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View Full Version : help with cbr900 cooling system



13-12-2010, 12:23 AM
Hey guys, i was hoping someone could chime in with some advice on the (according to the manual) "coolant air bleed hose" on my 94 cbr 900.

I am doing a fighter and have alreay chopped some stuff.

What I mean is the small hose that goes from the top of the rad (under the overflow hose and over the main hose) to the top of the thermostat housing. I had a look at it and it seemed to take coolant to and from the same areas a the main hose and since I wanted to tidy this hose I modified the rad and thermo housing to eliminate this small line. Have I fuc#ed up? To me the coolant should still circulate in the same way it did because this small line was so close to te main hose flow.
I can't see any problems but I wanted to be sure it won't build air in the system somehow or something like that.
Any insight would be appreciated.

Cheers

Dan

scotty
13-12-2010, 06:06 AM
hi dan, if you are after an answer mate firstly you should head ova the welcome section and intro yourself. The only person that is that easy is blowie mate

13-12-2010, 10:30 AM
Hey Scotty, I have done this previosly but it was a while ago. Do you think I still need to? And I have posted here before but just notices my post count has reset. huh. I guess my bike has sat in the garage for too long:)

scotty
13-12-2010, 10:36 AM
quote:Originally posted by danulmer18

Hey Scotty, I have done this previosly but it was a while ago. Do you think I still need to? And I have posted here before but just notices my post count has reset. huh. I guess my bike has sat in the garage for too long:)
like i said mate if u really wont answers to your questions u should do an intro.

RevHead
14-12-2010, 07:25 AM
hey fella welcome anyway,,with that little hose you chopped out its a bypass hose i know it looked as thought it did nothing but its a must,,finding another thermostat housing shouldnt be to hard ,enjoy

EXBEN
14-12-2010, 08:03 AM
It's actually an air bleed, I've deleted these many times without creating issues, sometimes it can make the cooling system harder to bleed, what you can do is leave a short hose on the thermostat housing then when filling the bike with coolant let the air out the hose then plug it & leave it under the tank. Or just see how you go as is.

14-12-2010, 11:34 AM
Thanks guys, much appreciated. So as long as I get the air out on filling it shoud be ok? Just to explain, the pipe outlet from the thermo housing originally went down from the housing causing the hose to go down then under the rad then back up to the top and the connection was by the filler cap.(classic cbr900) I have moved the connection of the main line on the rad to the other side of the top which allows the hose to run higher than the thermo housing the whole way.(inside the frame above the head) I changed the pipe outlet on the thermo housing so it now faces up. Am i right in saying that the bleed line was necessary when the coolant line dropped below the thermo housing and head (the bleed line ran up where I now have the main one) Now that I have the main hose above the head the whole way I should have no air bubbles when filling?

EXBEN
14-12-2010, 09:46 PM
Suck it n see....

14-12-2010, 11:18 PM
How will I know if there is a signifigant air bubble in the system? Watch the temp gauge?

el sammo
16-12-2010, 07:30 PM
you can cheat a little bit by getting the front of the bike up higher as you bleed it too like get some mates to lift the front wheel up on a 60L drum while you run it with the rad cap off

Shadowzone
16-12-2010, 07:46 PM
Just a thought but Volvo trucks have a valve on the bottom of the cooling system and fill from the bottom.

Has anyone ever thought of trying this? It would mean you'd need a hose fitting to clip it on and a pump but it would be doable and save a lot of hassle when changing coolant.

I'm sure Mr Exben could possibly come up with something to screw in somewhere and a hose attachment to match?

17-12-2010, 01:52 PM
Cheers guys, I like both those ideas. I will try filling it on an incline first.