0 intake valve clearance

[STinAZ]

So, just bought an 03 with 79k miles for $1,500. Has a nasty top end rattle, I figured either valves or camchain tensioner. All valves are almost in spec except 1 intake—0 clearance! I’ve seen this tons on dirtbikes, but not a Honda street motor. Maybe the last person screwed up the shim size (185)? Anyone else ever have 0 on an intake? I wonder if the seat is shot or the valve tuliped for some reason.

 

[dwalby]

All valves are almost in spec except 1 intake—0 clearance! I’ve seen this tons on dirtbikes, but not a Honda street motor. Maybe the last person screwed up the shim size (185)? Anyone else ever have 0 on an intake? I wonder if the seat is shot or the valve tuliped for some reason.

I had a FZR1000 that had a tight intake valve upon the first inspection, wouldn't fit a .002" feeler gauge so essentially zero clearance like yours. Took two tries to adjust it because of the original unknown clearance, but after that I put 118k miles on it and it was still running well when I donated it to charity.

 

[Kevcules]

There could be some valve train damage if the valves weren't checked or adjusted wrong in the past. I certainly wouldn't start the engine again until that valve was shimmed properly. Then you can listen for those terrible noises again. Good luck....

 

[sirbike]

No but I did buy an 18,000 mile 86 concours with three zero tolerance exhaust valves. Those cam lobes were polished all the way around. I set the proper clearances, did adjustments at scheduled times and it was fine. I discovered that the valves were tuliping, however, it never became a problem and that is not likely anyway.
My take is set the valve clearance and run it. If there is still a problem then it could be time to dig deeper.
If you have a compression tester, I’d suggest getting before and after readings.
I recently had a conversation with a former Honda tech about valves that leads me to say that if it runs fine after setting the clearance, run it kinda of hard a few times, that may clean up some build up and the valve will sit deeper, check the clearance again. And if you have a compression tester check that again.
I don’t know if a tight valve would cause a “nasty rattle”, however, it is a problem to eliminate

 

[STinAZ]

Somebody definitely had the valve covers off before, lots of sloppy gasket maker around the cam end seals. They also forgot to plug the crankcase breather back into the airbox, so it's gross under there now. Oh, they got every throttle body tube wrong as well in the air cleaner box. So my theory is they shimmed the valve the wrong way, would make sense with all the other mistakes. BTW I'm a bronze level Honda Mechanic, and saw 1 ST in the shop in 4 years I was there(tires). I plan on the compression test once I shim properly.

 

[RaYzerman]

What sirbike says...... I had an FJR with one valve at zero and it did take a little while to run better... but did eventually.

 

[STinAZ]

UPDATE: I found out why 0 valve clearance. One of the valve stem locks was loose and stuck at the top of the valve! I got it back in and seated, but who the heck knows how that came undone. Hopefully it stays put now.

 

[Larry Fine]

Nice save.