Overheating 2009
 

Hey guys!

Lurker here, i’d hate to be that guy that posts 1 thread asking for help and then disappears so I’ll do my best to hang around :p (I even uploaded a custom avatar!)

I’ve got an 09 Klx250 big bore. I’m stumped because it went into a mud hole last month and after I got it out and got it running again it’s been overheating on me. Like spilling its guts overheating and it usually happens within 30 minutes or so of riding whether I’m going fast or not. I checked the thermostat that was good, flushed the coolant and cleaned the radiator real good of mud and dirt. The fan hasn’t been working but the fan rarely kicks on on these anyways I thought so I’d prefer the “just go faster technique”

I noticed when I poured in the new coolant and turned the bike on that it wasn’t really moving in there. I felt the hoses by the impeller and they are real squishy like nothing is being pumped through. I took off the impeller cover and fired the bike up and it does spin.. I know this doesn’t always mean they are working properly.. any ideas? I’m stumped and my local mechanic doesn’t even want to figure it out either. You fine internet folks are really my only hope I miss my bike :(

You may have an 'air' lock. Imagine 3 buckets filled with water with hoses between them. If air gets in one of the hoses, the water will not flow.
Disconnect one of the hoses to the pump out of the bottom of the rad. fill it with fluid till it comes out the other hose. Connect to the rad and do something siimilar to make sure both rad have fluid full and are connected without air in the pipes. start the bike, let it run till the fluid starts flowing (making sure the thermo is working) and everything is topped off.
If your blowing fluid and your fan isn't on, that could be your problem.

thanks for the advice! I was reading on other bikes that there sometimes is a bolt or something under engine that serves this purpose of bleeding air out of the cooling system? And that there might be more? Do you know if our KLX’s have these?

Think about it, how is a bolt under the engine going to bleed air out of the cooling system?

well i didn’t mean literally, I just don’t know where the locations of these bolts might be but I’ve heard of them. I didn’t get a chance to try your suggestion last evening because I had another plumbing problem.. my house. Talk about water troubles. I’ll give it a go today hopefully and report back

You're right that some systems have air bleed screws usually up high by the top of the radiator. The KLX doesn't. The radiator cap is high and the best place to bleed air. Remove the cap, and tap or squeeze the houses to burp any air. Start at the pump on the forward hoses and work up through the radiator and do it a few times. If needed, this can usually be done on a running engine, but you will probably have some overflow splash out that needs to be caught and then re topped off.

OK, actually on my KLX there is a bleed bolt, ON top of the LEFT RADIATOR! But, that's not going to bleed the whole system, it's complicated.
I would suggest reviewing the procedure with the manual and trying that first. I can't remember how I got the air out of the LRadaitor, but I don't remember using that bolt. Usually reading the manual is a good place to start.

One other thing is make sure when you put the thermostat back in, the air bleed hole is in the upper position (12 o'clock vs 6 o'clock).