[Setarian]

ok- 1983 cx650 c with 19k miles. sat in barn for 6 years. drained oil... was milky. rebuilt the carbs. installed new oil/filter. bike starts and idles. when its cool, the bike drives well. as it heats up it loses power rapidly until it dies.



could a head gasket cause this? im replacing both anyway, but i want to know if i am barking up the wrong tree. the new oil isnt milky, but its 20/50 and hasnt seen a lot of use.

 

[philbrewer]

If sitting for 6 years pull the carbs and go through them. They want you to clean them!

 

[Setarian]

the carbs are really pretty clean, as i said i already rebuilt them, its the first thing i did.

 

[Blindstitch]

Outside clean and inside clean are two different things.

 

[FOWG]

Milky oil is usually coolant leaking into the crankcase. Head gasket, cracked head or a nasty crack somewhere else. Have the heads magnafluxed when you pull them for the gaskets you plan to replace.



I would try to isolate the leak before doing anything more. It may not be worth relacing the gaskets or anything else.

 

[Shep]

Do a compression test 1st to see if it is a blown head gasket.



I suspect the carbs are not as clean as you think they are plus you may have faulty coils.Also check the fuel cap vent hole is not blocked causing a vacuum in the fuel tank thus impeding fuel delivery.Also check the float heights are exactly set to 15.5mmm as per,



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[Setarian]

Rebuilt the carbs... Meaning I pulled them down to nothing, soaked in cleaner, detalied all parts, and reassembled. That bein said, I'll take another look. As for the coils, that's something definately worth looking into. What is the best way to test them?

 

[richnct]

Does it start and idle (when cold) without choke? After it stalls, are the plugs black or sooty, or wet? If the carb is set rich, or float level is too high, or flooding, one would expect the symptoms you are experiencing. Look for any carb overflow leaking. Also, be sure the carb jets are not in the wrong holes. Another possibility is fuel starvation, check the vacuum hose for split ends (leaking air in and not opening the vac fuel tap fully) or the tank filter sock clogged up. Pull the fuel line off the carbs and suction the fuel tap open, looking for copious fuel flow.

 

[Shep]

Rebuilt the carbs... Meaning I pulled them down to nothing, soaked in cleaner, detalied all parts, and reassembled. That bein said, I'll take another look. As for the coils, that's something definately worth looking into. What is the best way to test them?

For a CDI engine set of coils you set a multimeter to the 20k Ohm setting and between the Thin wire and the HT they should read around 7.5k Ohms/Resistance.For transistor ignition I don't know but I would do the same test and see if either coil varies from the other drastically no matter what the readings are.

Problem with coil heat breakdown is it's hard to test until the bike is hot and under load.

 

[Setarian]

Yes it starts nicely and idles without choke. I'll take a look at those things