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Discussion Starter · #1 ·
The problem from my previous thread was migrating to a new problem and was not getting many views so I figured I'd start a new thread more specific to the problem. I need some help diagnosing my bike, I am trying to get it ready for the season and have been making some adjustments. It seems to be running really well, but it does not sound right. There are some noises that seem to be the loudest in the top end, I have adjusted the balancer chain, cam chain, torqued the head bolts and adjusted the valve clearance.

This was my first time adjusting the valves, so I am not 100% positive it is done right. With a cold engine, I adjusted the intake valves to .004 in. with a slight drag on the gauge, but when I rotate the flywheel to check the specs again, it always comes up loose and I'd have to readjust them again. It doesn't seem to stay constant and will vary each time it is rotated. I have to adjust it tight, so that after rotating the flywheel it will come up pretty close to the .004. The sounds might not even be the valves, but I am not sure what else it could be. I have some audio files that you guys can listen to that will hopefully help.

The first clip is with the mic pointing straight at the engine.
Sound clip 1

This clip is with the mic pointing away from the engine, there is a little more static, but a little less harsh sound.
Sound clip 2

Any input? Thanks!
 

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Discussion Starter · #2 ·
Ok, so I'm thinking it might not be the valves. I have now adjusted them about four times. (I know it really should not be this difficult. :) ) Anyway, two of the four times there was a distinct ticking noise, so I am putting the valves lower on the list of culprits.

The more I have been listening to it, the more it sounds kind of like a chain noise. As far as I know there are three chains in this engine right? Balancer chain, cam chain, and the oil pump chain. Both the balancer and cam chains have been adjusted, and the cam chain looked and felt nice and tight when I had the valve cover off. I am wondering about the oil pump chain though as it had about 1/4" of play.


One other thing I am wondering about is the forward cam chain guide. I can wiggle it around a little and am wondering if maybe it being loose is causing some noise.

What do you guys think, am I just being too paranoid? From the audio files, does it sound like something is wrong, or does it sound fine to you?
 

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I can't really comment on the noises, not sure what is acceptable or not, but on my CB400T the oil pump chain is the same as yours, very loose. Not sure if its causing or adding to the noise your hearing.

Did you adjust the cam chain tension with the bike warmed up and running?
 

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i just had my engine cover off to adjust my horribly knocking balancer and noticed that my oil pump chain is also a little loose, it should not be an issue though as the oil pump is not connected to any other component so a little slack will not make excess noise. as long as the oil is being fed to the valves then you are good to go.

also, it apparently is common to have to adjust the balancer chain again shortly after the initial adjustment as the chain is pron to stretch unevenly. a potato potato tech told me that and i was skeptical until my knocking returned after 20 miles, a quick adjustment through the access port on the right side cover quieted it right back down.
 

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This was my first time adjusting the valves, so I am not 100% positive it is done right. With a cold engine, I adjusted the intake valves to .004 in. with a slight drag on the gauge, but when I rotate the flywheel to check the specs again, it always comes up loose and I'd have to readjust them again. It doesn't seem to stay constant and will vary each time it is rotated. I have to adjust it tight, so that after rotating the flywheel it will come up pretty close to the .004. The sounds might not even be the valves, but I am not sure what else it could be. I have some audio files that you guys can listen to that will hopefully help.
When you turn the engine over after adjusting the valves you need to turn it TWO turns to get back to the same place . One revolution will place the cam followers on the lobes at tdc on the exhaust stroke.
 

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The picture in #2 is of the oil pump chain and a little slack like that is normal.
You need to re-read the manual on valve adjustment.
 
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