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Discussion Starter · #1 ·
Went on a ride longer than 2 miles for the first time since the bikes been running. I looked at my temp gauge around mile 9 and it's in the middle of the fat white line. Mile 10 it's in borderline white/red. Luckily I was close so I went home immediately. Everything felt fine. I let the bike cool for a few hours and cranked it up again. This time I let it idle for about 5 minutes and the temp was normal so I took it around the block. About 2 miles later it's borderline white/red again. Now when I ride to work (2 miles away), it's going to the white/red. I've been reading up on here, but I just wanted to rack the brains of the CXGods before I dive in.

-the radiator fluid was changed about a month ago, but I didn't do a full flush. Check the fluid this morning, it's full but the bike is cold

-could a bad radiator cap cause this?

-air pockets? is there a way to 'check' for this?

-how often does the mechanical seal/water pump area need to be serviced or replaced?

-7V regulator was the first thing I changed on the bike after I bought it. I got it from here. I assumed it would be adequate.

-I'm not running with a thermostat



Thank you in advance for all of your help!!! I would be lost without this forum.
 

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-the radiator fluid was changed about a month ago, but I didn't do a full flush. Check the fluid this morning, it's full but the bike is cold

-could a bad radiator cap cause this?

-air pockets? is there a way to 'check' for this?

-how often does the mechanical seal/water pump area need to be serviced or replaced?

-7V regulator was the first thing I changed on the bike after I bought it. I got it from here. I assumed it would be adequate.

-I'm not running with a thermostat



Thank you in advance for all of your help!!! I would be lost without this forum.
Take the rad cap off, run bike until it gets warm, if there's an air pocket, the fluid will drop as the air comes out the cap, I'd let it sit there and run no cap for 20 minutes, just check on it here and there at least. A full radiator flush wouldn't be a bad idea to. How long have you owned the bike, and have you done it? Assume the previous owner hasn't done anything to it ever. If you haven't done it, I'd say it hasn't been done.



The mechanical seal shouldn't affect the temp, it may leak, but it shouldn't stop things from working



Once you know it's run long enough to be "burped" and you re-top it off, crack the throttle and watch the fluid, it should go down a bit at higher rpm's typically, at least it does with cars
 

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$34.99.??

Sheesh you could have nade yer own for a dollar or two



If we assume the 7vreg and gauge are ok

and the rad is topped up

( you did check coolant levels in the rad and not the bottle I hope?)



I'd guess at a posbble circulation fault

blocked rad, airways or coolant passages.

Impellor not pushing the coolant about due to

possibe stripped splines

As you have no thermostat we cant point to that
 

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Discussion Starter · #4 ·
Take the rad cap off, run bike until it gets warm, if there's an air pocket, the fluid will drop as the air comes out the cap, I'd let it sit there and run no cap for 20 minutes, just check on it here and there at least. A full radiator flush wouldn't be a bad idea to. How long have you owned the bike, and have you done it? Assume the previous owner hasn't done anything to it ever. If you haven't done it, I'd say it hasn't been done.



The mechanical seal shouldn't affect the temp, it may leak, but it shouldn't stop things from working



Once you know it's run long enough to be "burped" and you re-top it off, crack the throttle and watch the fluid, it should go down a bit at higher rpm's typically, at least it does with cars
I've owned the bike for a few months now. Based on the other problems i've encounter thanks to the PO, I should have assumed it hadn't been done. Hopefully I can find a place to do it. Working on the bike in my apartments garage is hard. If I get caught I get fined.





$34.99.??

Sheesh you could have nade yer own for a dollar or two



If we assume the 7vreg and gauge are ok

and the rad is topped up

( you did check coolant levels in the rad and not the bottle I hope?)



I'd guess at a posbble circulation fault

blocked rad, airways or coolant passages.

Impellor not pushing the coolant about due to

possibe stripped splines

As you have no thermostat we cant point to that
Yeah, I checked the levels in the rad and not the bottle.

