that is expressed in pounds per square inch (PSI). This is measured by hooking up a compression tester to the engine. A comp tester is little more than a pressure guage that screws into the spark plug hole.

Dynamic compression is a far more valuable thing to know vs. static compression. It's more meaningful because it takes into account the timing of valve events, the quality of combustion chamber sealing, and even your elevation (5000ft swings are the equivelent of aproximately 1.0 static compression points). Dynamic comp tells you how much compression the engine is actually generating. Static compression can't tell you that.

To perform a compression test:
1) Warm up the engine to operating temp.
2) Remove the plug and hook up the tester.
3) Hold the throttle wide open.
4) Crank the engine over until the gauge stops climbing.

Warming up the engine is not absolutely necessary, but the measured figures will be lower on a cold engine.

[WhtPrd09]

go with stock honda gaskets.

[Ruby Soho]

thanks gpracer, your very helpful:)
when i bought my 400ex the person said that i should run 93 with some boost.. that means its probably atleast 11:1 right?


now, if i come to find out the gasket isnt blown because of a stud, and i know i can manage to keep stock ones (people with 406's dont use them..i think i could live wihtout) what is there i can do to to keep the gaskets from blowing? would getting a quality gasket do the trick?

[underpowered]

get a metal gasket instead of a fiber one. cometic, or factory are both layered metal.

[Ruby Soho]

i found this for a gasket

http://www.chaparral-racing.com/Chaparral/dept.asp?dept%5Fid=3318&gift=False&0=dept%2Easp%2Cdept%5Fid%3D1671%26menu%5Fid%3D%26T ree%3D%2CATV%20Engine&1=dept%2Easp%2Cdept%5Fid%3D3317%26menu%5Fid%3D%26T ree%3D0%2CATV%20Gaskets&mscssid=CA4CA999E7C3424A9AB8AAD4EB838892

when you scroll down to 400ex it says fits xr400..that will work right?

and also, if my stud nut came loose once again, i had some suggestions of using something like lock tight. only problem i thought about that is if i ever have to take it back off i could ruin something in the process.. is there anything made special for it? maybe over torquing it alittle like some people do with their 440's?

[Ruby Soho]

bump