CBR250RR heating up

[limmy]

I've noticed that whenever i'm stuck in traffic or in slow traffic i.e 20-30km/h my CBR250RR start heating up. Is this normal?

[FROSTY]

yep--speciallyu this time of year--only worry if it stays in the red zone.

[TwoSeven]

Yep, airflow doesnt work until about 30kph. Might want to make sure that if you have coolant mixed with the water in your rad, that it doesnt have anti-freeze in it. Dont know why they insist on puting anti-freeze in everything here, but it makes running temps worse in the summer.


Also if it goes into the red zone, check to see if the fan is running.

[limmy]

thanks for the tips guys. i'll have to check the radiator and stuff. i'm new to bikes so it should be fun trying to work it out.

[XTC]

thanks for the tips guys. i'll have to check the radiator and stuff. i'm new to bikes so it should be fun trying to work it out.
Just ask lotsa questions in here and you'll soon sus it out....

[Sniper]

Mines doing it too mate. Oh yea, if you tend to thrash the bike a wee bit, just double check your thermo switch to make sure it hasnt "unclipped"

[Monsterbishi]

On a curious related note, my MC19's fan didn't work until we found out that we had the wrong size battery in the bike, new battery, fan works now...

[bugjuice]

My CBR used to be a bit of a dog in traffic. One of the previous owners had some wiring done, and they forgot to reroute the fan, so it wasn't on. I was sat on a hot day in traffic, glanced down to see the needle well into the red. Crapping myself, I looked back to see vapour coming out of the pipe.. Packing myself, I filtered thru traffic, then heading in the other direction to get the airflowing thru. The temp got back to normal and didn't appear to do much lasting damage (doesn't matter now, cos the bike is dead anyway). I fitted a switch to the fan so I could switch it on manually myself, that helped a heap. The CBRs were never too great at the cooling thing. Even hacking mine round Puke used to cause it to heat up, but general riding wasn't a problem..

Next time you see it getting warm again (about 2/3 up the gauge, the fan should kick in around then), if you can, kill the engine at the cut off switch (not the ignition key) and stick your head down the left side of the bike, see if you can hear/see the fan spinning. Just to be sure it's actually working. I didn't know my fan wasn't even connected until I pulled it all apart to see what was going on.. And that was about 8-9 months after I got it..

Just bear it in mind when it does get hot and pull over to 10 mins if you see it cooking up good, else make sure you keep the air flowing thru when and where you can.. My bro's CBR was the same too (that's dead as well - both bikes his doing, not mine..)

[merv]

Might want to make sure that if you have coolant mixed with the water in your rad, that it doesnt have anti-freeze in it. Dont know why they insist on puting anti-freeze in everything here, but it makes running temps worse in the summer.

Anti freeze is usually ethylene glycol which also acts as a coolant as far as I know so it shouldn't be a problem. Most Jap stuff is made to run with a 50/50 brew of water/glycol and the coolant/antifreeze acts as a corrosion inhibitior too, seeing our pride and joys are just about all aluminium these days.

[F5 Dave]

Yep, airflow doesnt work until about 30kph. Might want to make sure that if you have coolant mixed with the water in your rad, that it doesnt have anti-freeze in it. Dont know why they insist on puting anti-freeze in everything here, but it makes running temps worse in the summer.


Also if it goes into the red zone, check to see if the fan is running.

'Anti freeze' has 2 functions. The first a bit redundant here in NZ agreed, unless you go to the Brass or Cold Kiwi. Water expands when frozen so may break the cases. Though you can get plain non antifreeze inhibitor.

The more important function is to prevent corrosion esp in a bike engine which is all ally & not much meat to damage before a leak will cause damage.

Further corrosion will create a barrier hindering heat transfer.

This should really be replaced every couple of years as it does degrade which won’t help cooling either. Pretty easy job. Good idea to remove the pipe to the thermostat if you can get to it & remove it (temporarily of course) so you can flush the system both directions.

Nobody does of course so it ends up like sludge (like brake fluid does).

[limmy]

yea. should probably check the radiator. i've only had the bike for bout 3 weeks but haven't actually check any of these things. Initially i thought that the fan wasn't working since i never heard it or felt any air flow but if it only comes on when the temp needle is 3/4 to the red then i don't think it would have ever come on when i was riding. so far the most the temp has ever got to is just a bit over half way.

[TwoSeven]

Half way is normal.

