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After running out of gas today, I figured my 50mpg with 145 mains had dropped to 30mpg with the 155 mains I got from a Triumph dealer that didn't fit well. Someone suggested they were for Mikunis. My question is- does the 155 on a Mikuni jet equal 155 on a TRiumph jet?Can't believe that change in jet sizes should make that big a difference, especially since I was only driving around 60mph, well off the main jet.
Unfortunately, not having my reading glasses with me, I turned the fuel to off instead of reserve and had to push the bike to a gaS station, which luckily was only 20 yards away. It takes 15 seconds to fill the float bowls incidentally.
 

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FWIW...when I was trying to get the main jets sized correctly before taking it in for a dyno run, I kept track of my gas mileage...with 150 mains, I got a little over 50 mpg--about six tanks used with the 150's...with 160 mains, I got a little over 50 mpg--only 3 tanks used before I went for a dyno run. I had a least 2 and sometimes 4 spool-ups through the gears to the 8100 rpm rev limit on each tank of fuel. I live in the flat country and weigh 175 lbs. I ended up with 158 main jets after the dyno run.

Larry
 

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your right, at that speed the mains don't come into play, I would say you were probably in the pilot range, borderline needle.

What are your pilots?

Remember the CV's work on throttle position, not rpms.

Even with my HSR's I get 45, unitl I wrench on it.

Greg
 

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the original question of whether mikuni 155 is the same as triumph 155.. I have found differences in sizing in different name brand jets, sometimes the sizing is specific to certain applications. It is therefore best to stick to the correct jets, unless someone or yourself has sized them physically, not just assumed the same number means the same thing.
G
 
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