Cam Chain Tensioner

[xlr8]

Greetings,
My cam chain is rattling noticeably when idling under 1500 rpm. The tensioner screw is currently extended down toward the engine about 2/3 of the way.  A mechanic I spoke with claims that these bikes (mine is a 77K with 33K miles) just do this and it's not a problem per se.  

Here's my two-part question: at what point does the cam chain need to be replaced? Is this when the tensioner screw gets "reset" and is screwed  back into the tensioner mechanism, to be unscrewed over time as adjustments are required per Honda (in the original owner's manual which I have) about every 3K miles?

It is hard for me to believe that these bikes rattled like this when they came off the assembly line back in the day.  Do people tolerate this rattle because the solution (replacing the cam chain) requires that the engine be essentially disassembled and it's a big price to pay to have quiet idling at 900 rpm??

[Re-run]

Best thing to have done is to have replaced the chain when the head was being worked on.
If you can remove the valve cover to get see the chain, you can replace it then. Just hook the new chain to the old on and pull it through and then once through, disconnect the chains and then rivet the new chain and there you go. As long as you do not move things, you do not need to worry about timing but if you are not positive, mark things before doing the job and make sure things line back up.

Make sure you remove the tensioner before doing this.

HOWEVER, there is to be some rattle, air cooled engines and all designed in 1968 and all.
Remove your tensioner and clean it out. You will be removing the rod so careful as the spring will shoot the rod across your shop of you are not careful! Clean the gunk out and then put it back on.
Unscrew the bolt to allow the tension to adjust some. Now according to my HONDA (not clymer or haynes) shop manual, adjust the tension with the bike running. Earlier methods had you go to tdc and then back off about 15 degrees. Either is fine.

Now a question. Does the rattle disappear some when you pull in the clutch?

[xlr8]

Yes, some of the rattle is definitely coming from the clutch basket, however, unless there is some danger in idling at 1400, I will live with it for the time being.

Thank you for the details on how to replace the chain without major effort ... not sure this hobbyist is up to that task.  If doing this would *guarantee* the rattle goes away, then I would pursue it but I am hearing you (and others) say that some rattling is inevitable given the age/design of the bike.  Perhaps this is part of the charm of the vintage bike experience

Thanks for the quick response.

[brcree]

  Make sure your carbs. are in sync. Sounds strange but mine were way off and it was hard to keep an idle and it sounded bad!..(Rattling). It's  a start, this needs to be done anyway. Hope it helps.

[mikey440]

Hey re-run, My rattle goes away when i pull in the clutch, what do you recomend i do to fix this rattle,
 I would like the bike to be as quiet as possible at idle, rattles only on idle, turned up idle a bit but would like to address rattle problem, any advice is appreciated, thanks, mikey440

[Re-run]

There will always be a small rattle but usually a good carb sync takes away most of it. Also, if the cam chain is a little out of adjustment, a little extra noise occurs.
Another possibility could be if the valves are a little loose, they wil make a little more noise sometimes.