Radiator Cap Alternative

[Claviger]

Having a need for a radiator cap, I went to our local KTM dealer knowing our radiator is manufactured by KTM.

Handed them the stock cap and got this, which fits like a glove:

PS: The interesting part is that it opens the door for 1.6, 1.8, and 2.0 bar caps. It fits many KTMs but for sure it fits the 2010-2012 990 Adventure. It’s also cheaper than the Triumph part!

 

[joesoap]

Have you run the bike through a heat/cool cycle...will the new cap siphon the coolant back from the catch tank into the rad. I had a spell where my rad cap was,nt holding pressure and experimenting with a few until i found a high pressure that held but also opened to siphon back when it did blow off coolant. I wish triumph just thought out a few things more closely when building there bikes as my tiger explorer does the same and ive had to find a high pressure cap for that too

 

[Claviger]

That’s something I don’t understand actually. In a pressure relief system how would it fill back up from the reservoir? As soon as pressure drops it’ll seal the cap and the reservoir can’t drain back.

If the pressure cap were on the reservoir Id get that but from how I see our systems, it’s not a “reservoir” but instead a overflow tank.

 

[joesoap]

That’s something I don’t understand actually. In a pressure relief system how would it fill back up from the reservoir? As soon as pressure drops it’ll seal the cap and the reservoir can’t drain back.

If the pressure cap were on the reservoir Id get that but from how I see our systems, it’s not a “reservoir” but instead a overflow tank.

Yea it is magical init...its when a hot turns to cold it creates a vacuum and enables the rubber under the cap to lift and draw coolant from the "expansion/catch tank" and return the rad to a full state and atmospheric pressure is returned..clever idea if you have a fully functional cap.

 

[barbagris]

Have you run the bike through a heat/cool cycle...will the new cap siphon the coolant back from the catch tank into the rad. I had a spell where my rad cap was,nt holding pressure and experimenting with a few until i found a high pressure that held but also opened to siphon back when it did blow off coolant. I wish triumph just thought out a few things more closely when building there bikes as my tiger explorer does the same and ive had to find a high pressure cap for that too

I have exactly the same issue. Started recently. @Claviger - Much obliged - I shall order one of those.

Edited - Just seen a recommendation for teh KTM 59035009000 which looks EXACTLY like teh one on teh R3. Cheaper still.

 

[Claviger]

Yea it is magical init...its when a hot turns to cold it creates a vacuum and enables the rubber under the cap to lift and draw coolant from the "expansion/catch tank" and return the rad to a full state and atmospheric pressure is returned..clever idea if you have a fully functional cap.

I'll have to take a look later, seems like a stupid system to me, has to be a better answer than relying on a rubber washer that's exposed to drastic temperature swings to allow drain back. Edit: Ah, I see it now, the vacuum allows the center area to separate creating flow back in.

I have exactly the same issue. Started recently. @Claviger - Much obliged - I shall order one of those.

Edited - Just seen a recommendation for teh KTM 59035009000 which looks EXACTLY like teh one on teh R3. Cheaper still.

I like the one I found because its a 1.4 bar not a 1.1 bar, but a 1.1 at a cheaper price is a win! The extra pressure, I'm hoping, will keep the bike from throwing quite as much fluid out of the radiator into the reservoir whilst simultaneously allowing for a higher heat capacity in the cooling loop. I may go to a 2 bar cap, not sure yet.

 

[TURBO200R4]

just saying
the more pressure the cap holds in the greater the pressure in the tank i know i do not want to exceed the pressure of the old cap, the radiators r kind of a lot of $
now it looks like the seal on the original cap was kind of buggered
i guess what i would want on hi performance would be a little bigger catch tank.

 

[Claviger]

Do what your comfortable with of course, but, higher pressure caps are a common addition to high performance adventure and dirt bikes when used in the dessert.

That said, I’ll be sticking with the 1.4 for a while to test. Higher pressure increases the thermal load the coolant can dissipate.

 

[Bedifferent]

Other than the pressure, does it have a locking screw?

 

[Claviger]

Nope! The locking screw is over engineering and finding a fix needing a problem at its finest imho.