Topic: Primary drive chain noise, vibration... HELP

[dboblet]

OK, first time on the hiway today after resurection from the scrarp heap.  Original chain (near as I can figure) on a '78 CB750F SS.  But there is this 'rattle' ... no, it's more like a rubbing and vibration that comes and goes, comes and goes, comes and goes.  So, while going down a hill, I put her in neutral and turned off the engine.  Sound doesn't go away.  hmmm.... So I repeat the above but with my helmet off on a downhill side road and .... seems to be the drive chain from down near my left foot and comes and goes as the chain goes round.  Grrr... Check the tension and it's ok, check for stretch or tight spots and it seems ok... so what's there for it to rub on??? 
Help??

[scondon]

   How much tension equals OK?  The original chain is a heavy one and will cause this sound and vibration you speak of when worn, dry, rusted, rear wheel misaligned, worn sprockets. Etc........


     Clean the chain with kerosene, dry, then saturate with 90 weight oil. Let sit overnight and set tension to 3/4" travel measured from the middle of chain. Check for tight spots.  Sound still there? Replace the 30 year old chain and sprockets with new ones.

    I haven't seen many of these original '78 SuperSport chains, granted, but every one I've come across was in very sad shape. And they all made the sound yours does.

[MRieck]

   How much tension equals OK?  The original chain is a heavy one and will cause this sound and vibration you speak of when worn, dry, rusted, rear wheel misaligned, worn sprockets. Etc........


     Clean the chain with kerosene, dry, then saturate with 90 weight oil. Let sit overnight and set tension to 3/4" travel measured from the middle of chain. Check for tight spots.  Sound still there? Replace the 30 year old chain and sprockets with new ones.

    I haven't seen many of these original '78 SuperSport chains, granted, but every one I've come across was in very sad shape. And they all made the sound yours does.

It's 30 years old.....it's all done (both sprockets and chain). As Sean mentions....replace it with a 530 conversion. Just do it.....it will eliminate the problem you describe.

[Johnie]

When you check the chain tension be sure you do it a few times in different areas on the chain.  I mean check it, then rotate it a little and check it again, rotate it a little and check it again.  I had that noise a while back and the chain was going from to tight to to loose because some links were locked up.  As soon as I installed my new sprockets and O-ring chain it was fine and the noise was gone.  Good luck with yours...

[dboblet]

Not good news for me.  It's got about 3/4" free play (both directions) mid way between sprockets.  All links seem to move freely.  Chain is still within the wear guides on the adjusters for being 'ok'.  I haven't noted any tight spots.  Alignment... hmmm, maybe I should check that again.  It's hard to make out the tick marks on the chain sprocket side of the wheel... I could be off a bit.  Is there a more accurate way to set it??  I admit there was a lot of rust present before I cleaned and re-lubed it... so there may be rust on links I culdn't clean out around the o-rings.... even though all links seem to move freely.  I want to go for a longer ride but not sure I should before I do more here. 

How much should I expect to have to shell out for a new chain and sprockets?

[City Boy]

MRieck is quite correct.A 530 chain and sprockets is a wise choice.The chain strength today is so  far superior to those of the 70's that the use of a 630 is totally unnecessary.You will be pleasantly surprised at the reduced vibration and noise.    Rock On

[MRieck]

Not good news for me.  It's got about 3/4" free play (both directions) mid way between sprockets.  All links seem to move freely.  Chain is still within the wear guides on the adjusters for being 'ok'.  I haven't noted any tight spots.  Alignment... hmmm, maybe I should check that again.  It's hard to make out the tick marks on the chain sprocket side of the wheel... I could be off a bit.  Is there a more accurate way to set it??  I admit there was a lot of rust present before I cleaned and re-lubed it... so there may be rust on links I culdn't clean out around the o-rings.... even though all links seem to move freely.  I want to go for a longer ride but not sure I should before I do more here. 

How much should I expect to have to shell out for a new chain and sprockets?

The best way to check....for future reference...is to pull the chain off the middle of the rear sprocket. If you can lift it over .150 it's gone. As I said....get the conversion sprockets and chain. I'd use JT sprockets. What you will spend is most dependent on the chain. Don't cheap out as cheap chain won't last AND it will ruin the new sprockets. You'll spend about 175.00 for a decent chain with those sprockets. Maybe a bit more.

[dboblet]

sounds like the way to go then.  I see the Parts-N-More web site has chain and sprocket conversions.  My budget won't go that far right now, darn it.  But it's the next item on my budget list.  Maybe if I sell some of the other parts I've got on e-bay....

[dboblet]

I checked it a bit at a time with the wheel in different positions and... um... very tight in one position.... like a tight rope.  So I re-set the chain slop to minimum spec at the tightest point and checked the slop at the loosest point... still (barely) within spec.  Obviously I need a new chain but I took the bike out on the road to check it out and the noise is gone now.  I'll budget for a new chain in the future but for now... it runs pretty darned good for a bike of this age.  Thanks (once again) for  the help.

[mystic_1]

That tight spot is a Bad Thing just waiting to be born.

Replace that chain ASAP and try to keep the burnouts and wheelies to a minimum for the interim.

mystic_1

[MRieck]

That tight spot is a Bad Thing just waiting to be born.

Replace that chain ASAP and try to keep the burnouts and wheelies to a minimum for the interim.

mystic_1

Yes....it will hurt the output bearing. A lot.