Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Scared of my Honda CBR250R .. overheating / electrical issue

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Matt GO!!!!!!!, Aug 26, 2008.

  1. Hey everybody.. I currently have a love/hate relationship going with my 1989 Honda CBR250R. It has its good days and bad days. But there is starting to be more bad then good days. I'll get straight to the point.

    Starting with coolant and overheating etc... The bike runs well on a normal day with the temperature on about half.. 3/4... If I take it out to the mountains and give it a bit of stick and its bloody cold up there.. it sits inbetween 3/4 and H. As soon as i stop. Coolant pisses out a little tube and onto the exhaust. This has happened a few times but today it really freaked me out. Went for a ride to Mt Glorious and Mt Nebo, after coming out of them, it was 3/4 temp. Stopped at a set of lights for a minutre or so and i smelt something, looked down and coolant was gushing out of the little pipe onto the exhaust and steam and shit was going everywhere.

    So to all the HondaCBR250R owners.. Have you ever had coolant piss everywhere after a ride??? Is this normal?? It got so hot I wasn't able to start the bike. Waited 5 minutes close to Brisbane CBD around Roma St. Roll started it and went straight home. Stopped at 3 - 4 more lights.. coolant pissed out again and started so smoke and steam on the exhuast.

    Now to the next issue. Electrics. Once a month or every 2 months something dies.. Whether its a voltage regulator or a alternator or a started motor or solenoid or battery. Does anyone have to get this sort of stuff fixed constantly?

    Maybe im paranoid if this keeps up im trading in this thing for a Brand new Honda CBR125R not that i want to. But if this unreliabilty and bullshit keeps up what option do i have?

    Thnx for listening to my rant! :roll: :shock:

    I hope you guys can help me out with some advice.. whether you have owned a CBR250R or not. thanks again in advance.

    From matt
  2. Check your coolant levels when cold. I'll bet you're running way low. Fill the radiator itself, as well as the reservoir up to the recommended level. Let us know how much you have to put in.

    You should keep an eye on the coolant levels every week or so. Pay attention to basic maintenance and your bike should run fine - that is, if you haven't cooked it and rooted the head gasket yet.
  3. Cant really speak for the electricals- apart from its a bike with a bit of age. It could be worth a check over by an auto eleccy

    As for the coolant- it sounds like you have an issue. I'd be going through the system looking for problems- checking thermostat, fans, fan switch, then onto the radiator- external and internal blockages. Dont forget the radiator cap- and the surface the cap seals onto. Then onto waterpump. Sounds to be getting hot enough for the coolant to boil and expand into the spew tank, overflowing when you stop. It sounds as if the cooling system cannot remove the heat of the engine quick enough.

    Consistantly 3/4 temp guage is too high. I know small bikes that will climb that high sitting in traffic on a 35°C day, but not usually when moving.
  4. i have an '88 cbr250r and temp is typically about 1/4 unless i sit still or am stuck in traffic, at which point it goes up to 3/4 temp. As soon as I ride and air starts flowing again over the radiator the temp goes right back down to 1/4

    so no, i've never had coolant piss out anywhere, sorry :/
  5. thanks so much for the quick replys everyone.

    Well i have had it garaged for the past 3-4 hours and its nice and cool so i just took it for a 10 km ride. Not riding fast or taking on any mountains.

    Stopped at 1 set of lights and it hit "H". Im really scared. I have already booked it in for mechanics tomorrow I will tell you all how it goes.

    thnx again for quick replys
  6. Dude FFS why not fill up your coolant? Do you not know how?
  7. I have a cbr250r, um the black ones cant remember the year atm.
    During summer mine would get quite hot but only really sitting in traffic, not while riding, then the fan died and i would turn it off when i knew the light sequence was going to be a long one a i had the same issue wit ridiculous heat and coolant coming out.
    I have found that the coolant would never stay full when i filled it, it would always dump some out of the over flow pipe even durin the winter and would sit on under half and be fine.
    Firstly is your fan workig, you should be able to tell its very loud and two the temp shouldn't be anywhere near that while riding so it sounds like theres no coolant in the radiator or somethin like that.
    And as for the electrics i haven't had a problem with them at all, make sure your fuse box is screwed to the fairing, mine came off once, didnt cause havoc but im sure it would have left unchecked.
  8. one word.. THERMOSTAT!

    (if your mechanical noob, it controls the flow of coolant inside your engine, if yours is old and no longer working it will either be stuck open or closed, this can cause serious overheating issues such as you describe)
  9. Re: Scared of my Honda CBR250R .. overheating / electrical i

    I’m not so alone after all.


    Regarding to your relationship with your 1989 Honda CBR250R, I have the same issue. I currently own the same bike.

    I have the same issue with the temp sitting ¾ if not higher. I have been trying to resolve the issue with little knowledge. The only times I have issues is in traffic. Through the mountains all good as the air flow, is flowing, unlike sitting at the lights.

    The same thing spews coolant through the overflow line.

    What I have discovered is that once I fill up the radiator with coolant, I have notice that when I take off at the lights, it dumps a load of coolant out through the over flow. At this stage this bike is still ok. The next day same thing happens without you knowing. (I had a friend to ride with me to watch) by the second day your radiator level is lower (you wouldn’t think to fill it up everyday). However by the third day, here comes the issue with the temp over heating, boiling and spitting out through the over flow.

    I just don’t get it, mine just dumps if I take off too quick. I got to ride it like a grandpa.

    I have been advised that could be something to do with the pressure of the radiator causing the coolant to spit into the over flow bottle then shooting through the over flow line.

    This is as far as I got. If anyone can help why mine likes to spit out when I take off at the lights before I get to the overheating issue by the third day.

    Feel free to comment.


    Does anyone know where I can get a manual guide free online download?

  10. i would assume that there is either a partial blockage in the cooling system. Liquids expand when they get hot, hence the overflow. Do what everyone else has said, check your levels, check out the rest of it. I'd be particularly concerned with the thermostat. A cheap part but if it goes, It can cause you a whole lot of grief and money loss.
  11. Sounds like a dodgy/weak radiator cap. Hot coolant could be forcing its way past and into the overflow. Are the coolant pipes soft (i.e. not rock-hard) when the engine is hot?

    Replace the radiator cap regardless. If you still have the problem then it could be the head gasket leaking gas into the water jacket. You'll have to take the bike to the mechanic if this is the case.

    As for the electrics, yes they do go sometimes. The Rec/Reg is a particularly flimsy part, especially the one without the fins. Just remember most of those parts are 20 years old. Hopefully they'll last another 20.
  12. Same thing happens on my zx9, except I've got my relief valve pointing upwards, so it shoots great fountains of coolant up in the air. It stops for a while when I bleed the air out of the system. There's a bleed valve somewhere on the left side. Top your coolant up periodically, and tip the bike right over left and right, you'll be surprised how many bubbles you can get out.

    Don't let it run dry, or you'll really munt it. Keep it topped up and don't stress about it.
  13. Thanks for the heads up guys.

    Yesterday I pull the bike apart and found that the radiator was haded. The rubber around the edge was fairly buggered and cracked.

    Replaced, has made a different in the temp, although here in Brisbane hasn’t been all that hot over the last couple of days of rain.

    Let’s hope this has resolved my issue.

  14. over heating cbr

    I think this shows how important regular maintenance is. whenever i buy a used bike or car i always check the thermostat, radiator cap and flush the cooling system. also a visual inspection of hoses and water pump for leaks or even coolant stains (minor leaks).Personally i would have tried to sus the problem out the first time it got hot not waited till it stopped. a thermostat or radiator cap is a lot cheaper than a f@#%&d motor.