BS34s and white plugs

Just gassed up madness, high compression 750 cammed, she's getting a bit tired, VM34 carbs, fairly high gearing, riding curvy state highways. Couple of hammer down runs to 75MPH or so, (testing purposes only;))
112 miles 2.2 gallons, yup 50MPG.
Only 14gal to Mountain View then:laugh2:
 
With jetting down the pilot air circuit and going up on the main jets…back from a sunny 1200 mile round trip to the beach with exactly 42 mpg
 
On either niche or jets are us, can you please post a link for the page with needle and needle jet? My needle jets on my bs34s, 1980, are out of round on the top. Or suggest what I may search for. I see in tech it's a y-o jet. I didn't have luck locating it. I would definitely prefer the genuine mechuni.
Thanks all.
 
I don't think originals are available any more so you'd have to get the re-pops. If I needed to replace some BS34 needles and needle jets, I think I would go with the "Canadian" ones. The needle (5IX11) has 5 clip slots so is adjustable, and there is a matching needle jet (336-Y-0) for it. This needle jet has more air bleed holes down the sides so is actually a little leaner than the original Y-0 needle jet. But, combined with the much richer 5IX11 needle, the result is still a richer midrange.

https://yamahaxs650.com/product-cat...arb-slide-needles-needle-jets-mixture-screws/
 
Not a WOT plug chop.
Typical part throttle lean emission plug. This happens on all lean setting part throttle and/or WOT emission carbs after time.
They always go leaner and leaner until no start.

cliff
 
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