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New Mikuni carb for CT2 top end bike

  • Billy Mild
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New Mikuni carb for CT2 top end bike was created by Billy Mild

1971 Yamaha AT-1c with a CT-2 reed valve induction. I just purchased a brand new real Mikuni VM26 carb from Amazon. 

www.amazon.com/dp/B072F1JZBQ?psc=1&ref=p...dt_b_product_details '

Does anyone have suggestions on what I should use for jets in this with my current motor setup. Main jet is 190, Pilot is 22.5. The pilot looks a weebit small, but also the needle is different number as well. 

Any suggestions would be great. 
25 Jul 2022 10:51 #1

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Replied by Mothersbaugh on topic New Mikuni carb for CT2 top end bike

Just sold my CT-2 yesterday for a nice price. Had a Sleeper Pipe on it, and I live in Wyoming at 6000 feet. Summers lately are 90's during the day and 60's at night. I had settled on a 25 pilot at Dave Meis's suggestion, and a 200 main based on trial and error. What altitude and climate are you working in? Makes a difference.
25 Jul 2022 20:31 #2

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Replied by Billy Mild on topic New Mikuni carb for CT2 top end bike

I'm in Kansas City, so closer to sea level maybe 1000 ft higher. Climate is 70-90's here.
26 Jul 2022 07:53 #3

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Replied by Billy Mild on topic New Mikuni carb for CT2 top end bike

I noticed the slide cutaway and needle are different from the stock carb vs. this new VM 26

VM24 Stock carb
Needle: 4F15
Slide 2.0

VM26
Needle: 5E75
Slide 1.5
27 Jul 2022 14:52 #4

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Replied by Billy Mild on topic New Mikuni carb for CT2 top end bike

The stock carb settings actually work fairly well. It starts and idles now, but I did change the pilot jet. I went with a 25 pilot jet. The 27.5 pilot jet wanted the air screw almost all the way out. I'm keeping the same slide and needle that came with the carb. 

My running issue originally was caused by a fouled incorrectly gapped plug. I changed carb settings before changing the easy thing first. I will start to try and ride and see how it runs. 

Around the block it will powerwheelie without an issue in first gear. 
04 Aug 2022 16:23 #5

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Replied by MarkT on topic New Mikuni carb for CT2 top end bike

Nice work!   

I probably said this already...  Yes, the generic carbs are often "close" with jetting. 

Sounds like yours was very close!  

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1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
04 Aug 2022 16:52 #6

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