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Engine design - is it an 'interference' or 'non-interference'

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Sprocket:
I'm going to go ahead and guess that as soon as you have a touch, the valve is bent and you'd notice the engine pretty much stop 'engining' fairly rapidly?

I have a tapping noise, once per revolution that sounds metallic.

I had trouble getting the exhaust gaskets in, and I can't be sure they're actually sealed properly (have ordered another set and will clean the area with a dremel to make sure new ones fit properly)

The bike starts and runs and revs absolutely fine. I was a little paranoid so last night checked the clearances again and they're all good. Also dipped a boroscope camera thing in there and couldn't see any evidence of any damage at all - so I can't imagine I'm in a situation where any of the valves has touched and I've not noticed.

Nurse Julie:
It could be an exhaust gasket leaking, someone else had an exact noise on a 550/4 and all was resolved when the header clamps were tightened. Another thing to check is the rocker arm spring positions. If the springs have been put in the incorrect sides of the rockers, the tappet clips the side of the valve stem top and not full face on and this also gives the noise you are experiencing.

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Rob62:
Too tight a tappet cleararnce can lead to touching the piston with the valve!..... doesn't leave much range for head and base gasket thickness variation then.. considering that the valve clearance is only 0.002"........

Nurse Julie:
Also, i wouldn't rule out a bent valve(s). If it were just a minor dink on to the piston, the engine would run with no noticeable problem at this stage but a few seconds of hard acceleration will burn one of the damaged valves and result in a leak.
Edit.....purely out of interest, what pistons have you fitted with the heart shape valve recesses?

Sprocket:

--- Quote from: Nurse Julie on August 20, 2019, 01:14:07 PM ---purely out of interest, what pistons have you fitted with the heart shape valve recesses?

--- End quote ---
Cruzinimage, exactly the same shape as the originals though - except the word 'Honda' wasn't cast into them!

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