Jet kits

Oprahands

XS650 Enthusiast
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Ive been trying to find a jet kit for my bar I carbs so i could try a bunch of different jets to get my bike running right. Its very rich at the moment and i dont want to pay 10 bucks for every single jet id like to test
 
Welcome! You'll find many posts on this, but most kits are generic and contain bits and pieces that don't work for the application listed. You can usually trust only the float bowl gasket and float valve assembly, and sometimes the float valve seat is hinky. Avoid Keyster, lots of Chiwanese junk in those kits. Individual bits of genuine Mikuni parts look like they'll cost more, but at the end of the day you'll save time and money with them. Click the Tech button and find the link to the XS650 USA carb guide; year-by-year carb identification and components are there, and you'll be able to identify the parts you need. My favorite source for Mikuni brass is Niche Cycle Supply.
 
You'll need to narrow down the carb set I.D. better than that. There were 4 different sets of BS38s used on the 650 during it's production and they were all jetted differently. You base your re-jetting on what was stock for the year of the carb set, not the year of the bike .....

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Thanks 5twins! The chart helps a lot. Been reading your stuff on here for a while now actually and it helps.
 
For the usual "pods and pipes" mods many of us do, some minor re-jetting may be required. But we're talking just some small size increases, like one up on the pilots and one or two up on the mains. The exception is the '76-'77 carb set with it's very small 122.5 main. The one size increase for the pilot will hold true but for the main you may need to go 3 or 4 up instead of just 1 or 2.
 
You'll need to narrow down the carb set I.D. better than that. There were 4 different sets of BS38s used on the 650 during it's production and they were all jetted differently. You base your re-jetting on what was stock for the year of the carb set, not the year of the bike .....
Is that the same for BS34s or are these basically the same through the years?
 
The BS34s were changed a little bit compared to the BS38s but they remain very similar. Jetting changes required for mods remain pretty much the same as well. On my '83, I have pods and quite open mufflers. I'm one up on the pilots, two up on the mains, and one down on the air jet. The air jet is another tuning "tool" for the idle circuit.

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