Hello hoping someone can help me out on here. I have triple mikunis that upon acceleration will not let my car go above 60mph and also has a lot of stuttering and misfiring. Now I'm thinking bad fuel among tuning of the carbs. The fuel in tank is a few months old. So any help will be greatly appreciated.

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You haven't given enough info for a proper answer.

What engine? Be specific about performance upgrades.

Ignition?

What's your jet settings?

Did this problem just happen recently?

Details are indeed necessary.

In general it sounds as if you are running very lean. This can be caused by many things however, such as too low fuel pressure, incorrect jetting, plugged fuel lines/filter or carb passages, or intake air leaks at the mating surfaces to the carbs or head. Old gas is not likely the cause, its not THAT old.

Start by telling us your running fuel pressure (stock mechanical or electric pump?) and your main, pilot and air corrector jet sizes and recent history. Also any other details of how its all installed. Are these new to you? Did it run fine for a while now its bad?

They are brand new NOS triples from wolf creek still were sealed from early 90s or so in original box. Ignition is the Kameari Unit, a BSR/FAR cam, mild port heads, Clifford headers, 2.4, holly electric pump, fuel pressure and jets etc I'll check again later in day or tomorrow morning as I'm at work now. Oh and Taylor plug wires from Motorsport Z. I'll get a vid up also.

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I highly doubt it's the fuel especially since you state you only have trouble above 60. I have had cars sit for a year with no ill effects. Fuel pump is unlikely but possible. I had a bad mechanical pump that caused stuttering in my 510 but it would only happen whenever I went WOT. I would venture to guess it's all in the jetting. IIRC, there are 4 jets in each carb and each one needs to be correct for individual things like idle, low speed, WOT etc. I would suggest getting the entire kit of all available jets for those carbs and find out which is for your high speed etc and start moving up or down one size at a time. Have you talked to Wolf Creek (Todd I think it is) about the jetting. He could probably give you a better idea about whether you are starting at the correct point. They did my Mikuni's as well and it took a few tries to find the ideal jets. The beauty is once you get them dialed in, they should be good to go unless you move somewhere with a significant change in elevation etc.

Here is a vid of the idle and rev....I need to make another as the battery of ipad ran out.

Mikuni Problems | PERPETUALROAD