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1980 Honda CX500C
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Discussion Starter · #1 ·
Ok, so someone brought me a 79 CX500D to work on. Said there was an oil leak. Turns out, the crankcase was filling with fuel, completely full and the mixture was spewing out everywhere.



Simple, it means the float needles are sticking open, right?



I get it apart and pull the needles out. The needles are not rubber tipped (but dont have any indication that they ever were, they look like any solid metal needle should. But the real kicker is that there isnt a rubber O-ring seat for the needle to seal against. Obviously, a stainless needle wont seal against a brass seat, so something is wrong here.



Either someone bastardized this thing with incorrect parts or the rubber seats fell out in a carb cleaning. The owner denies anyone having worked on it, claiming it just suddenly started doing this. I know its bullshit, but whatever. The funny thing is that he rode it like this until the leaking got "pretty bad"...well no shit dude! There was a quart of oily gas in the airbox too.





SO, my question is simple. I was under the impression that all the needles were the same for all the CX500's (rubber tipped).

If they arent, I am not seeing a rubber seat for this model of CX in the parts fiche. Both carbs have the same issue, so it isnt like one side disintegrated.

I am pretty sure I can just order a set of the needles and install them, and all will be well. I only planned on buying OEM here, I've read some horror stories about aftermarket ones.



Classic case of a dumbass with a wrench doing his buddy a favor. I know the owner didnt personally work on it, but its obvious someone else had.



On a side note, what is at the top of the block that would start to spew oil upon extreme overfilling? I really dont have any motivation to pull the motor to start chasing an oil leak that probably only surfaced because the block was FULL of oily fuel.....
 

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I have never seen needles that did not have rubber tips.



I would think that if it were flooding that bad it would have ran really bad,,also I would expect there would have been gas draining from the overflows unless they were blocked.
 

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I grew up on a farm and know very well the smell of BS - I'm with Shep - smelling it here.

Are you a farm boy too Shep?? :)

You will probably never know the truth - best to just deal with it and get the job over with using the right parts.
 

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I smell BS too because I just bought a new needle for one of mine and it was rubber tipped that was the problem with mine gas getting into the airbox so new needle and now I'm hunting down a float bowl.
 

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What you call needle valves are not the float valves. Take off the bowl, slide out the pin. remove the float and then remove the float valve. It is rubber tipped. Keep both sides separate so they go back into the asme carb.
 

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1980 Honda CX500C
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Discussion Starter · #9 ·
What you call needle valves are not the float valves. Take off the bowl, slide out the pin. remove the float and then remove the float valve. It is rubber tipped. Keep both sides separate so they go back into the asme carb.




These are not rubber tipped. solid metal, like in a lawn mower that uses a rubber seat. funny thing is, other than that, they are identical to the rubber tipped CX valves.



the guy claims it ran fine, but again, i think its bull squat. the overflows do not flow, they are plugged internally with something. gona clear them out when i reassemble the mess
 

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Buy 2 new float valves either on line of from a dealer. Note that there are 2 types of valves. One for floats that are 2 black plastic tanks held together with a piece of metal and a second where both floats and the pivot structure are all one piece of white plastic.
 
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