going from 45:1 to 32:1 doesn't make much of a difference in jetting. Maybe at most 1 jet size in difference (and most likely not).
The main difference that using 45:1 and not 32:1 is a reduction in the amount of oil to lubricate the engine. I would rather jump a jet size up, run higher amounts of oil. I may be running richer, but I know I will have a well lubricated engine, making for a longer lasting engine.
On my 2001 Honda RS250 I run at 24:1 every time I do a top end, I am amazed at how good the parts look.
Thanks,
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Charles Gallant