I'm still dialing in the new Mikuni VM26 on the 250. Long story short, it works best in the midrange with a 100 main and the needle in the middle. It has the best top speed with a 115 main. However, with the centered needle on the 115 main, it runs rich and bogs and sputters a certain spots on the mid-range. Right now I've got the needle on it's lowest setting with the 115, but I'm thinking there has to be a better needle profile for me. The current needle is a 5FL14. I see
lists needles for this carb. So which of the following would yield me fatter needle with less taper, thus leaning up the mid-range:
Actually, I think Jeff gives the Sudco tuning guide a bit more credit that it deserves. The numbers (badge numbers) on the jet needles are pretty hard to interpret but you will need to replace the jet needle you have with another "5" series jet needle. I suggest you give the 5DL31 a shot... this jet needle is a good compromise and was used on the 76 VM26 carbs for the KZ900 as well as many of the earlier VM24 carbs. I am not familar with ANY 5F... series jet needles but they would likely be pretty rich...
wiredgeorge Motorcycle Carburetors
Mico TX www.wgcarbs.com
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