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CB200 won't idle under 3000

ctap3

New Member
Joined
Mar 20, 2023
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Location
Los Ángeles, CA
CB200 won't idle under 3500

Hey guys, picked up my first bike a few weeks ago and after cleaning the carbs multiple times and reading a ton of the posts here, I still can't get it to idle under 3500. Will die with a bit of throttle from idle sometimes as well.

Carbs looked clean and no gunk anywhere, but do they still maybe need a rebuild? Something else I'm not thinking of? This has to be carb related, right?

IMG_2279.jpg
 
Air leaks in the intake?

Are the O rings okay?

Have you taken the carbs off, removed the jets,

Cleaned them and the jets,



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Previous owner used gasket shellac on the intake, I've checked multiple times for air leaks and couldn't find any. Spraying starter fluid around the intake didn't do anything either. O rings look great. I've taken all the jets out, cleaned with car cleaner and there wasn't any gunk or dirt in them, could see right through them.

Tried tuning the carbs per 66Sprint's guide, but couldn't get that to lower the idle either.
 
Carb slides are in the correct way, notched facing backwards. Tried flipping them the other way just to check and it wouldn't run at all.
 
Wondering if the jets are drilled out, thinking I should just bite the bullet and rebuild the carbs and 100% know that's not the issue.
 
ctap3 said:
Wondering if the jets are drilled out, thinking I should just bite the bullet and rebuild the carbs and 100% know that's not the issue.
Click to expand...

If you do that, know that most carbs kits have incorrect brass parts in them, everything from float needles to jets incorrectly sized. You could easily end up as bad off in a different way. If you have any doubt you should identify the stock jets and sizes and buy them from JetsRUs Use the link in my reply to your introduction (our Welcome Package of links) to learn how to identify and sewarch for parts for these bikes, finding the part numbers is the right place to start. And for the jet sizes go to the link in the package for the FSM library and download the manual for your bike.
 
Appreciate the advice on the jet sizing, I'll order a new set for both carbs and see if that does anything.
 
You probably won't like this idea, but if it were mine I would be searching for a set of OEM air boxes, air filters, all the related mounting hardware, and a decent exhaust system with some mufflers. That might make it run better.

Whatever you decide to do, it is never a good idea to place the exhaust outlet almost piped into the air inlet. That holds true for cars, trucks, tractors, and motorcycles.
 
My guess would be air leak at the headers. What part of town are you? I might be able to swing by for a check
 
i'm not an expert on these carbs but i think the slides are left, right carb specific also. make sure they are oriented correctly. Or maybe they already have aftermarket brass parts that arent sized properly.
 
Even with those crappy air cleaners and short exhaust pipes, it should be possible to get it to idle. Spark advancer working correctly? Pull the spark advancer off the end of the cam, with the drive pin in the cam pointed up at 12 o'clock is the timing pointer on the crank located at TDC ?
 
If spark is set very retarded, high rpm is all that will enable it (with mechanical advance) to run. Check your timing.


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