Posted by Max Morley on September 04, 1999 at 06:57:49:
In Reply to: Valve Tap/ Noise posted by David Alcott on September 03, 1999 at 19:44:49:
Seem like all air cooled engines change noise as they warm up and the part heat and expand differently. Loud clacking is a concern, a slight tapping.clicking is usually OK. No noise or a sudden change to less noise would be a concern, tight valve clearnances cause burned valves and that get expensive.
The large solenoid is part of the compression release, ever wondered what the extra clack is upon cranking, it is the solenoid pulling in the cable to raise the exhaust valve slightly off its seat to lower the compression so the little starter and battery can do its duty. Some dirt bike singles have them incorporated into the foot crank or have a small level that needs to be pulled in before trying to kick start them. Max