Hot Bike, Cold Radiator (Pegaso)

MahatmaAndhi · Traffic Copper Joined: 10 Jun 2015 Karma :

Hi guys,

The last few days my bike has been getting quite hot, quite quickly. My commute to and from work is around 20 minutes each way, but even a few minutes in, the temperature gauge is right on the red line and the fan has kicked in.
Today, I (tentatively) put my hand on the radiator immediately after getting home and it was cool at the top (tepid at best) and hot at the bottom. At the bottom, I could put my hand on it for a few seconds before the heat made me move away.

I know dick all about bikes and cooling systems generally, but I did have a Corsa way back when that blew a head gasket after running hot for too long. I don't want a repeat of this again.

I have no clue what I am doing, but I can't get to a garage before the weekend, so if there's any diagnostics which I can do myself then please let me know.

Cheers.
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2008 Aprilia Sportcity 250

stickybackbob · Trackday Trickster Joined: 23 Mar 2013 Karma :

Is the radiator full? If so, I'd check that the thermostat was working first, may be slow to open or stuck

MahatmaAndhi · Traffic Copper Joined: 10 Jun 2015 Karma :

The level is a little over Max, like 1cm in the white tank on the side of the bike.
I don't know how to check to see if the thermostat is working. I'm absolutely clueless here.
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2008 Aprilia Sportcity 250

Wonko The Sane · World Chat Champion Joined: 20 Jan 2013 Karma :

Chris45 · Nitrous Nuisance Joined: 23 Oct 2016 Karma :

Water pump and/or thermostat.
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Honda CG125>Suzuki GT185>Honda CB 250N>Suzuki GSX400>Honda CX500B>Kawasaki GPZ305> Kawasaki GPZ550>Kawasaki GPZ500S+BMW 650GS

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

You can test the thermostat by removing it and putting it in simmering water it should open. If it doesn't it need replacing.

Have you got a service manual? Find out where the cooling system bleed screw(s) are and open them to see if coolant comes out.
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

MahatmaAndhi · Traffic Copper Joined: 10 Jun 2015 Karma :

I did have the foresight to take a picture while it was still light outside, so here's a direct link to the image where I think the thermostat is located. However, I have no idea what the thermostat looks like and which of these (if any) is the bleed screw.

I'll try and find a manual online somewhere.

https://i.imgur.com/kIX1zOA.jpg

Edit: Looks like I found a service manual online. I'll have a crack at it tomorrow. If it doesn't blow up on the way to work.
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2008 Aprilia Sportcity 250

P. · Red Rocket Joined: 14 Feb 2008 Karma :

You can just remove thermostat and run without it. If rad gets hot, thats your issue.

I ran my RS with no thermostat, took a while to warm up but aside from that...

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

I wouldn't be keen on having that as a long term solution. Especially through the winter.
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Evil Hans · World Chat Champion Joined: 08 Nov 2015 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

https://marcel2cv.de/wp-content/uploads/peggyreparatur10.jpg

That's the stat housing remove it and put the stat in near boiling water, it should open, if it doesn't that's the problem.

Or as Paddy says remove the stat and run the bike.
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

P. · Red Rocket Joined: 14 Feb 2008 Karma :