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Discussion Starter · #1 ·
Hey guys! Just took the CX500 out for a ride today and noticed that when I really got into it accelerating up a hill, the engine would pull fine until around 5500rpm and then it would bog down. Almost like it had a rev limiter. The bike runs great and has tons of power up until that point. I think the carburetors must just need to be richened up a little on the high end. Now I know that these carburetors have to be in sync with each other. How do I make sure of that? Do I use a vacuum tester or just make sure the same screws on both carburetors are equal turns out? My other thought is that the carburetors might not need adjustment, but that because someone ported the pipes on my bike (it's obviously louder than stock) that the jets need to be drilled out or replaced with a bigger set. Could this also be an issue with the air filter and not enough air getting into the carburetors? Do any of you run the small pod filters on your carbs instead of the stock air box? Give me you feedback and advice!

Thank you :)
 

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If you are hitting a rev limit effect at 5000-5500 rpm that sounds more like a stator issue. That is where the stator changes windings. Look in the wiki links to check the stator through the 3 yellow wires.
 

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Discussion Starter · #4 ·
So nothing to do with the carburetors huh? Where is the high speed coil located and how do I go about changing it?
 

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The high speed coil is part of the stator and to change it you need to change the stator……..first run the tests to see what figures you are getting, so diagnose it properly first then if it is the high speed coil, go and order on and change it. But for this you will need to drop the motor and remove the rear cover, which means a bunch of gaskets and o-rings + the stator
 

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If the stator is bad, it is cheaper, and better (my opinion) to replace the stator with the less expensive and higher output G8 rather than the G47. And replace the CDI box with the Ignitech. The combination of G8 and Ignitech will be less than the cost of a G47 and you won't have a CDI to fail you in the near future.
 

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to correct some mis information

the factory cdi system is a wonderful thing to have in a bike if it is working properly

it lets you bump start your bike even if the 12 volt system is fried and the battery is dead or stolen and still get home

it functions completely independent of the rest of the electrical system

as for cost here you go

a cdi g47 stator from rm stator the brand i use is 85 dollars

Generator Stator Honda CX 500 CX500 1978 1979 1980 1981 | eBay

from ricks motor sports it is close to 180

there are other companies in england i can get them for around 145 landed

andy62 makes a brand new cdi box for 100 dollars

so the statement "The combination of G8 and Ignitech will be less than the cost of a G47 and you won't have a CDI to fail you in the near future. "

is just not so a g8 is around the same 80 dollars and a ignitech is around 175???
 

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the G8/ Ignitech swap works. It is not cheaper. Do the test before you pull things apart.
 

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hmmm................ one should consider the G8 + Andy CDI.. The original CDI lasted for 30+ years. Any of your guys planning on riding in 2044? Ignitech is nice but there are other less expensive viable options.

I had a CDI that was failing. Wasn't real keen on shelling out for the Ignitec. Came across Andy62"s option and bought it. Absolutely no regrets. plug straight in, secure the box, replace the seat went riding. His total price with shipping was just over $100 USD. I figure if his CDI runs until I'm done with the bike 'nother 5-10 years. Then I made a wise choice.

I also didn't need to drop the engine because the stator was fine.
 

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I have been all through this one and I would say clean your carbs really well first. It costs nothing if you are careful. There is a lot of information on here as how to go about it. If that doesn't fix it check the high speed winding. If it is shot you can decide wether you want to take the bike all apart and replace the Stator or just buy an ignitec It just uses the charging windings. You can still push start it as long as you have a battery to get your initial spark.
 

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Discussion Starter · #12 ·
So, I can fix this problem (if it is the high speed winding) by putting in an ignitec CDI? But it will charge less efficiently but I won't have to drop the motor?
 

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The ignitech will sort your ignition problem if the fault is with the CDI stator windings. The bike will continue to charge as it always has, with the caveat that the charging system will now be required to run the ignition.

The G8 stator often fitted with the ignitech puts out 250 watts where your current [G47] stator only cranks out 170 watt.

This is usually enough.
 

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Discussion Starter · #14 ·
Good, because I really do not want to drop the motor to switch the stator even if it is an upgrade.
 

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Discussion Starter · #16 ·
Yeah I will do the test. Just use those resistances on page one of this thread by the picture right?
 

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Discussion Starter · #18 ·
I decided that before I would do the resistance test, I might as well drop the bike in 5th gear on the center stand and rev it up to see if it still was hitting that limiter like I thought and it didn't do it. I did 3 runs the same way. All three times it revved right up to 9k rpm without any problem. So, if it only does it when there is a load of my weight on the bike, would that mean that this is probably a carburetor issue? No dimming or change in lighting when I hit those rpm's either.
 

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FWIW, I had the same symptoms and after reading here I assumed it was a failed CDI or high speed winding. However, it turned out to be my old ignition coils. The resistance of both the primary and secondary windings tested okay but they were breaking down electrically at high speed apparently. Changing out the coils fixed it.
 
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