Honda CX 500 Forum banner
1 - 20 of 38 Posts

·
Registered
81 CX500c, 83 GL650i
Joined
·
331 Posts
Discussion Starter · #1 ·
Took the 650 out for a 30 minute ride this afternoon. Noticed that the bike seems to be running on the hot side. It's a very mellow day today here in Boise - temp is around 75 fahrenheit.

Odometer Motor vehicle Gauge Automotive tire Speedometer


With my cx500, the needle tends to remain at the second hash mark between T and E.

I checked my coolant and the radiator is full. I did notice that it has orange radiator fluid, which I'm not familiar with.

Should I be concerned?
 

·
Registered
Joined
·
7,984 Posts
The 650 with the Elec fan tends to run a bit hotter than the 500's I asked Murray about this a while back and he confirmed what you are seeing is pretty close to normal
 

·
Super Moderator
'84 CX650E that is evolving into a GL500
Joined
·
19,282 Posts
What you are seeing on the 650 is closer to the optimum operating temperature. With their non-clutch and non-flex fans sucking air through the rad all the time CX&GL500s are over cooled.
 

·
Registered
Joined
·
36 Posts
What you are seeing on the 650 is closer to the optimum operating temperature. With their non-clutch and non-flex fans sucking air through the rad all the time CX&GL500s are over cooled.
I removed the fan on my 500 about 3 decades ago. It still runs coolish on a nice day and it takes a true Australian summer and traffic to get the needle 3/4 the way up or higher.
 

·
Registered
81 CX500c, 83 GL650i
Joined
·
331 Posts
Discussion Starter · #6 ·
When I went out the other evening, I'm pretty sure that the temp gauge crept all the way to the "P" - which is very, very close to the red-zone (at least to me) - It has me worried with being so close. Do I only consider the bike to be overheating if it crosses into the red threshold? What if it's still in the "white" but literally right next to the red area?

I've also only noticed my fan coming on once. I'm beginning to wonder if I need to look at replacing my rad fan switch? Or getting a switch that triggers at a lower temperature? I've started doing some research in old threads and found this one that was interesting.

GL650 thermoswitch operation

With my ignorance of this motor and it's normal temps, along with my total unfamiliarity with electric fans and how/when they are supposed to work, I want to make sure that I don't inadvertently run this bike dangerously hot while thinking that its normal. Makes me miss the mechanical fan on my 500, ha! What limit/parameter on the temp gauge (under normal driving conditions) should I begin to take action?

I'll try to take it out again and see what kind of temps I get and report back. I will note that it does have a new 7v regulator from Murray on it.
 

·
Registered
GL650
Joined
·
457 Posts
When I went out the other evening, I'm pretty sure that the temp gauge crept all the way to the "P" - which is very, very close to the red-zone (at least to me) - It has me worried with being so close. Do I only consider the bike to be overheating if it crosses into the red threshold? What if it's still in the "white" but literally right next to the red area?

I've also only noticed my fan coming on once. I'm beginning to wonder if I need to look at replacing my rad fan switch? Or getting a switch that triggers at a lower temperature? I've started doing some research in old threads and found this one that was interesting.

GL650 thermoswitch operation

With my ignorance of this motor and it's normal temps, along with my total unfamiliarity with electric fans and how/when they are supposed to work, I want to make sure that I don't inadvertently run this bike dangerously hot while thinking that its normal. Makes me miss the mechanical fan on my 500, ha! What limit/parameter on the temp gauge (under normal driving conditions) should I begin to take action?

I'll try to take it out again and see what kind of temps I get and report back. I will note that it does have a new 7v regulator from Murray on it.
You're OK bro. Mine runs right there all the time. I guess the 500s do show a little cooler operating temp on the gauge. My fan usually comes on only when sitting at idle on a hot day.
 
  • Like
Reactions: lukaspriest

·
Super Moderator
'84 CX650E that is evolving into a GL500
Joined
·
19,282 Posts
Anywhere in the wide white part of the scale is normal.
The narrow white part is low (I saw that a lot in the middle of winter but you probably won't except when it hasn't warmed up yet).
The red part is of the scale is red to warn you that the needle should not be there.

Note that internal combustion engines perform best when they are at about 95c(205f). Too much higher and things expand too much and can seize, too much lower and things don't expand enough to work properly plus the oil may not get hot enough to boil off moisture & contaminants.
 

·
Registered
Joined
·
36 Posts
Well you could always wait till the engine is cold and open the radiator cap and check there is coolant in the engine. I bought a VFR800 that only had 1 litre of coolant in the engine ............ but the reserve tank was full. The cause was the previous owned lived at the end of a long dirt road and dust had accumulated in the reserve tank and eventually solidified into a lump blocking the line.
 

·
Registered
81 CX500c, 83 GL650i
Joined
·
331 Posts
Discussion Starter · #10 ·
So, I just got back. I can confirm that I have coolant - I checked that the other day and my radiator is full.

I just got back from a 30 minute ride that was split up by about 10 minutes while I grabbed a quick bite to eat. I then rode home, about a 15 minute ride.

Just as I pulled into my parking lot, this was the temp gauge:

Motor vehicle Automotive tire Automotive lighting Hood Vehicle


That can't be good.
 

·
Registered
Joined
·
2,900 Posts
That is not normal IMO. I have owned and ridden at least 4 cx/gl500 and 4 cx/gl650s extensively over the last 30 years. None of them ever showed a temperature gauge reading much over the beginning of the “fat line”, even in moderate summer temps of 80-90 deg f. 500s would go high if left idling. 650s also, and the 650 fans would then switch on at about 7/8 gauge. Something here is substantially less than optimal. Is it destructively hot? I don’t know, but I would not like it at all.
 

·
Super Moderator
Joined
·
24,173 Posts
If the temp is actually that high you will notice that the bike seems to have a pot belly stove under the fuel tank. You can feel the heat.
 

·
Registered
81 CX500c, 83 GL650i
Joined
·
331 Posts
Discussion Starter · #18 ·
So, the bike does have a new 7v regulator from Murray, so I'm guessing it's not that. Maybe I have a loose wire to it or something? I didn't notice my fan coming on yesterday when I pulled into the garage, so maybe that is a contributing factor? Perhaps just to be safe, I'll source a thermostat and oring to rule them out. Anything else I should approach?
 

·
Registered
Joined
·
1,738 Posts
So, the bike does have a new 7v regulator from Murray, so I'm guessing it's not that. Maybe I have a loose wire to it or something? I didn't notice my fan coming on yesterday when I pulled into the garage, so maybe that is a contributing factor? Perhaps just to be safe, I'll source a thermostat and oring to rule them out. Anything else I should approach?
I actually have a different take on this. It sounds like on a typical 650 the fan rarely turns on unless in stop and go traffic. The way you described your ride I would think your fan wouldn’t ever cycle on. At this point I would want to confirm the accuracy of your gauge before tearing into other things. Double check that the 7 volt regulator is wired properly and check the voltage with a multimeter to verify it is putting out 7 volts.
 
1 - 20 of 38 Posts
Top