Heeellllpp!!

ok, i've not had my bike long but this problem is slowely getting worse..
when i got my vfr it didnt have a water expansion tank on it because the lad before was gona get it ready for a track day. it kept getting really hot quick and the temp gauge was really unstable.
i replaced the water bottle and this seemed to help initially.

but now the bike runs fine for about 10-15miles (temp gauge reads normal) then suddenly I feel the bike get VERY hot and as soon as i slow down the temp gauge reads max heat. it goes down a tiny bit when i'm moving again but its not good.
it seems odd that the temp goes up so suddenly, not gradual.... any ideas???
thanks

It could be several things, did you bleed the system when you fitted the expansion tank? You might have an air lock.
The next thing to try is a new radiator cap as they can be problematic. What condition are your radiators in? They could be on their way out.


I just did a search and found this thread. There's some good pointers/things to check in there.

I'll take a look at the thread, thank u sooo much!
i did start looking to see if there was any similar problems posted on the forum but all the technical terms scared me! lol
first stop...i'll check the rad.

thank you!!!

When I got my NC, the temp sensor was faulty and would read full scale deflection as soon as it got hot.
I stuck my sensor in a warm cup of tea (prolly about 70deg) and it went off the scale.

think i better get my haynes out...
looks like it could be lots of little things
urgh...why cant ya put your bike away in the garage and it fix itself!! lol

btw... what a waste of a cuppa! lol

had this problem, was the rad cap.

does it climb into the red or past 3/4 of the way and not come down ?
if so i would check the water pump is actually pumping
remove the cap, and when you rev the bike you should see the level drop / rise slightly and see water moving slightly (more of a vibration in the coolant)
if its still and nothing happening then i bet your water pump has broken off its locating pin

is the fan working ? also cleaning the bottom radiator on these bikes makes a huge improvement to the running temp as through time the fins get clogged with road dirt thrown up from the front wheel and it bakes into the air channels on the rad . its a time consuming job soaking the the rad for a few days then clearing the channels and straightening out bent fins etc, but does make a noticable difference if all the rest of the above has been checked .

if you decide to take the radiator off, you can check it by holding it up and see how much daylight is showing through it . the top radiators i find tend to get insect debris and are slightly easier to clean than the lower which takes the brunt off road tar small bits of grit etc between the fins . its a pain in the arse job but worth doing if you have time and patience. if not try geoff33 on here and he might have a decent rad for sale.

CRM ...yes that is what's happening so that could be it, that's something we haven't thought to try.
Hopefully we'll get a good few hours on Saturday to try these things, got a long list of stuff to have a go at.
And if none of it works....at least I'm gonna have an awesome knowledge of the cooling system by the time I'm done!! Lol
I really appreciate all the advice, it's been sooo helpful.
I wouldn't have had a clue where to start without all your help :)
I'll get back to u at the weekend...
<crosses fingers in hope>
x