Primary Chain Tension

Chains can have tight spots and sprockets can be out of round.A tight chain will pull the clutch over, feel rough,damage bearings, ruin gearchanging and may not dip in the oil.Gearboxes are pulled back by the rear drive very often so if you start off tight>>>>>>>.?

Would have thought that the answer, Robert, would be to eliminate one by one the possible causes of the intermnittent tightness. I think the old saying "two wrongs don't make a right" applies here. An over-slack primary chain woud bring it's own problems with wear of the rubber buffers and the two sprockets.

George

I have always tried to run on the loose side. I'm still using the orriginal 1960 sprockets which show no wear at all. I have replaced the rubbers once in 25years. I have never broken a primary chain.It works for me.The gearbox moved back once and a tight chain ruined a set of box bushes in no time.George Cohen is a clever chap and has lots of time on Nortons.Did your slack mag chain ruin the sprockets and those expensive to fix mag bearings?. Bit unlikely.

That's an awful lot of slack.In my assorted bikes, I set the primary chain tension whilst putting as much weight as I can (an oily boot) on the rear chain. This takes up any play in gearbox adjusters and slack bearings (not that there should be) so that there should be nochange in slackness (tension is the wrong description) under load. Slackness of 1/2 inch or so on the tightest part of the run works well for me. Much slacker and you lose a lot oftranmission smoothness, not to mention having a chain lashing around the chaincase.

How often do you check your chain when the motor is very,very hot? and the engine plates have expanded (burnt finger!), Its surprising how much things can change.Goerge does get them properly hot.I don't set them as slack as him,but equally I don't follow the book or ride like him.. If we always did as advised -- we would not have bought a rusty old Rudge!.