I ran into this problem before I found this forum, Reg. I would have made it myself now. I thought that was a good deal compared to getting one from Honda...
 

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A honda stealer would have scalped you if they had one

No matter



apart from circulation probelms a leaky head gasket could overheat the coolant



I had that happen but it was evident fron the expansion bottle

filling up
 

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I've owned the bike for a few months now. Based on the other problems i've encounter thanks to the PO, I should have assumed it hadn't been done. Hopefully I can find a place to do it. Working on the bike in my apartments garage is hard. If I get caught I get fined.







Yeah, I checked the levels in the rad and not the bottle.

I ran into this problem before I found this forum, Reg. I would have made it myself now. I thought that was a good deal compared to getting one from Honda...
That's why I just do it inside my house, but I own my trailer, they can tell me no vehicles outside being worked on for long, we're allowed to change tires, but rebuilding a car is a no go, but I just bring the bike I'm working on inside and use my "shop" lol



I'd make sure that it seems the antifreeze is flowing first, and that it's burped, also that the radiator isn't all banged up in the front as Reg mentioned if it's blocked up then it won't flow air properly.



I believe that if the water pump is working, the coolant should go down a bit when you crack the throttle and it's warm, although then again, no thermostat, it doesn't have to get warm...



When you filled the antifreeze, did you run the bike and fill it again? I forgot about the no thermostat thing, so when you check it out, you don't have to warm it up to check it out, so I'd just run it for 10 minutes with no cap, and watch it to see if it burps or gets sucked down when revved
 

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with no thermostat You'd expect the bike to run cool

Something else just occured to me and might be worth checking

even with a good 7V reg if it hasnt got a good ground commoned to

engine gound, it may put out too much voltage and overdrive the gauge

Rechecking the connections and grounds wont take long and will at least

help eliminate a suspect.
 

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You probably just need a good cleaning of the cooling system. It seems that just about all the bikes on this list sat for years and decades before we brought them back to life.



I recently put a seeming clean looking GL500 radiator in the ultrasonic cleaner. When it was done, there was 1/8 of an inch of a greyish white sandy substance coating the bottom of the cleaner. I dumped the solution too, as this crap was also suspended in the solution. Visually, the passages you could see in the radiator, didn't look all that different.



There is another thread on overheating on the board, the guy was going to do a flush with vinegar and post the results.
 

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I would put a thermostat in it, at least as a test of theory. I have seen cars with the t-stat removed run hotter than they did with the t-stat installed. Apparently the higher flow rate with no t-stat means the coolant spends less time in the radiator so it is not able to reject as much heat.
 

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Yhat would be interesting.

If the temp does come down that would suggest the pumps pushing

the coolant about so fast it isnt giving the rad enough time to absorb

and dissipate the heat.



Offhand, I wouldnt have thought the pump was that good, but who knows?

Worth a try.
 

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I would put a thermostat in it, at least as a test of theory. I have seen cars with the t-stat removed run hotter than they did with the t-stat installed. Apparently the higher flow rate with no t-stat means the coolant spends less time in the radiator so it is not able to reject as much heat.




exactly right, people seem to think taking it out helps. all it does it keep the fluid constantly flowing and spending no time in the radiator getting cool. that why you have a thermostat. sorry, i'm aq mechanic and worked on alot of old cars, i'm sure the same applies to any water cooled engine.
 

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exactly right, people seem to think taking it out helps. all it does it keep the fluid constantly flowing and spending no time in the radiator getting cool. that why you have a thermostat. sorry, i'm aq mechanic and worked on alot of old cars, i'm sure the same applies to any water cooled engine.
I agree that you need a thermostat for the reasons stated above and you should put one in,,but if this one is overheating as quickly as you say,,I doubt that is the problem in this case,,I would check the reg to be sure it is only putting out 7 volts.

As Reg said,,it could be a bad ground.
 

