I just installed a new tach on my 1974 lark 50 <br />when i turn the key on the needle moves to 0 and when i start to crank the motor the needle moves to about 800 rpms but as soon as motor fires the tach jumps and floats between 2000 and 3000 rpm,but the motor is clearly at idle<br />When i start to move the warm up lever up the tach drops to 1000 rpms and then start to go up as the rpms come up.<br />I just installed a new rectifier and ther tach is set at 8 poles why would the tach float between 2000 and 3000 rpms at idle.
