• @Airhead not too certain about precedents, but those articles previously about it said you can do it - the thing is even if 20 owners with old XJ600’s had the test, you still have to do it again for your own.

    That is, unless Yamaha can offer the information.

    All the same it would be quite easy to set the bike up to run lean enough to get through that test at the independent places. I believe those places are sympathetic to the cause.

    Currently the carbs are balanced and engine shimmed with performance in mind. My mechanic took extra extra care because he knows how much I love to get maximum out of the engine. It is likely running a bit fatter than you could get away with, because I have an overactive wrist.

  • I dunno how true this is, but I heard that leaner doesn’t necessarily mean less NOx. A richer burn means the unburnt fuel forms droplets or something.

    Anyway, have a picture of the Vespa I rebuilt during lockdown


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    • 9F6B1E43-EEEF-44A7-9068-CDDC9DCFA098.jpeg
    • 4875F0C6-019E-4208-A16A-A168A6F2EC36.jpeg
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