I completely overlooked the cooling system on my water-cooled CBR150R, until yesterday. It started to lose water and the temp gauge started reading in the red (you do have a temp guage, don't you?). The mechanic found that the filler cap, which contains the thinga-ma-jig that opens and closes the cooling system, had died. One or two gaskets or the spring had died. About 350 baht to replace, but boyfriend ran all around town to find a Honda dealer with one in stock.

Come to think of it, the coolant (anti-freeze) should be replaced more often than every five years (we had replaced it once before, and it now has 57K km and five years). And does it really need anti-freeze in a hot climate? Probably so, since ethylene glycol also raises the boiling temperature to ensure safer system.

What do you call that device in a cooling system that opens and closes the water passages as the temp rises and lowers? It is not just a thermostat, is it?

With all the new water-cooled engines now, this is not just for CBR's and bigger bikes.

HI

It is the thermostat

you should change cooling water more often, and use the right stuff, i use Karshine coolant, anti rust, anti boil, and it will lubricant your water pump and thermostat

So go and do it now

Forgot: www.karshine.com

Edited May 8, 200818 yr by HDRIDER

Most likely it is a "Wax Pellet" thermostat. That's what's used in most internal combustion engines. As far as the coolant is concerned use it. That's what the manufacturer calls for. My question is; does your cooling fan work pretty well? I haven't ever really noticed when mine kicks on.

daveboo, I guess my cooling fan works well, and quietly. I have never heard it. OTOH, my 1982 Yamaha Vision 550, a great bike, would leave the fan running for a minute or two if the engine was hot, after you turned off the engine. I doubt the CBR150R fan stays on.

Which scooters in Thailand are water-cooled? I think my partner's Yamaha X1R is.

PB, get the radiator matrix cleaned as well, this is where the air flows through the radiator to cool the coolant, Can be done with low pressure jet water wash or an airline, Best done from engine side outwards, Try it and watch the crap [road dirt flies ect ] come out, Cheers, Lickey.