Author Topic: Please help diagnose carb problem  (Read 619 times)

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Offline daveybaker

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Please help diagnose carb problem
« on: July 30, 2019, 05:06:31 PM »
Hello, and I hope I'm posting this question in the right place. The No. 2 carb on my cb350f consistently floods after the bike is good and warmed up, after about 25 minutes of riding. The carbs were recently cleaned and had new everything from a rebuild kit. Is there anything I can tinker without removing the carbs to fix it? Thanks very much in advance!

Offline whizzer

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Re: Please help diagnose carb problem
« Reply #1 on: July 30, 2019, 06:29:50 PM »
Sorry. I too used new kits before reading here the benefits of cleaning and refusing original brass. I removed carbs 12 times before getting advise to use clear tube method to set float height, not the stock setting. With new brass floats had to be 26 and not 24. Flooding at 24.  Search for clear tube method.  Search for easiest way to remove carbs. I ended up using broom handle to nudge them off and on. Keep them on their rack as a set even to work on one and post pictures here.  Simple carbs and easily sorted with advice here. Yes, you can fiddle with floats while carbs on bike but so much easier on bench.
72 cb350f
66 cb77 sold
72 Suzuki gt750 given away
59 Vespa given away
06 Whizzer sold

Offline cjespersen

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Re: Please help diagnose carb problem
« Reply #2 on: August 01, 2019, 08:48:30 PM »
I had the same problem with my CB350F. I used aftermarket parts and had issues with my float height. The float valve needles and seats are a little taller and stiffer then the original so you may need to adjust float height on your number 2 carb. The clear tube methode works. You can purchase one already made up.

https://www.ebay.com/itm/Honda-Carburetor-Float-Fuel-Level-Gauge-Tool-cb750-cb450-cb350-cb77-cb-carb-gas/392139638395?_trksid=p2485497.m4902.l9144
« Last Edit: August 01, 2019, 08:50:18 PM by cjespersen »

Offline scott jones

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Re: Please help diagnose carb problem
« Reply #3 on: August 02, 2019, 01:19:01 PM »
I had the same problem too with my cb500. 627b Keihin carbs. Had them apart 3 or 4 times, rebuilt with aftermarket kits before i finally put the original brass back in. Reset the float levels & all good now. I read where the original brass is better than the aftermarket stuff. I did get new main jets from JETS R US. Good people to deal with.