CX500 GL500 650 Global

sheppola wrote:

LRCXed wrote:What were all the symptoms in the beginning that made you go to the thermostat? You said it was in the STOPPED IDLING post! Was it due to heat? I didn't get to read that post on Choppers!

IIRC he had been for a ride and it started hitting the redline.Came home and it was still hitting it.When he checked the coolant flow there was none across the Radiator top fins so 1st stop change Themostat.This hasn't helped as per above so I know suspect the water pump/impellor.Could be a blocked side cooling tube but i've never heard of that on one of these but it's possible.Could also be a blocked Rad come to think of it.If it is then the old 50/50 white vinegar flush and hose pipe up the Rad(Ooooher)

Well you got the story mixed up with a previous woe of mine, but now that you mention it, they're probably related. I did the vinegar rinse but not the hose flush; should I just blast away with the garden hose, up into the rad drain hole? Do you think this might dislodge some horrendous blockage which could cause the behavior of having no coolant flowing?

If we can fix the cooling I'd leave the Triple pass til later.Also you don't have to remove the metal part of the Mech seal from the rear case anyway,

http://www.geocities.com/sheppola/cx500/mechseal.htm

Ok, I read the quote.
Now, is this a bike that you just started working on and it's been sitting for a long time before you got it, or have you been riding it for a while and all of a sudden it happened?

Reason for asking is that when I got my 78, it had sat for years. I tried to flush it and thought I got it all out and clean. I didn't. When I started taking the motor apart for other reasons, I found ALL the coolant passages were blocked up with what turned out to be crystallized coolant. Someone had mixed different types of coolant in it and they did not agree with each other. A common problem even with car engines. I ended up having to take the heads off and all the cooling system to scrape out all the blockage. Around each cylinder and up inside each head too, and clean each passage before it was ready to pass coolant again. Lots of scraping and brushing! The strange part was that it never effected the radiator, just the inside of the motor.

I would pull one of the coolant elbows off one of the heads and stick a water hose to the bottom radiator inlet (towards the motor) to ensure you have good flow. You might have a blockage in it just as Shep suggested at first. Pull the small hose off the top of the water pump cover as well and see if it flows too.

Let us know what you find!

Silly question but are you sure it's boiling? Have you checked the voltage out of the 7v regulator? That can make the guage read high. (ignore for 650, they have 12v clocks)

Dave.

This might be an issue, it was for me. Upon reassembly, somewhere in the cooling system I got an air lock. Everything worked fine. Thermostat checked out ok. Still no fluid flowing. (Dangerous procedure follows) I allowed the engine to overheat to the point that the gauge read really high (about 3/4 to full hot range). Then, suitably protected with lots of towels, and gloves, I undid the radiator cap. It blew up spewing fluid like old faithful. Once it settled down, I then topped up the radiator at the rad cap with fluid. I checked the reserve bottle - it was still at an acceptable level, and started it up again. This time, the temperature rose up to normal and nailed it there.

I figure by doing this I blew the air lock through the system which was then back-filled with new fluid. I don't recommend this way - I did suffer mild burn on my hand, but the air lock is gone and hasn't reappeared.