My carbs have received the Sirius carb rebuild kits but are still less than crisp. They are early '82s, I guess. Why? Because I have the flapper door on the air box, which makes them later early '82 carbs, but the accelerator pump adjustment rod is not threaded and not adjustable, unlike the late carbs. Right now the carbs have been stripped and are being dipped in Gunk carb cleaner. Whether this will remove the casting sand in the air-idle circuit that was supposedly a Mikuni manufacturing defect causing the Vision stumble, I can't say. I'm hoping the carb kits and the cleaning will correct the carburetion because I don't know what else to do. Does anyone else?
Where did you hear the casting sand excuse? never heard that one before.
you can rebulid these things all day long, but it usually takes a dip or two to clear the passages.
Don't leave it in the dip more than a half hour or the throttle shaft seals will degrade...
Oh, everything plastic or rubber has been disassembled.
The casting sand explanation is in the XZ550 Vision Wikipedia article. Didn't you, Lucky, write that?
Nope, not me
i'd say don't believe everything you read online...
Besides, those passages are drilled, way after being cast. I doubt there would be much sand left to clog them up, but it could have happened to one person & became lore, or grunge accumulation was mistaken for sand (remember, they didn't come with fuel filters)
--Lucky
Yes, I would think a passage that fine would be drilled but if it's inaccessible from inside the throat...The lack of a fuel filter explains the grunge in the bowls. Why did Yamaha do that? No wonder these carbs had problems and a fussy reputation. I'm expecting the carbs at last to be tip-top and that this long-neglected Vision is going to be quite a bike.
I thought the rest of the article was well-written. Check it out.
Thanks, Lucky, for the blog. It's interesting.