Star 90 Knocks

[DaveinWA]

I have a Star 90, 1976 I believe. It purrs when idling but when I get over 5 mph the motor knocks, bangs and makes a horrible racket. I've changed plugs and plug caps, replaced the carb jets and spark plug caps. Any ideas/theories on what is causing this?

 

[Oldsaltydog]

Re: Star 90 Knocks

Have you tried using a higher octane gasoline? Has the timing been checked lately? Is the racket coming from the cylinder head (see above) or from the lower end gearbox? If the latter, how is the oil level down there? Just a few ideas to start with.

 

[WhiteHorse]

Re: Star 90 Knocks

If it's "banging, knocking, slapping terribly", new spark lugs ain't gonna fix the problem. Unless there is some embellishment to the symptons, I'd say everyone already knows what time it is. Rebuild time.