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Discussion Starter · #1 ·
Im new here, and for my first post im going to do a little introduction(Will be needed).



In my current possession is a custom made tubular frame go-kart, the twist is that the power plant in this little bugger is non-other than a CX500 engine. The whole thing was made by my wonderful father who in his infinite patience crafted this over the course of 3 years. It was finally finished when i was around 12(am currently 20), needless to say as a child i couldn't understand the great feat he just made for me. It came to be the first vehicle i learned stick in(sorta), i also learned the dangers of speed(nerf bars on the sides and front bumpers were added). Now that we have addressed the main part of the reason im here i can post some pictures
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Heres how i got it after 6 years of setting. Front tires dryrotted, the whole motor had been overheated many times due to poor ventilation/ cooling design, it only runs on one cylinder now, suspension is shot. But its a great base for a project with lots of "fun potential".







Might post a build thread to keep the information up to date.
 

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Welcome to the CX/GL500 forum. Your Dad is my new hero. That's a great looking go-kart.



When tuned properly, CX500 engines don't run that hot but you've got to keep the system full of coolant. In your case the radiator isn't going to get good air flow being backwards. An easy work-around is to ditch the camshaft mounted fan and install an electric fan. Is there a coolant overflow jug? CX500's have them and they're barely required but with your backwards/restricted airflow layout, you need one.



The custom exhaust will require some sort of change to the carb jets. Maybe your Dad already did this but check with him.



These motors are way easy to diagnose and fix. Keep us posted as to what's happening with it.



Where are you located? Add that to your sign in. There might be a fellow CX'er nearby that has spare parts, tools, advice who'd be happy to help you out.
 

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Discussion Starter · #3 ·
As things sit now i bought a second carb for it(current going through that because it sat for 10+ years), and doing other general maintenance. One of the biggest problems im having now is the one cylinder not firing, we narrowed it down to just the carbs. The things we checked were ignition, if the cylinder was getting fuel(took the headers off). We determined it was the carb, but due to the fact none of us know anything about these carbs we couldn't fix it. Thus we ordered a second carb off ebay, got the thing and its in all sorts of bad shape(figure i can use it for parts). Currently im cleaning that one out, the smell of old gas still wont leave my hands. Ive cleaned all the passages for fuel, the jets, the little tube one of the jets goes in, the holes that hold the jets, the floats, and little pieces that go along with that, the top assembly, the linkage, and butterfly's. I havnt been able to put the carb back together, but i'll address that little puzzle tuesday(the linkage is very confusing).
 

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Discussion Starter · #5 ·
Welcome to the group. Any chance we can get a shot of how the chain drive works?


Can do. These are the only picutres i could fish out for now. I can take some more detailed pictures tuesday, just let me know what in specific you want to see.





one of my friends in the seat



 

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Oh man, that drive arrangement is too cool!



I assume you have spark on both plugs so that's why you zeroed in on the carbs. Yep, these motors need clean, properly set up carbs to run properly. They must also be synchronized. That way, both cylinders will do an equal amount of work. If they're not sync'd motor will run poorly or sometimes not at all.



Let us know when you've got your carbs together and we'll go from there.
 

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Discussion Starter · #8 ·

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When reassembling the carbs, here's some things I've learned through my own experience with owning two CX500's and two GL500's. Float height is really important. I don't remember the spec but it's available in the downloadable CX500 manual. You take a steel ruler to measure the hang of the float. Bend as necessary to get to the spec. This is easy but really important.



When you have the carbs all put back together, look at the butterfly valves. They should be opened the exact same amount. If you can see that one is further opened or closed than the other, adjust the little screw on the spring loaded linkage that goes between the two carbs. Once you put the carbs back on the motor, you'll sync the carbs which means adjusting this screw again but its good to get it in the ballpark while you can actually see it.



A quickie test you can do to the carbs while off the bike is to use a shop vacuum cleaner on them. Hold the vacuum hose up to the side of the carb that's toward the motor. The slide should rise smoothly as you get closer and closer with the vac hose. Compare the operation of both carbs. Obviously if they don't act exactly the same, there's a problem somewhere.
 

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Your dad did a wonderful job on that. Lots of thought from him. I'm sure you love him.
 

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Considering that (properly tuned) the engine puts out about as much as an old VW engine based dune buggy it's going to be a mean machine. I do hope the gearing is right, these engines are basically idling until they get above around 5K rpm.



Too bad there's no real way to reverse the fan, a good electric will solve that though but you'll have to make sure it fires rearwards in that setup. The fan Old Okie and I put on mine came from a Suzuki GSXR1100, a bit of overkill but preliminary tests show it's barely going to be needed thus the reason I'm putting together the variable speed controller together so it can spin only as much as it needs to. He got it up to a bit above normal operating temp yesterday, switched the fan on and the temp dropped like a rock. 102°F weather at long stoplights isn't going to bother me a bit this summer and I've trimmed 2 - 3 HP worth of drain on the engine as well as not having to worry about that stupid fan blade exploding and taking the radiator with it.



Just got out of the hospital again so I'm hopefully back on that project pretty quick. Design is pretty much finalized, just have to get the final schematics, parts list and circuit boards made so people can build one themselves, buy it as a kit of parts or I can simply assemble them and sell them as a complete unit. There's another thread on this subject buried in here somewhere.
 

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It's true about the higher rpm's. She's starving for air until 5k and she'll ride like the wind from 5-8,000, and she LIKES it there......all day long!



Welcome to the forum. That IS a sweet looking cart there.



There's all kinds of posts in here on the cleaning of these carbs.
 
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