Hello again, and thanks for bearing with me yet again!
I’ve got a 1975 Honda CB550 K1, and when the engine is running it sounds like one of the valves is making a ticking sound. Whether it’s a valve or not, it’s coming from the top of the engine around the cyl #1 location, which is why I think it’s a valve clearance issue, and it sounds like metal tapping against metal. It doesn’t go away when the engine is warm or cold, but it seems to smooth out when RPMs get higher than about 3500-4000?
It’s not terribly loud, but it’s loud enough to concern me and my paranoid brain. I can’t exactly demonstrate, but I’d say it’s about as loud as if I were tapping a brass key (like a mailbox key) against the top of the engine while holding it firmly in my hand. Again, each person probably is hearing a vastly different sound, but take it from me it’s about medium loud…….maybe a 3 or 5 on a scale of 10, with 10 being loud enough that you have no doubt that there’s something seriously wrong.
I’m just curious if it’s a big enough issue that I should refrain from riding until I have time to adjust the valve lash, or what. The bike runs fine and I’ve put about 250 miles on it (and God only knows how many miles have been put on it with that same sound coming from the engine before I bought the bike..)
Thanks for any help, hope I was descriptive enough.
EDIT: Is valve lash even what I am hearing here? I am not asking HOW to do valve lash adjustments (I already know that), I am really asking whether this sound I am hearing is a result of a bad valve adjustment in there, or if I even need to worry about it at all – maybe that ticking sound is inherant to these CB550 engines? I’ve never owned a bike like this and I don’t know what to expect, so that’s what I am trying to learn here.
Thanks so much!
My crystal ball isn’t working at the moment.
Sorry, I just had to say that.
Engine tear down and inspection is required.
It would’ve helped knowing the mileage on the engine.
A ticking noise is not normal, or common on that model.
It could be valve lash as you suspected – a simple adjustment can rule that problem out if the adjustment doesn’t make a difference.
If the valve lash isn’t the cause of the noise, the next possible reason would be a worn rocker arm and/or rocker arm shaft.
Rocker arms and shafts ware out on bikes all the time – your bike is no different.
The year of the bike helps in the rocker arm hypothesis.
Keep riding it, but take it easy.
Perform a major overhaul when the bike is not needed – like during the winter.
If the sound gets louder, or more pronounced – stop riding and fix it before any major damage occurs.
it is other possible problem is cam shaft joints where all the clamps that hold down the cam shaft. might be worn out. and it cause the cam shaft have excessive play that hit on top of cam shaft clamps. that sound like ticking or hitting sounds.
References :
It is possible that the valves need to be adjusted, but it is possible that what you are hearing is cam chain noise, which is common on that make and model of bike. I dont remember if there is a bolt to loosen the cam chain tensioner adjustment, but if there is, with the bike NOT running, back off on the bolt and lightly tap the tensioner housing with a light mallet as the tensioner may be stuck. If the valve adjustment and this doesn’t work, it is possible that you are looking at replacing the cam chain, as it is stretched beyond serviceability.
References :
My crystal ball isn’t working at the moment.
Sorry, I just had to say that.
Engine tear down and inspection is required.
It would’ve helped knowing the mileage on the engine.
A ticking noise is not normal, or common on that model.
It could be valve lash as you suspected – a simple adjustment can rule that problem out if the adjustment doesn’t make a difference.
If the valve lash isn’t the cause of the noise, the next possible reason would be a worn rocker arm and/or rocker arm shaft.
Rocker arms and shafts ware out on bikes all the time – your bike is no different.
The year of the bike helps in the rocker arm hypothesis.
Keep riding it, but take it easy.
Perform a major overhaul when the bike is not needed – like during the winter.
If the sound gets louder, or more pronounced – stop riding and fix it before any major damage occurs.
References :