Sprocket, Chain and Center Distance

Hello,

I don't know your application, chain or sprocket type, etc, but my experience in medium-size servo drives has been that torque does not vary greatly with normal ranges of slackness unless you're running it backwards and really loose. However, it is normal to put a "droop" spec on such drives and to have a tensioner arrangement. Just how worn are these parts?

Looking at the profile of worn sprockets (running Reynolds type roller chain I assume) I'd say the torque could increase or decrease (by a pretty small amount) depending on whether this was step-up or step-down. The teeth wear so that the chain rides radially outward. Varying centre distance hasn't the slightest effect, unless you tension the chain massively trying to keep it lower on the teeth. It wouldn't have much of a life in that condition.

< if the there would be a drop in the amount of torque, if sprocket and chain wear out, provided the centre distance is increased to compensate the wear and maintaining the slackness>

No isthe answer.

<what are the other reasons for drop in torque, apart from piston/bore wear, clutch plates wear and the wheel condition.>

None other.

If all the things you mentioned are worn, there is a real good chance your wheel bearing are shot too. Also carburetors wear out/get dirty and need adjustment/cleaning. Both of these items can reduce effective torque at the rear wheel.