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Discussion Starter · #1 ·
I have been bringing a 1980 CX 500 back to life as a winter project. I have had the engine out and replaced the incorrectly installed replacement stator (was installed backwards and the rotor wore through the wiring harness) had the carbs apart several times to clean and adjust.

I recently replaced the stock cdi with an ignitech purchased from a forum member on the spring buy program.

On my most recent test runs the bike idles fine and run ok up to 5000 RMP. Above that RPM the power quickly fades and stalls at around 6000 RPM.

I have the stock jets in the carbs, 78 primary and 115 secondary.

Any suggestions as to what might be going on and potential fixes?

Thanks for your help.
 

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Are the jets in the right places within the carbs. Reversing the jets can give the same symptom. The 115 fits to the brass fitting. The 78 directly into the alloy of the carb.

Also, try a run up the street with the filter removed from the airbox as a blocked air filter will strangle the motor when you go for bigger revs/throttle openings.

Old or bad plugs is another possibility as well as bad plug caps.
 

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Discussion Starter · #3 ·
I have double checked the jet placement and they are correct. I am not running an airbox. Using pod filters and an aftermarket 2 into one exhaust system.
 

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Not that this is related to your issue but aren't the stock jets 78/112?
 

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Check that the ports are not being blocked by the pod filters, you should also probably be running 90/120 jets.
 

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Discussion Starter · #6 ·
I have modified the pod filters so the ports on the backs of the carbs are not blocked. The 115 jest are what were in the carbs. I have some 112 jets that came in another set of carbs. I have not gotten to adjusting the jets for the pod filters and different exhaust but I appreciate the advise for my setup.

Does it sound like it might be dirty carb internal ports? The carbs appear clean and I have removed all brass jets and they are free of blockage. I do have an ultrasonic cleaner but hoped I would not have to strip the carbs and ultrasonicly clean the carb bodies.
 
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