Out of Control Valve Train Noise

[layback209]

Well the hawk has been siting for a few weeks, decided to fire it up and hop on for a little cruz around town (was nice day about +6deg).

Anyway was cruzing around and all of a sudden the right side of the engines valve (clutch side) trian started making a horrible "rattleing" kinda noise.  now i know the 1984 cb650sc has hydrolic self ajusting valves so you should only here a nice friendly click if that. And it is not low on oil near the upper side of the Xs on the dip stick.

Anythoughts? as to the cause/sequence of stuff to start checking would be appreciated.

I was thing that the top right side of the engine wasn't getting any oil?  I was running 20w50 in it the oil was probably to viscis for the weather.  I supose the easiest thing would be to change to 10w40 and see if that works.  Mabey the oil pump is worn out (engine has 62xxxKms)? 

If i pop the valve cover off what should i be looking for? i would guess carbon deposits on the cams?

Cheers,

 

[Hondo]

I would first adjust the cam chain tensioner-

[detdrbuzzard]

sounds like a start hondo. how old is the oil or did it break down?. lifter collapsed?

[JordanA]

I have to agree with Hondo.  This sounds identical to my cam chain tensioner woes, but I have no clue how to go about fixing it.  I need a manual.  If it is simple enough, I'll attempt it without the manual but can find no online info or people willing to explain it.

good luck with the repair!

[detdrbuzzard]

i'm not sure if the tensioner just bolts to the back of the block on nighthawks

[JordanA]

From what I've read and understand to this point, I feel like you have to remove the valve cover, loosten some bolt, then just automatically re-tighten said bolt.  Then, reassemble and start motor, check for noise.  If no noise, success.  Noise, try again.

[layback209]

Sweet, thanks for the advice...

I'll look into tightening the cam chain tensioner.  Not %100 confident thats it though, i used to get an ocational rattle from the chain (very distinct noise), but i did some shifting at around 7g and that "fixed it" or somehow caused the tensioner to re-ajust.

Mabey the tensioner has loosend off, i'll try and rule out the tensioner then go from there.

sounds like a start hondo. how old is the oil or did it break down?. lifter collapsed?

The oil has about 3000kms on it, shouldn't have broken down yet, still a nice light brown color. 

I'll get to reviewing the Clymer manual and see what i can dig up.

[detdrbuzzard]

well i can tell you what happened on my '79 cb750k when the cam chain tensioner did not adjust. it sawed through the front of the block and thats how the 900f motor ended up in the bike