cam chain noise?

[cmattina1]

This is my second engine in the same bike. So, it's a 75 engine in a 78 bike. I would not expect the engines to sound different... but on the new engine i am getting, what i think, is cam chain noise. I would describe it as a rubbing sound that you hear get more frequent as rpms go up until about 3000rpm then it seems to disapear (or get to tight to hear)... at idle you hear it about ever 1/4 - 1/2 second.

I have adjusted the chain multiple times now, along with the valves (.003 & .005 [spec is 002 and 004]) and they are both good. The sound doesn't seem to change. It made the sound since the first time i started it, and i changed the oil after 1000km: there was ZERO debris in the sump, and there was some metal in the small filter...

However, i should ask, if I adjust the tensioner, and don't adjust the valves, will i have a problem? - i just ask because i have tappet noise when the bike is cold, but it gets quieter as it warms up, which is why i think the valves are okay...

the bike seems to run great, starts strong, idles strong (after it warms up). I am usually at about 3.5-4rpms in 4th doing 50-60mph, and in 3.5rpm in 5th to do 60mph.

I'll get a recording when it stops raining.

 

[Chuck]

Great question, I would like to hear from the old timers (Experienced). Mine always make cam chain noise on start up for about 30 seconds then goes away. I assume its becuase oil pressure comes up. Aslo have noisey tappets. I understand this is normal on the xs650. I am running 15-40 diesel engin oil. I wonder if 20-50 oil would quiet it down.

 

[littlebill31]

There is a system, or "order" for adjusting a bike. First the cam chain, then valve lash, then timing, then carbs (if needed). Your cam chain tensioner, and this is a long debate, should be adjusted so the pin is flush, or flush with minor movement (1+/-mm) in and out of the adjuster. I don't always adjust cam chain and valve together all the time. I will add that I always adjsut one valve at a time. And when I get that one valve set I then rotate the engine back around to TDC and recheck that valve. It's usually off a little.
Since it seems to happen every 1/4 to 1/2 at idle, I wonder if the main link on the chain is biting the cam or crank sprocket.
How is the tension er itself? Is it an original guide? Black plastic in the oil when changed?

Tappets also get dimpled and can cause noise and poor adjustment over time.

 

[cmattina1]

little bill, i was thinking the same thing about one part of the chain hitting. is it possible to be a bearing making the noise?

 

[littlebill31]

I could possible be a bearing, but it's one of those times where you really need to pin-point the sound. The old use of a screw driver or stethoscope can be a serious plus to find it. By pin-pointing the noise you will remedy it quickly. I have a bad tachometer drive gear in an engine and at idle it sounds like the cam chain. So, try to get a really good idea of where it originates.

 

[engine22]

I adjusted my cam chain flush and when I turn the engine over it does move in and out a bit. I feel like I have heard more noise since I made the adjustment when I first start the bike, and it goes away after about 30 minutes. The manual claims that it should stay flush when you turn the engine over, so I would be interested to hear some of the debate regarding the adjustment.

I have found metal bits in my oil filter so I assume the cam chain adjuster is not in the greatest shape. Can the bike still be safely driven like this?

 

[weekendrider]

With the slack off the front side of the chain (by tensioning with a wrench) adjust the nut (10mm) till it is flush with the end of the plunger. When running the plunger will "bob" in and out about 1mm (I never was fast enough to measure exactly).

These are old school and you are going to hear some noise. Chances are no two clatter exactly the same, but they all do.

If you are finding metal bits are they steel or aluminum? Test with a magnate.

5twins found sometimes a slapping or clapping sound that goes away it a while to be the bottom of the guide is loose and will slap on start till oil works its way in between to cushion it.