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I agree that you need a thermostat for the reasons stated above and you should put one in,,but if this one is overheating as quickly as you say,,I doubt that is the problem in this case,,I would check the reg to be sure it is only putting out 7 volts.

As Reg said,,it could be a bad ground.


true it is quick. but it is very hot out. my van gets up to temp in this weather in a couple minutes. plus i'd put a stat in and see were its at then. its at least the first kink in the chain.
 

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Discussion Starter · #14 ·
I'd make sure that it seems the antifreeze is flowing first, and that it's burped, also that the radiator isn't all banged up in the front as Reg mentioned if it's blocked up then it won't flow air properly.



I believe that if the water pump is working, the coolant should go down a bit when you crack the throttle and it's warm, although then again, no thermostat, it doesn't have to get warm...



When you filled the antifreeze, did you run the bike and fill it again? I forgot about the no thermostat thing, so when you check it out, you don't have to warm it up to check it out, so I'd just run it for 10 minutes with no cap, and watch it to see if it burps or gets sucked down when revved
The radiator circulates the coolant when the engine is rev'd. I didn't notice the the level dropping, but there was definitely movement. When the bike just idles, the temp is normal, when you start rev'ing the motor, the temp goes up fairly quickly.



I would put a thermostat in it, at least as a test of theory. I have seen cars with the t-stat removed run hotter than they did with the t-stat installed. Apparently the higher flow rate with no t-stat means the coolant spends less time in the radiator so it is not able to reject as much heat.
Headed to buy a thermostat right now.



Once I get the thermostat in, I'm going to check the voltages on the regulator.
 

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Discussion Starter · #15 ·
Got the thermostat and installed it. Seems to be running a little cooler, but didn't get it on the road. The voltages on the 7v regulator were fine. Looks like I'll be doing a flush over the weekend.
 

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Discussion Starter · #16 ·
Rode to work today. With the thermostat installed the bike still got too close to the red. An update after the coolant flush. I'm also going to double check the 7volt reg's status. I may have done a few things wrong when measuring last night.
 

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I would put a thermostat in it, at least as a test of theory. I have seen cars with the t-stat removed run hotter than they did with the t-stat installed. Apparently the higher flow rate with no t-stat means the coolant spends less time in the radiator so it is not able to reject as much heat.
Adding a thermostat isn't going to make your bike run cooler, however, you should be running with a correctly working thermostat at all times.



Let us know after you correctly test and make sure that the 7v regulator is working properly.
 

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Why don't you get a thermometer (like a turkey one) and check your coolant temp to "sync" your gauge? IIRC fully warmed up should be running around 170 degrees F.



On my 650, when she gets hot I know it, I can feel the radiation, and she tick tick ticks when I shut her down.
 

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Discussion Starter · #19 ·
I haven't figured out how to check the 7V Regulator yet, but I did soak my radiator in vinegar last night. Got a lot of extra junk out so I'm glad I did it. I'm going to flush the system with it tonight after I get off work. I also took another look at my radiator and the fins were a lot more jacked than I remember them being so they're straightened up as best as possible now.



I've got 2 questions:

1-Does the radiator have a rubber gasket anywhere on it? I found this in the tub when I got to it today. (top right)



Do you think this is #1 in the pic below?





2-I'm new at voltage testing--When testing the voltage regulator, how/where do I do this? I've searched a little on here, but can't seem to pin it down. I tested the voltage at the temp gauge in the thermostat housing and I think it read somewhere in the 8.3 range. I feel like that's too high or I'm measuring this wrong. I read through this, but I'm still a little confused... I briefly browsed the forum, but didn't see a step by step...maybe I missed it.



Thanks in advance.
 

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Yes, the radiator drain plug comes with a black sealing gasket, looks like that's it.



Can't help with the regulator testing, my gauge was so obviously off that I replaced it with one of Marshalls' kits sans testing of the old one.



If it still has the fragile plastic plug, do yourself a future favor and replace it with a brass one, they're about $3 at most parts stores.



 
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