Mikuni carbs Z400

gavroyer wrote: I just replaced my worn out diaphragms with the ones from JBM. They work great and install pretty simply. Definitely recommend those over the cheap ones on eBay. One of my diaphragms was a cheap replacement from eBay and it didn't have the keyway that points forward like the factory one did. Also seems quite a bit stiffer. I could never get it to seat right in top of the carb either. The JBM diaphragms fit perfectly and require much less effort to get seated. They are also supposed to be more ethanol resistant too.