Friends 400ex making noise in the head.

[z400ACDC]

OK, friend came up with a his ex and wanted me to adjust the valves. He said it had about 10 hours on it since a rebuild with fresh bore. The valves did not need adjustment. I check the cam chain tensioner, it's ok. When I fired it up, it has a pecking sound in the head. it comes and goes. He said he thought the guy that built it left out the compression release. Any ideas on what I should look at?

[QuAdBoY4EvEr]

let me know when you find out what this is because mine is doing the exact same thing. just bought it, guy said valves need to be adjusted, i check the valves for clearance, they were spot-on. theres about 15hrs on this motor. JE 10.8:1 comp. piston 416bore. and stage 1 hotcam. it runs pretty good but im not liking the noise im hearing, sounds like the cam could be walking around, it comes an goes mostly at a high rpm though. just like a rattling, pecking tapping sound hard to explain but its pretty damn loud, can easily be heard over exhaust

[Ex'r Marlin]

I hope this helps, but I believe it maybe normal.

I too have a 10.8 to 1 JE 416 kit with a stage 2 Hotcam.

It definitely has a more noticeable "tapping" noise than when it was stock.

I have had the 416 done a few years now... Still running strong!:macho :)

One suggestion though... Check the tightness of the header to the engine. If there is a leak at this point, it will make a noise that sounds like the valves are in desperate need of adjustment, but actually, the nuts need to be tightened down on the header to eliminate the leak. After I had my header Jet Hot coated and installed the header back on, I thought I was in desperate need of a valve adjustment. Checked the valves... Right on. Checked the nuts on the header... Not tight. Tightened them down... All is well since.

Also, in colder weather at start up, the tapping maybe even more noticeable, but normal because of the lack of oil at the valves during start up.

Good luck!:)

[m1ke]

Possibly the timing off and valve tapping head of piston slightly??? loose valve guide? bent valve? i got no ideas... lol

[z400ACDC]

It sounds like it is coming from the head. The valves are ok. The way it comes and goes makes me think it may be from the compression release.

[chevyman440]

Use the old mechanics trick... get a few feet of garden hose with no ends on it...Put one end to your ear and the other to various parts of the engine. It'll be very apparent when you find it. Check around the exhaust and spark plug areas for leaks...they'll be extra loud. At least it'll get you closer to knowing where it is!

-Matt

[m1ke]

So remove/replace it. :)