1979 xs 650 Top end noise

[westonboege]

Hey guys, went on a 300+ mile ride on my bike a few weeks ago. Noticed some noise from the valves on my last stretch home. Motor hasnt had a valve adjustment in a few thousand miles so thats what i assumed it was.

Adjusted cam chain/valves etc. Cam chain was actually too tight... there was no movement on the adjuster pin. I adjusted it to spec, set the valves and went for a ride. Im getting the same noise still.

Rode the bike about 180-200 miles this past weekend and the noise is getting worse and worse. There is minimal tapping from the top end at idle... bike sounds great from idle up to about 3k rpm. Then from around 3-4.5k there is a nasty clanking metal on metal. It seems to go away once the rpm gets higher... but im talking 5th gear going 65-70.

It almost sounds like something is rattling like motor mounts are loose or something... check everything outside the engine and there is nothing loose that i can find. From what i can tell it is coming from inside the motor...

When i set the valves it seemed like the exhaust rocker arms had alot of side to side play. Is this normal? could my rockers be worn out?

Im gonna start pulling things apart tonight... recheck the cam chain and valves and make sure nothing is loosening up...

Cheers,

wes

 

[TwoManyXS1Bs]

Hey Weston, take your mechanic's stethoscope and probe around, especially on the two front tensioner bolts. Your rattle 'up from 3k rpm' sounds like front tensioner...

 

[westonboege]

Ill poke around on it... what do you mean by front tensioner bolts?

 

[mikem]

I think he means the 2 bolts that hold the front chain guide in place. They are behind the oil feed tube in the front middle of the cylinder.

I went and checked the a rocker cover I have, and the rockers only have a very slight side to side play... not sure if it would feel looser on the bike, but that may be a good place to start looking.

Not sure what ignition setup you have, but if you still have the advance rod and counterweights, I would take a look there, the assembly is affected by rpm and does have lots of parts that could come loose and make a racket.

Mike

 

[TwoJugs]

Hey guys, went on a 300+ mile ride on my bike a few weeks ago. Noticed some noise from the valves on my last stretch home. Motor hasnt had a valve adjustment in a few thousand miles so thats what i assumed it was.

Adjusted cam chain/valves etc. Cam chain was actually too tight... there was no movement on the adjuster pin. I adjusted it to spec, set the valves and went for a ride. Im getting the same noise still.

Rode the bike about 180-200 miles this past weekend and the noise is getting worse and worse. There is minimal tapping from the top end at idle... bike sounds great from idle up to about 3k rpm. Then from around 3-4.5k there is a nasty clanking metal on metal. It seems to go away once the rpm gets higher... but im talking 5th gear going 65-70.

It almost sounds like something is rattling like motor mounts are loose or something... check everything outside the engine and there is nothing loose that i can find. From what i can tell it is coming from inside the motor...

When i set the valves it seemed like the exhaust rocker arms had alot of side to side play. Is this normal? could my rockers be worn out?

Im gonna start pulling things apart tonight... recheck the cam chain and valves and make sure nothing is loosening up...

Cheers,

wes

Rockers should have micro play, while measuring them with a feeler gauge. Check your lash clearances. If they are in spec you might have other problems. When I adjust mine they motor is instantly quiet but it comes back to ticking after a few rides. Something I had to get use to with these bikes. Don't go too tight on lash. Lose is noisy but safer for the motor. Could be the chain adjuster as mentioned. Especially if the chain has gotten tighter since checked last?

 

[westonboege]

Well, i went back and readjusted the cam chain and set the valves again hoping that something was out of whack... Everything was withing spec.

I rode down from providence to Brooklyn this past weekend... about 450 miles round trip... If i keep the bike under 55 the noise is barely audible... above 55 and it instantly gets louder...

Took the oil filter and sump off when i got home and drained the oil...

Found a few small pieces of plastic in the filter on the side housing... and a little bit of aluminum... Im guessing that its the cam chain guide... maybe its just a little spot thats hitting aluminum? Thats why i only hear the noise above a certain rpm?

Anyways... pulling the motor tonight and ordering some bits... hopefully i pull it apart and thats def the problem... haha

thanks for the help guys... ill report back with findings...

 

[79Standard]

I too have a 79 XS650 and it's pretty noisy. Not sure is this is just the nature of the beast or what. I've been riding a Honda CB350f which is a pretty quiet and refined bike, maybe I'm just not used to it