[TR] TR3A timing chain lower gear

[Art McEwen]

Randall wrote:
> Art,
>
> When it's assembled, the timing sprocket is clamped against the front crank
> journal by the pulley hub.  It has to be clamped tightly enough to resist
> any motion whatsoever (relative to the crank) or things will quickly fail.
>
> The crank in turn is located by the thrust washers and should have only a
> few .001" play.  You can insert/change shims if needed between the gear &
> crank journal, to align the timing sprockets.  Procedure is in the workshop
> manual.
>   
Yes parts manual shows 2 shims so I though maybe installing an extra 1 
or 2 might get the lower gear out of it's little wear channel without 
miss-aligning the timing chain too much.

I can feel a small amount of crank movement forward and back but it's 
not enough to see so I'm assuming it's within spec when things are 
buttoned back up.
> It does look like you have more rotational play between the sprocket and
> crank than I would expect ... Are you sure the key was installed and in good
> shape?  A new key certainly wouldn't hurt.
>   
Haven't taken it off yet, figured I'd ask the experts here first and 
order the parts while it's still in place so I don't have to tax my 
memory for as long during re-install.

As I don't see a split link to break the chain I'm assuming the cam gear 
comes off to remove the crank gear? (manual's not clear).

Oddly enough the alignment marks don't look aligned, not sure whether I 
should leave well enough alone or move the crank a tooth worth.

> There is a Loctite product for "restoring" circular fits
OK good to know, I'll look for something similar.
>   
>> But the sprocket will also move forward & 
>> back, when it does there's less side to side play like it's 
>> fallen into a groove when it's in it's normal position.
>>     
>
> I think what you are seeing is the chain becoming tighter, as the sprocket
> moves out of line.
>   
There may be some of that but there's a definite channel the gear falls 
into when the play increases.
> -- Randall  
>
>
>   
Thanks Randall!