1972 CB450 ticking noise

W

wtskm

Active Member
It's been a while since I've popped by here. Too busy working and riding.

Yesterday on the way home from work my cb450 jumped into neutral out of 2nd gear (it's been doing that for years now so no big deal).

I dump her back into second nice and easy, opened up the throttle and then I get this ticking / rattling from the top end.
No loss of power just an annoying ticking. I just adjusted the cam chain and set the timing about 2 months ago. Did not adjust the valves.


Anyone have any thoughts. Trying to post a video

thanks
 
Ticking is usually from the valve train. A little bit of ticking on these older bikes is normal. If it’s getting louder your tappet clearance may have increased just from riding. I’d definitely start by adjust the tappets


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thanks will do. Is that something that would just happen out of the blue ?

Any short term damage riding the bike to where I need to get to ?
 
wtskm said:
thanks will do. Is that something that would just happen out of the blue ?

Any short term damage riding the bike to where I need to get to ?
Click to expand...

If the ticking is a valve hitting the top of piston. yes you could damage it by riding.
 
Sounds like a slightly bent valve. I would strongly recommend pulling the head off and seeing what's up.

Just to get an indication if that's the issue, you could do a leakdown test first and see if it leaks through a valve. Clearly something broke or was bent and it will get worse if you continue to ride it.

And if the motor has to come out to get the top end off, great time to open it up and fix the gear problem. By now it's most likely worn dogs plus a bent selector fork.
 
That doesn't sound too bad. Do a valve clearance adjustment.

It might be the cam chain making noise. Adjust the cam chain tension again. Sometimes the cam chain guides fail. of course the only way to really inspect them is to take the top end apart, which requires removing the engine from the bike.

The slipping out of second problem is likely a worn "Star" gear which can be replaced without splitting the cases. I had the same problem. See my thread here: http://www.dotheton.com/forum/index.php?topic=70951.30
 
Its usually really difficult to diagnose a problem like this judging by recorded audio, but that sounds significantly worse than a normal valvetrain ticking or even loose tappets.

I would still start with a tappet adjustment and see what happens. If it doesn't go away I'd be opening the top end to see whats going on.
 
I went through the motions. Cam chain, valve adjustment, timing and the ticking disappeared.
Also noticed a bunch of issue while doing so that I will address with new parts and some elbow grease.
Cam lobes look clean i did the adjustment to a tight 004 = a loose .003.

Not only has the noise gone away but my ass wants to fly out of my pants when I give her gas.

thanks again. Now if I could stop ripping through a battery every year or so.........
 
Glad to hear it. Maybe time to check into the charging system, upgrade R/R. Battery should last you 3-4 years.


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