I have a 250 et that needs some carb help..........
Anyone have one on the shelf? I had the carb rebuilt, but no change. Did Yamaha ever offer a swap from the Kienen to Mikuni that you can actually work on without changeing eight thousand gaskets?

You obviously know nothing about that brand of carb if you can't spell it right. Countless snowmobiles and motorcycles came equipped with Keihin carbs. So what exactly is wrong with yours?