I cant remember what my temp guage looked like on my old 250, but when the needle is in the big square on the left, the bike is cold and the engine wont work properly with the plugs being likely to cold foul (thats where the plug gets a clear residue layer that insulates it and stops it working).

When it gets to the beginning of the white line, the bike is warmed up, but at minimum temp (84C). Cibbies like to run at that temp, but they'll cope with higher temps - at this point the plugs will start to be at the temp where they self clean, so fouling is reduced.

The fan doesnt come on til 3/4 - its mainly there to stop the water boiling in the rad, while the bike is stationary its not there to aid cooling in the engine. Once the bike starts moving above 20kph , the fan will have no effect, even if its on.

[dviflx]

ok.. heres my problem..

i thought i woul be a genius and service my bike.. changed oil filter, air filter, spark plugs (which were a pain) etc etc..everything was good until i came to the coolant, and i was scratching my head a little.

i really didnt know what i was doing when it came to draining the coolant. i ended up undoing one of the bolts that goes into the cap on the left hand side (near gear lever) and i noticed some coolant flowing out.. but then it stopped.. i squeezed the main rad hose, then it flowed out again.. so i continued to do this until there was nothing coming out.. but then realised that all i did was pump the coolant that was in the top end of the cooling system.. nothing had came from the reservoir.. as you can imagine i had a bit of a problem.. i think syphened the coolant out of the reservoir till it was empty.. did the side cap up, then refilled the reservoir..

for some reason the bike is over heating extremely.. its unrideable until i get this problem fixed.. can anyone help me? i need to know where the nipple next to or on the thermostat is and how to drain it properly, and refill it properly..

i'm just about to sell this bike, everything is perfect except this so i really need to fix this problem, if anyone can help, it would be much appreciated.. thanks,

Tim

[F5 Dave]

Hi & welcome, usually best to start a new thread than resurrect a really old one, but no drama.

Not familiar with this bike, but obviously there is some other drain.
Try having a look at a parts diagram for your bike to see if you have missed any drain/bleed screws. Should be able to google a diagram.

Some bikes you just have to remove a hose at the lowest point & obviously take off the rad cap to help it drain.

Most systems should be self bleeding, small 2 strokes often have bleed screws on the top of the barrel, but this shouldn't apply.

should be able to run the hose through both directions with a hose removed, for a good flush if coolant is too crappy but may need remove thermostat.

[The Pastor]

ok.. heres my problem..
i think syphened the coolant out of the reservoir till it was empty.. did the side cap up, then refilled the reservoir..



Tim

Err isnt coolant really poinsionus? Maybe thats why he only has 1 post....

[Sketchy_Racer]

what you did was take the coolant drain screw out, but let me guess, you didnt undo the Rad cap when you were trying to drain it? Nope

by squeezing the hose you pumped the coolant out, but by only refilling the resivor, the rad is still empty. fill the radioator back up. The cap is under the tank.

Good luck

[Indiana_Jones]

when riding mine normally, and stopping at the lights, the heat needle seems to stay at just over 1/2 way.

-Indy

[slinky]

I've noticed that whenever i'm stuck in traffic or in slow traffic i.e 20-30km/h my CBR250RR start heating up. Is this normal?

yeh mate, mine did this aye. gave me a frieght the first time.
but i guess you noticed as soon as you start moving it drops pretty quick

[Indiana_Jones]

yeh mate, mine did this aye. gave me a frieght the first time.
but i guess you noticed as soon as you start moving it drops pretty quick

lol same, Spooked me abit, but it makes sense. Engine is hot, but is being cooled by air pass over it. Stop, the air stops cooling, heat goes up abit. But aslong as your fan works and u have coolent in your radiator, you should be safe :)

-Indy

[Indiana_Jones]

sorry to dig this up, but where does the fan kick in, or should do. I remember the 1st day i got it, the fan was on, but i havn't seen it on since. Also what is normal temp for going around town? after I got off the m-way this nippy morning it was on the 'M'

cheers

-Indy

[more_fasterer]

From my experience, the fan kicked in once the temp needle was only about 2mm from heading off the end of the "normal" line.

Considering the needle would sit at about 1/3 of the way up when moving, it was a bit unnerving to see the needle heading up past 2/3. But once the fan kicked in the gauge only went down.

[t3mp0r4ry nzr]

trackdays in 30 degree heat had my 250 very hot! I have since used "CoolAid" which is distributed by forbes and davies and the temps have been alot lower. Its a non gycol based product for racing, has no anti freeze properties but has anti rusting properties. very good stuff and recommended