Hi Guys, Had a brand new US$6,000 1979 Brat (Japanese version with 25 watt headlights! as I live in Costa Rica and that is what is imported to there) and a few years ago traded it for an 87 Brat GL (what else?) after 30 years of faithful service. IMHE, the inability to get an idle around 800 rpm is due to AIR LEAKS here and there. In the case of the Hitachi original carb, it was the throttle shaft that had worn the accelerator plate and air was entering around the shaft... thus the idle screw adjustment had no effect as it is essentially an "air screw". While the Hitachi was off and being redone by my machinist... he put in bronze bearings on both sides and that sealed it well. I got an offer of a Nissan carb for a 1500 cc engine for $30 and it was "like new" so I had my mechanic adapt it... he said it was almost a "bolt on" and today, several years later, the Nissan carb is working very well... better pick up than the Hitachi (the two butterflys open together, not one after the other like the Hitachi), more economical and never a problem. So when you have an unadjustable idle, look for air leaks. I have read good things about the Webers, but they are expensive and a friend couldn't get his air cleaner to adapt and still close the hood. We have annual inspections and a non original air cleaner will have them snooping for illegal modifications... like a replacement carburator not of the same manufacture. The Suby air cleaner adapted well to the Nissan carb.
