05-15-2026, 11:36 PM
I've just had a strange whistling noise coming from the fuel tank. I was concerned it was the fuel pump, but running the bike with the fuel cap open made the noise go away. My friendly neighbourhood mechanic reckoned it was likely a blockage in a tiny air vent in the filler cap and suggested I had a go at cleaning it up as the alternative would be to buy a new one. Of course, if one had an old bike like a 1969 Honda CB750, one could pull the thing apart, clean it up and even install a new gasket. Not any more. Honda would like you to replace the whole thing at a cost north of AU$100. I'm not confident that, if I got it apart, it would go back together.
Anyway, putting aside the grizzle, I took the cap off and cleaned it up as best I could, including giving it a bath in vinegar. I think I found the two little breather holes and scratched some crud out of them with a needle. I've run the bike for 10 minutes or so and the noise hasn't started again, so here's hoping.
However, I also noted that the spring which compresses to allow the lock tangs to spring out is working ok on one side but not the other. It makes it a bit hard to close the cap easily as the key does not simply spring back. Ideally one would pull it apart and clean the spring up, but I can't see how to do that and I'm not keen on breaking it.
Does anyone have any suggestions? Please?
Anyway, putting aside the grizzle, I took the cap off and cleaned it up as best I could, including giving it a bath in vinegar. I think I found the two little breather holes and scratched some crud out of them with a needle. I've run the bike for 10 minutes or so and the noise hasn't started again, so here's hoping.
However, I also noted that the spring which compresses to allow the lock tangs to spring out is working ok on one side but not the other. It makes it a bit hard to close the cap easily as the key does not simply spring back. Ideally one would pull it apart and clean the spring up, but I can't see how to do that and I'm not keen on breaking it.
Does anyone have any suggestions? Please?
Sometimes the road not travelled is best left that way. (Jane Goodall)