Bike dripping water from (overflow?)tube when turned off

[Walkinshaw]

Hi all, newbie here both to motorcycle technical problems and to the rvf400. I bought mine about a week ago, and have taken it for a few short rides. Today I went for a ride for about half an hour, it wasn't too hot out (about 23c) but I spent a bit of it sitting in the hot sun in traffic. Anyway once I got home i heard a dripping and noticed quite a bit of water dripping out of a open tube next to my rear brake under the fairings. i assume this is some sort of overflow tube? i honestly hadn't been checking the temp of the bike when riding but when I switched it back on it only read about 1/4 of the gauge. i would say about 100-200 ml water came out. also when i bought the bike the guy i bought it off topped it right up with water (though he said he generally used a 50/50 mix). could this be a problem with the bike or just because it was sitting in the sun in traffic and had a full water tank?
Cheers

[richyrd5]

yep i would say if its coming out of overflow pipe then its just the heat making it do it.although keep an eye on temp gauge..oh by the way its +4 degrees over here!!.feckin ffrreezzing!!.you lucky sod!!

[CMSMJ1]

the overflow should not be filled right up - it will find it's level and so long as it never runs dry then you'll be right.

23 degrees..lol bastard.

welcome to the site.

[eeikcud]

I hate summer here.... Let's swap weather

[Neosophist]

It shouldnt overflow.

I'd do a proper check of the cooling system.

First, the expansion bottle is supposed to be filled to the Max mark when the bike is cold.

The rad cap is a most likely culprit, if it is weak / the seal is worn or even dirty as the bike heats it it wont hold pressure and let too much water escpae into the rad bottle. You can get them proerply pressure tested.

Also air-leaks / failing water pump can cause similiar issues, less common but worth checking.

Good idea to give it a check and flush / refil the coolant with fresh stuff if its old / looks off colour.

Properly maintained you shouldnt have any issues with cooling, these bikes came from Japan where it regulary knocks on 40c in the summertime and they run without issue.

[Walkinshaw]

Hi guys, so I hadn't ridden this bike much since I made this post as I've been overseas. Anyway came back and had a ride and was still getting the sputtering and leaking from the overflow pipe. So i took off the fairings to check the reservoir tank only to find it empty (!), and a quick check of the radiator was very low as well. How am i losing so much fluid from this system? The bike does not seem to be running particularly hot and in fact the temp gauge has never been above half even sitting in the hot sun. I decided to try and flush the system before refilling with coolant but have struggled to find the drain bolts on the radiator the haynes manual talks about (i am a complete newbie at working on bikes but hoping to get better)..

If the bike is spitting out water from the overflow when the reservoir is basically empty is this likely to be a pressure cap issue as mentioned above? I had a look at the current radiator cap and it does look in somewhat poor condition, the rubber ring is cracked and missing bits and seems to have no spring. Or could it be something worse? There is no white smoke or unusual smell coming from exhaust so hopefully not head gasket.. I just don't understand why there is fluid coming from the over flow pipe when the reservoir is empty..


Thanks guys

[manicguitarist]

If the coolant system is empty then the temp gauge won't move.

Re the drain plugs - the water pump is near your side stand.

M

[Speedy]

Remove the rad cap, then drain the coolant by removing the water pump bolt (blue arrow on pic).
Coolant will shoot out, so be ready to catch it.
Flush the system with water by inserting a garden hose on the rad cap filler neck.
Re-insert the water pump bolt & seal and refill the system with coolant; bleed the system of any air before re-installing the rad cap, by blipping the throttle a few times. Refill the coolant reservoir to the correct level.

[CMSMJ1]

knackered rad cap that is not pressuring the system can cause early fluid loss.

[Walkinshaw]

Thanks guys, I feel like an idiot as I was looking on the wrong side for the water pump. The Haynes manual seemed to be saying it was on the right but maybe they meant facing the bike. Will flush the system and order a new rad cap hopefully sorts it out.