AJS & Matchless Owners Club

Greetings All,

Matchless 500 single, engine oil change after about 1000 miles and before the winter hibernation, some bronze particles visible in the used engine oil, some oil smoke from the exhaust when idling, both before and after the oil change. I can't recall seeing bronze in the used engine oil during previous changes. I'm assuming it can only be bits of phosphor bronze bearing or valve guide.

Does bronze in the engine oil always mean approaching mechanical failure? Bike generally starts and runs well

Does not sound good. I would suspect wear in the gudgeon pin bush or the timing side bush.

Couldn't agree more with Clive reference the timing side bush (although my gudgeon pin bush is white metal others aren't). My experience of bronze/brass in the engine oil was followed by substantial wear in the large timing side bush coupled with failure to scavenge the sump and consequent unpleasantness; plus costs. I would explore while it's winter.

Johnny B