Radiator Cap Rating / Best Coolant?

[twowheels]

What's the highest rating you have used on your 450?

CV4 has a 2.1 bar/31 psi cap I was thinking of trying, combined with a better coolant.

[stainlesscycle]

i'm assuming there's a 1.2 on there now? 2.1 is a lot more pressure...i'm sure the system can handle it, but if you're getting hot enough to get to 2.1 there's probably another issue? i dunno 4t gg at all - but i know my husky te450 would blow the cap until i went to 1.6 and then it was fine.. 2.1 is almost double the pressure.. i'd be worried about head gaskets...

[Nick]

I used stock cap from KTM and engine ice and no more issues.

[Qui-gon]

My 06 has a 1.4 on it which I believe is standard? Is it overheating or overfilled? If you try and fill it to much it will come out until it finds it's own level. Does it have a fan and does it come on? Is it connected with the hanging idle problem?

[twowheels]

The bike has a reworked radiator - the filler neck was modified to accept a Japanese style cap and has a 1.6 bar Outlaw Racing piece fitted now. Whether that cap is functional to rated pressure is not known.

The idle issue has been resolved - thanks Nick - with a fuel trim adjustment and throttle cam stop adjustment.

The fan checks out OK with the Technoresearch tool and comes on when the bike is idling, but its still spitting fluid, even before the expansion tank fills.

[twowheels]

Originally Posted by Qui-gon

My 06 has a 1.4 on it which I believe is standard? Is it overheating or overfilled? If you try and fill it to much it will come out until it finds it's own level. Does it have a fan and does it come on? Is it connected with the hanging idle problem?

Whereabouts did your radiator "find its level"? Cold, can you see fluid when you remove the cap?Wouldn't it make sense that the expansion tank would fill first before the cap blew off pressure?

[blitz11]

Originally Posted by twowheels

The bike has a reworked radiator - the filler neck was modified to accept a Japanese style cap and has a 1.6 bar Outlaw Racing piece fitted now. Whether that cap is functional to rated pressure is not known.

Do we know the quality of the "reworked radiator?" If the cap is crap, it's gonna' spew. If the radiator rework is crap, it's gonna' spew.

Can you hit the Radiator with an IR Thermometer, and see the temp at which it spews? That might tell you something about the cap and/or radiator.

[twowheels]

Originally Posted by blitz11

Do we know the quality of the "reworked radiator?" If the cap is crap, it's gonna' spew. If the radiator rework is crap, it's gonna' spew.

Can you hit the Radiator with an IR Thermometer, and see the temp at which it spews? That might tell you something about the cap and/or radiator.

Supposedly the bike didn't leak coolant before (but then again its been awhile since it ran). I'll hook the TR tool up to it again and record the temp when it starts to spit.

[Qui-gon]

The expansion tank on these seems a little weird compared to most types. Mine is almost empty at startup then fills up to about 1/3 to a 1/2 as it gets warmer. When stone cold there is about 1/2 inch below the rad cap with the bike vertical. Tried topping it off before but it just spits it out down to that level and stops. There was a problem with shitty welds on the rad filler neck preventing the cap sealing on some years, but the rework should have taken that out of the reckoning.
When you check the ecu indicated temp, you may want to verify the water temp with a thermometer just to make sure the sensor is in range
How much did you have to alter the fuel trim and which way?

[twowheels]

Originally Posted by Qui-gon

The expansion tank on these seems a little weird compared to most types. Mine is almost empty at startup then fills up to about 1/3 to a 1/2 as it gets warmer. When stone cold there is about 1/2 inch below the rad cap with the bike vertical. Tried topping it off before but it just spits it out down to that level and stops. There was a problem with shitty welds on the rad filler neck preventing the cap sealing on some years, but the rework should have taken that out of the reckoning.
When you check the ecu indicated temp, you may want to verify the water temp with a thermometer just to make sure the sensor is in range
How much did you have to alter the fuel trim and which way?

I'll have a go at measuring temps tomorrow. I adjusted the fuel trim from -10% to 16%, then dialed out a rich bog with the air screw under the body. Backed the throttle cam stop screw out until "closed" was 5.2 (from 8.6). Starts, idles (~1675-1700rpm) and runs like a champ.

Checked the rad below the filler and there is fluid covering the tops of the coils. I'll mount a catch bottle and see if it's still spitting ...