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Discussion Starter · #1 ·
First off some history. I purchased the bike and rode for about 20 minutes, on my way home, before it heated up. I stopped and checked it. Oil was boiling, because of all the coolant in it. The previous owner, admittedly not mechanically inclined, had put jb weld in the weep hole to "fix" the leak. I removed the jb weld and had no further problems, no weeping. I flushed the oil 2 times and no more coolant in the oil. I didn't drive it much but had no further problems. That was last year...
This year I am experiencing overheating issues and a grinding noise from the front area of the engine. I am thinking fan or valves. I have removed the air box and all the hoses that went to it and put on pods. So questions:
1. Do I block off the coolant overflow breather hose? It is spewing out antifreeze.
2. Engine noise. Is this more likely from the valves or fan? Can I check the fan for movement by removing the radiator and running it? Will it cause harm?

1982 Honda GL500 Interstate
10,000 miles
Sat for a couple years without care before I got it.
 

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I'd be assuming my grinding noise and overheating are related issues which would lead me to remove the radiator and check the cooling fan. These fans are 30+ year old plastic and they do fail.

Do not block the overflow, find and fix the cause of the situation.
 

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I'm betting your fan will finish breaking apart soon and then the grinding will stop and you can get back to riding... Kinda like how you fix problems in cars, you turn the radio up some more. "You hear that? Nope!"

Na, just pull the radiator off... takes maybe 10 minutes, you need a 10mm socket to remove 7 bolts. and undo the overflow line at the top, and the upper and lower line, just hose clamps. At that point you probably won't even have to crank the engine to see if the blade is any good. Hopefully the fan didn't twist off the end of your camshaft with it. But you can run the engine without the radiator. Obviously it'll overheat easy... so I wouldn't do it for more than 1 minute. Which is plenty of time to diagnose the problem.

David Silver Spares USA - Honda GL500 DC SILVERWING Radiator fan
 

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I'm betting your fan will finish breaking apart soon and then the grinding will stop and you can get back to riding... Kinda like how you fix problems in cars, you turn the radio up some more. "You hear that? Nope!"

Na, just pull the radiator off... takes maybe 10 minutes, you need a 10mm socket to remove 7 bolts. and undo the overflow line at the top, and the upper and lower line, just hose clamps. At that point you probably won't even have to crank the engine to see if the blade is any good. Hopefully the fan didn't twist off the end of your camshaft with it. But you can run the engine without the radiator. Obviously it'll overheat easy... so I wouldn't do it for more than 1 minute. Which is plenty of time to diagnose the problem.

David Silver Spares USA - Honda GL500 DC SILVERWING Radiator fan

1. DO NOT block off the overflow lines... it has to come out somewhere because it's overheating... if you plug it up, it'll just find the weakest spot in the system and blow it out.
2. I've never heard of grinding valves... I'd def say it's the fan. Valves usually tick and clatter... Does it crank and run fine besides the overheating? If so, then it's not the valves. If you have valve clatter just adjust them. But they shouldn't be grinding.
 

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1. Do I block off the coolant overflow breather hose? It is spewing out antifreeze.
The rubber hose going into the coolant reservoir ?
How much coolant is still in the radiator ?
I think it's a sign of a burned/blown cylinderhead gasket.
If the engine is running have a look into the rad -without cap- and watch for bubbles.
Or do a leakdown test.
 

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Discussion Starter · #6 · (Edited)
Well thanks for the replies. Sorry for the delay. I eliminated the grinding noise with a valve clearance and timing chain tension service. Im assuming the noise was chain related. I checked the fan. Looks like a 30 year old piece of plastic. There are some noticable wear spots where it must have been hitting something. I checked for flow in radiator. It was moving coolant at op temp. I will soon upgrade to an electric fan and better performing radiator with custom overflow tank.
I rode it all day yesterday and noticed minor oil leaking at tensioner adjusting nut and clutch lever seal. The temp was pretty high at times, almost redline, but seemed to correct itself by dropping to half of the thick white line.
I took it out today and noticed the clutch plates sticking ( it tried to creep forward in first with the clutch lever in) a subtle rev freed them up. I adjusted it with no avail. Also after 20 minutes of steady 60 mph it jumped to red line on temp gauge and stayed until I shut it off.
I figured I would put In some Lucas oil stabilizer to help the clutch.
I opened the oil dipstick with a hot engine on the side stand and oil poured out. The viscosity seemed unusually low. Is this common? There is no coolant in oil but valve covers smelled slightly of fuel. The floats are adjusted properly. Im leaning toward head gasket again?
Thank you.
 
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