OP - sorry to step on your thread...

Posted by: @wobbly

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* To inspect a diaphragm you'll need to pull the slide out, then go around the rubber part stretching every segment to look for splits, tears and cracks, no matter how tiny. Diaphragm cracking is common on older bikes because the original diaphragm material (like that of the floats and float needles) was not rated for Ethanol fuel. It doesn't matter that all the internal parts "look new", if they are pre-Ethanol then they must be replaced. 

Remember: Your 1989 bike pre-dates the fuel change. So anyone working on an older vehicle has to have a "sense of history". There's a certain historical context that must be kept in mind when looking at these issues which demands more than a cursory glance. Each piece must get looked at under a microscope. 

Are there other parts in the carbs that would need to be swapped out for ethanol compatibility? I have a '75 R60/6 that I wasn't really prepared to rebuild the carbs on, but it came from Canada, and the PO suggested swapping fuel lines for ethanol (which I have done) but didn't mention carb rebuild...