February 25, 20179 yr I've just bought a brand new Mikuni VM 26 carb from the UK apparently jetted for my newly acquired '74 Cota 247. Problem is that the Cota needs some restoration 1st and the Mikuni will not be needed for a while yet. So I was thinking of trying it out on my Fantic 300 in the meantime which still runs the original Dellorto. My question to those in the know is, what Mikuni jetting should I install for the the '84 Fantic 300 just to get me going? I'm sure it will be different to the Cota 247 jetting. Edited February 25, 20179 yr by fourex Poor grammar.
July 22, 20179 yr Author I've not tried this Cota jetted Mikuni yet, I've since found the lightly stamped model # on the choke housing being 26A with 639 below. I've researched new Mikuni VM 26 carbs and found 5 different versions available being 606, 665, 8074, 8637, 8639, I'm assuming the one I have is the 8639. The inlet/outlet dimensions are all the same being 43/44mm and 35mm which match the Dellorto and the 606 & 665 being 84mm front to back whilst the others are 93mm (Dellorto is 90mm). Different configuration of air screw/idle screw/fuel inlet shouldn't really matter with the Fantic due to reasonable access from both sides. So my question to anyone that is running a Mikuni that runs well, is, can you tell me which of these models you have and what jetting works for you, please.
August 8, 20179 yr Author Just in case someone is following my previous rantings, I have more to add! It turns out the Australian distributor for Mikuni has a jetting kit listed for a "Fantee 250" (typo I hope) being for the VM26-8074. Needless to say I have bought both the Carb and kit in question and will fit it this weekend and hope for the best. I'll list below what jets the VM26-8074 has fitted as standard and in bold is the Fantee 250 recommended jets that I have available to fit. If anyone see's any obvious problem with this jetting, please let me know before I ride it this weekend. It's winter here in Oz, but it's still 20+ degrees Celsius during the day where I live, it's hard to take! We are also only about 30 metres above sea level. Cheers in advance for any guidance. Pilot = 60.(42.5). Needle = 5F3. (5DP39). Needle Jet = N-8. (O-2). Main = 180. (125, 130, 135). Air Jet = 0.5. Slide Cutaway = 2.0. Needle Valve = 2.5.
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