250-500cc 09wr300 overheats

I just got back from a ride in the mts and my bike is totally overheating. Rode these trails lots of times never an issue. I am losing fluid out the overflow (I think) and there is no noticeable water in my transmission. Bke got extremely hot but I had to ride it out.

When I got home I had maybe a 1/4 cup of fluid!

I have recently changed the jetting a little but I was losing rad fluid before I did this.

I also replaced the top o ring and gasket on top of motor thinking that was the issue.

Could I just not be getting enough fluid in when I fill it-am I that stupid?

I have seen some stuff about burping the rad and thought I had done that. I'm just really at a loss here and would welcome any advice.

Also if you know what temps do your wr's run at?

Airlock or bad pump.

Or a bad cap??

Going too slow

The radiators have recently been repaired (bad wreck last year) so I hope that's not the issue.I am hoping its a cap issue or an air lock but not sure how to get that air lock out.

I do like the idea of going faster but I know how slow I am and I think I'm stuck with that speed.

I have an '09 250. I rarely loose coolant. Only when i'm creeping along while revving for prolonged periods which I try to avoid.

What are you using for coolant? I run straight distilled water + water wetter.

As far as burping I just fill them slightly above the fins then rock the bike gently from side to side and top it off. Then I go on a short ride and check it again.

My buddy also has an '09 who did have overheating problems when getting stuck on a rock or root or whatever. He got some of the oversized chinese rads on ebay and says they work better.

If your overheating problems started after having the rads repaired I would say your answer's there somewhere. For example, did the repairer blank the rads to stop dirt ingress and you have fitted a pipe unknowingly? or, has the repair itself caused a restriction. Otherwise, it sounds like you've checked the easy stuff so i would be looking at the pump itself.

I ordered a new cap last night. Really hoping that the cap I had on there was defective or not strong enough. Headed out of town for a few days but I will get busy when I get back and let everyone know what happens.

This bike never overheated until I switched out clutch perches and got the clutch adjustment wrong and the drag made it burp fluid at the 2012 golden spike (thats my theory anyways). Do the caps fatigue? I am wondering if once it burps fluid does that spring get weaker?

Anyways I broke my wrist pretty badly on my next ride and also mashed both radiators. I was able to ride again last winter but outside temps were cooler and winter riding where I live is desert riding so higher speeds and cooling issues were not so obvious.

Thanks for the help.

If you are running a screen type spark arrestor, make sure that it is clean.

I tried earlier this spring to get the end cap off but was unsuccessful. Weird because the stock muffler on my cr125 was a piece of cake. I will look again at that.

Have the new stronger cap on and am going to run water wetter for my ride tomorrow. It's really hot here-100 in the valley so it will still be hot in the mts.

I did notice that I had a very small drip occasionally at the bottom of the right radiator where the hose attaches. I am wondering if that nipple is slightly out of round? I checked the hose and I can't see a crack in it.

Oh well, I'll see how it goes tomorrow.

By the way any of you that have temp sensors what is the operating range for your bikes?