11-19-2014, 11:19 AM
(11-19-2014, 10:41 AM)rick1366_imp Wrote: hi. Just got a 1981 CB90. It has 10,000 miles.
starts and runs smooth, but it has like a ratteling noise. I believe is coming fom the valve cover. more noticiable at idle.
any suggestions?
Tip. I was told bike was stored fir the last 3 years.
Hi. I assume you meant to type CB900 not 90.? Usually on these Hondas the ratteling noise is the cam chain. It gets stretched and needs to be adjusted. On many Hondas there is an adjustment nut, but the good/bad news for you is on the 900 Custom, it's automatically adjusted.
Since the bike was stored for 3 years (if they admitted to 3, it's more likely it's really 8 or 10) I would get some Marvel Mystery Oil and add it to the crankcase and ride the bike a couple hundred miles then change the oil. (I hope you already changed the oil after you bought the bike) MMO will clean things up and it frees up parts that could be sticking. You also can add MMO to the gas tank to clean the upper engfine area.
If the noise persists, and it's the cam chain tensioner, it's a somewhat big job- on the 900 the engine needs to be removed from the frame. And parts could be several hundred dollars. Other Hondas you could just pull the heads while on the bike.