Primary chain tension

Hi Chris I know what you mean. It is very easy to confuse the tightness by pushing down too hard and getting a larger movement. The slack is the easy free movement, "slop" if you like and it is the total for the up and down movement.

I always like to measure the chain slack by applying a load to the chain and removing any drop on the bottom run so all the free movement is up on the top run. This can be done by applying a light load on the kickstart while you test the free movement on the top run. You might find it easier if someone helps you with this but it can be done if you sit on the bike and lean down.

The pre loading the chain will also mostly remove any clutch slackness or wobble and you will get a better more accurate test more commensurate with the chain running under load.

There are two very important things that you should always do when you adjust the primary chain. First you must over tighten the chain and then you must move the adjusters to push forward the gearbox to a position that the chain has the correct amount of slack. Then, tighten slightly the main gearbox clamp nut and test over various rotations of the engine to get the tightest spot. This must be used for the test.

NEVER simply adjust backwards from with an over slack chain. You MUST ALWAYS go over the whole tightening and loosening cycle. IF you do not, the chain is guaranteed to pull back on the inherent adjuster slackness and result in a bar tight chain which can damage bearings or even snap the chain.

Just another tip: you can adjust the rear chain more accurately if you select a gear and turn the rear wheel backwards. This will put all the free movement at the bottom chain run where it is easy to test. Once again do several measurements after turning the chain to different positions. Quite often the specified measurement must be done with the bike loaded, so it is far better to get a normal weight person to sit on the bike and have them apply rearward pressure while you do the measuring.

Reagards

Les H

Sorry Trevor I have called you Chris. I have now made this mistake twice today! I have also called someone else Chris when his name was well know to me as Jim.

My apologies....doh!! Dead embarrassing!

Les