Running without a thermostat YAM R1

cyberglass · World Chat Champion Joined: 28 Jun 2005 Karma :

Been having a cooling system problem with the r1 where the coolant fills the expansion tank then pours out the overflow.

Ruled out Head gasket.
Pumps working fine.

Ideas are
Thermostat tested in boiling water and it seems to open but dont have a thermometer to test at 85C

Radiator cap

So a few mates have said to cut the thermostat center out and run it like that as it doesnt really need one anyway.
Went to the bike shop and he said that's what he would do to.

But it just feels wrong why would it be there if it didn't need it. ??

So what would you guys do replace it with a new one or cut it and run without.
____________________
DL650 Vstrom 2004
DRZ400S 2003
Yamaha R1 2005

Cigaro · World Chat Champion Joined: 28 Mar 2007 Karma :

You can run it without a thermostat to test whether that is the problem.

Just means the engine will take longer to warm up. You may use more fuel too.

In the long term I'd get it replaced.

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

Run it once with no thermostat to see if it makes any difference (it won't). Then try another rad cap, there is a very small chance it's failed - borrow one of a japanese car/bike they are all the same.

If it's still doing it, then back to the head gasket I'm afraid.

f.

cyberglass · World Chat Champion Joined: 28 Jun 2005 Karma :

well ran it with the strom radiator cap and a cut up thermostat and........ it ran perfect Mr. Green

Now to dust of my wallet and order new ones Thumbs Up

Knew it wouldn't be the head ive done that many on rovers ive got a head gasket sixth sense HAHA

Thanks for your input guys much apreciated Thumbs Up

____________________
DL650 Vstrom 2004
DRZ400S 2003
Yamaha R1 2005

Cigaro · World Chat Champion Joined: 28 Mar 2007 Karma :

One thing to remember is that without a 'stat, the motor will take a long time (if ever) to get up to temperature. Therefore it may be behaving itself simply by virtue of the fact that there is no pressure in the cooling system.

If you replace it and it does it again, you know your problem lies elsewhere.

cyberglass · World Chat Champion Joined: 28 Jun 2005 Karma :

I covered the rad with some card in an attempt to compensate for the extra cooling. and took it for a spin.

It acted as it should in traffic and when i left it for 10 mins got up to 104C on the gauge then the fan kicked in without boiling over.

Didn't even make it to 90 before dumping the coolant with the stat and other rad cap in.

So touch wood its now ok.
____________________
DL650 Vstrom 2004
DRZ400S 2003
Yamaha R1 2005