Bent Valve?

[Choppers]

Alright well i have been fighting a problem for a while. I have repalced alot of stuff and now my dads friend has said it could be a bent valve or broken wrist pin.

Heres the problem. After 30-45 minutes the motor will get the clink clank noise when full throtle pressing. But it doesn't lose power or anything. I am just scared of something breaking and putting a whole in the motor. I really am about tired of this thing. I have sunk alot of money into it. I just wanna get to the bottom of this.

PS: I have put new cam chain, cam chain tensioner, head gasket. Its not overheating cause i installed a fan.

[jcs003]

get compression and leakdown test. this is a good place to start.

[Choppers]

ok. what should the compression run with the 416 11:1 ratio piston? do i need to do it after its warm ot does it really matter?

[jcs003]

Originally posted by Choppers
ok. what should the compression run with the 416 11:1 ratio piston? do i need to do it after its warm ot does it really matter?

Make sure the engine has been warmed up before beginning the test, to ensure that the oil has been warmed up. A cold engine will not test correctly.
Disable the ignition module or coil.
Insert the compression tester into one cylinder spark plug hole at a time.
Hold the throttle to full open position to ensure the engine gets adequate air intake.
Crank the engine continually for at least five to 10 full revolutions to obtain an accurate reading on the compression tester.

* i cannot tell you what the correct comp' reading would be based on knowing enging specifics, which vary.

[drew416ex]

Since it happens at full throttle, its possible you have a pulled head stud causeing exhaust to leak past the gasket or just a blown gasket. That will cause a bad noise.

[Choppers]

i put a new head gasket on and the head studs weren't pulled at all.

[drew416ex]

I had around 200-215psi compression when I had a 11:1 416 with a stage 2 cam.

[the Z Man]

Have you replaced the cam chain guides? they wear on the sides and rub the side of the head.....

[Choppers]

i think those are plastic. this is a a metal to metak sound.

[the Z Man]

Yes, and when the chain slides off the side of the plastic, it hits the side of the cylinder..
This happened to me/

[Choppers]

hmmm. great possibility. i am gonna let another mechanic ride it after it gets warm and see what he thinks. he told me off the bat what i decribed sounded like cam chain problem. which is what i think it is to.

[Choppers]

ok well i put all new timing in it. gears, slides, chain, tensioner. Still happeing. It has a new head gasket. It runs remarkable guys and no noise till it warms up and run it hard for 30 minutes. Then all hell breaks loose. Any more thoughts i just don't think its valves cause when i get it in neutral,1st,2nd,3rd it doesn't do it. just 4th and 5th.

[matt14c]

Did you check the studs for the cylinder? I had a bent valve and it wouldnt start or do anything so dont think it was that. I had to replace everything. All four valves, eight springs, and valve guides and seals. Maybe check something in the trans because if it only does it in certain gears then it should be something in the trans????? If it was a constance noise that was going on the whole time then I would think powertrain something.

[ae13291]

seems like its only doing it under heavy load. im really not sure what advice to give, as everybody already gave great info,

[Choppers]

yea only under heavy load. whats weird is if i shut it down and let it cool for say 30 minutes and start it up its fine then 10 minutes later since its already a little warm the noise is back. could it be spark knock? i run 93 octane.

[ae13291]

it could also be detonation for whatever reason, have you checked the spark plug? try maybe a lower octane, higher octane will make the motor run hotter, but you shouldent have a problem with that, its very weird man, check the plug tho, it could tell you something

[Choppers]

it looks perfect. but i swear it sounds like its around rockers or valves. its hard to hear and drive at 40-60mph.lol

[GPracer2500]

It's gotta be spark knock (aka detonation, engine knock, pinging, knocking). That fits perfectly with everything you've said.

Try some higher octane fuel and I bet the sound disappears.

[dariusld]

Sorry if I missed this, but whats your jetting, could it be lean, thus causing overheating:confused:

Originally posted by GPracer2500
It's gotta be spark knock (aka detonation, engine knock, pinging, knocking). That fits perfectly with everything you've said.

Try some higher octane fuel and I bet the sound disappears.

Listen to this guy. He's probably one of the most knowledgeable guys on here.

And I agree with him. The way you describe it, it sounds like it's detonation. That's very common with high-compression in certain areas and means you have to run higher octane fuel.

[dariusld]

Originally posted by DMC-4OOEX
Listen to this guy. He's probably one of the most knowledgeable guys on here.



Actually I'm thee most knowledgable guy on here and no one listens to me;)

Originally posted by dariusld
Actually I'm thee most knowledgable guy on here and no one listens to me;)

lol, I'm not saying you aren't smart, but I do know GPracer is super intelligent and almost always ends up being right lol

[Choppers]

i am running a 165 main with a 42 pilot with no air box lid and whats in my sig. i have replaced all timing gear and it was a waste of money basically becuase i replaced it once before thinknig it stretched somehow but it hadn't. I honestly think it is spark knock. cause if it was a bearing it would do it all the time. Would octane booster work or do i need to actually get 116 fuel?

[honda400ex2003]

I think that sounds a bit lean for florida but that is just me. I think it is getting warm and detonating. It would not run right at all if you had a bent valve. just my .02 though, steve

[GPracer2500]

You could try bumping the main up to maybe a 170 or 172 and see if that helps prevent the knocking. From your description, sounds like you're right on the edge (the wrong side) of pump gas being ok. The extra fuel might cool the combustion chamber just enough to allow you to run pump gas. I wouldn't count on it but you could try. If that works, just be aware you are right on the edge and you should be on the lookout for that tell-tail sound that signals deto is taking place. If you hear it, throttle back to avoid it.

I wouldn't bother with octane boosters. The common ones aren't worth a damn. The ones that work cost too much to be worth it unless better fuel is unobtainable.

I'd guess any fuel with a higher octane than pump gas would be good enough. You don't need "116" or whatever you're referring to. Any basic racing fuel (even an unleaded one) or even 100LL (aviation gasoline) would be fine, I'd bet. Remember to confirm your jetting any time you switch fuels.

[GPracer2500]

Originally posted by DMC-4OOEX
...almost always ends up being right lol

I appreciate the confidence. :)

But I can be wrong just like anyone else! :cool:

[Choppers]

i do have a 170 i will try it and get back to you tomorrow.

[dariusld]

What does Honda do when they rejet the new style carbs? I'm talking about the needle position. I know some people replace it with the older style needle that is adjustable.

Have you adjusted your needle? Do you have the DJ jet kit?

Originally posted by dariusld
What does Honda do when they rejet the new style carbs? I'm talking about the needle position. I know some people replace it with the older style needle that is adjustable.

Have you adjusted your needle? Do you have the DJ jet kit?

With the new carbs you have to buy little washers and "shim" the needle.

[Choppers]

No i didn't adjust the needle. C&D told me to just play with the jets he gave me. Whats the needle do?

[sab24711]

the needle adj is for 3/4 to wot moving it up leans it out and moving to down riches it up try that cause like you said its only at wot.
p.s if you have to move it to the bottom notch you need a bigger main jet. and its the same but backwards if its to the top notch.

Originally posted by sab24711
the needle adj is for 3/4 to wot moving it up leans it out and moving to down riches it up try that cause like you said its only at wot.
p.s if you have to move it to the bottom notch you need a bigger main jet. and its the same but backwards if its to the top notch.

False info.

The needle controls 1/4 - 3/4 throttle. Main jet controls 3/4 to WOT

[Choppers]

I have an 05 i can't adjust the needle can i?