I was told 6-7 psi was the correct pressure for a 650, not sure about a 500. I found a 7psi at my local Pep Boys for about 6 dollars. Fits great and no issues.

 

I'm posting in this ancient thread because someone found this incorrect information and it needs correction before someone else is mislead by it.
All CX/GL650 models use the same 0.9 atmosphere (= approx. 13 PSI) rad cap that the CX/GL500 and most other liquid cooled Honda motorcycles and cars of the time used (as well as most other cars, light trucks & motorcycles of other brands).

 

So, does anybody know for sure what psi the GL500 cooling system is supposed to be operating at?

I'm 99% positive I read somewhere on the forum that people were using 13 psi caps on the 500's, but if you say 7 psi is what your 650 calls for I'm inclined to believe that a 500 wouldn't be a whole lot different than a 650 as far as cooling system operating pressure goes.

 

Unless the 0.9 stamped on the cap means 0.9 bar. Assuming that the cap I have is OEM and using the formula of 1 bar equaling about 15 psi I get a little over 13 psi as the rough equivalent. That's figuring I have an OEM cap and my math and the figures I have for conversion are correct.

I'm going to go with a 13 psi cap.

 

The regular size radiator cap from the parts store will work just fine. Double-check that 13lbs is correct, but I think that's it.

 

A Stant 10229 13lb cap works fine on my CX.
The CX manual calls for a 10.7 to 14.9 psi cap.

 

I was going to say I just picked up a Stant 10229 from Fleet Farm. I wanted to not go to a parts store because everyone that works at parts stores immediately assumes you are incompetent or have nefarious intentions for whatever it is you're browsing at. On more than one occasion I've been looking and been asked "well, what's it going on" and if I told them it was for a vintage motorcycle they'd immediately poopoo me and tell me to look elsewhere or that I "can't just put any radiator cap on something", that and the all of the auto parts stores by me (being in the hood) have all their caps and whatnot behind the counter and that's a whole 'nother story in itself.

Anyway the Stant 10228 is 7 psi, the 10229 is 13 psi, the 10230 is 15 and so on.

I also got the Stant because if it's good enough for Ford, GM, and Chrysler to use as OEM, it's good enough for my GL500.

If you have a GL/CX500 and you need a radiator cap I know a Stant 10229 will work.

 

Welcome to the forum, too!

When I was searching for a Thermostat, purchased a 180F Stant and it would not fit in the CX housing. Talking to a "young" man at the front counter and told him I
needed a 52MM 180F Stant thermostat. He found one for me that has "plenty" of clearance in the CX thermostat housing. Not sure how he found it, but it's a
Stant 13958 180F 82C stat that fits & works great!

Here's another place with lots of CX/GL info:

http://cxgl.wikispaces.com/

 

The 13958 is one of the "standard" sized thermostats that the big-3 used in pretty much everything they made from the 50's to the mid 90's and some even later.

I'm amazed with how all of that stuff is just standard parts. Hell, if I get the oil filter adapter I might as well slap a Ford emblem on it. But seriously I like the idea of the adapter, I think I'm going to get one!