Welcome back - please login below. New here? It's quick & easy to register!

Register Log in
  • This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

CB650F Coolant change after repair

Goblin

2019
CB650R ABS
Messages
124
Likes
80
Thread starter #1
Need some advice with a coolant change. I helped a friend with his CB650F (2016) that had a coolant leak coming from the thermostat case. So I replaced the rubber O-ring and tried to fill her up with fresh coolant.
D2B0CD4A-BAE5-4916-840E-663CE2828DD6.png
I know about air pockets that can trapped in the system, so I gently put the first liter coolant in and gave the system time to let the air escape. Following the service manual (bleeding the radiator bleed bolt) tried to fill the second liter coolant in, but the radiator was full after I put in the next half liter. So I started the bike to bleed the system, but the coolant is coming straight out of the radiator. Long story short, I can’t get more than a liter coolant in her (I must overlooked something). This is not the first coolant change I did in my life but this bike is giving me a headache ☹️
 

miweber929

2014
CBR650F
650F Alumnus
Staff
Messages
2,099
Likes
1,209
Location
Woodbury, MN
#2
I don't have a service manual in front of me but is there a bleed screw on the front of the engine block? Usually that will get stuff flowing. Sounds like you have a classic air lock behind the thermostat. I’d try to find something on the other side to get things flowing; I usually tip the bike from side to side and pinch hoses which sometimes gets them flowing.

Good luck!!!!
 

Goblin

2019
CB650R ABS
Messages
124
Likes
80
Thread starter #4
There is only a bleed screw on the side of the radiator. I did tip the bike from side to side and pinch the hoses. Yeah I think I have a air lock behind the thermostat. I did a full drain and tried it again but with the same result, what the heck am I missing 🧐 (a coolant change isn’t rocket science)
141CE95D-899F-4751-873F-643FDE3ECF58.jpeg
 

Goblin

2019
CB650R ABS
Messages
124
Likes
80
Thread starter #5
Update on the coolant change for the CB650F. For some reason the air wouldn’t escape from the system doing it the traditional way. So I used the airlift way, pulling a vacuum in the system With the vacuum purge tool. All is fine now, all coolant is in and the bike is running again 👍