I've got a 87 ex500 thats running hot! I've drained, flushed and refilled radiator. The thermostat seems ok, although it runs a little cooler with it removed. I'm not sure if the fan comes on, on it's own, I do know that when its hot if I turn off ignition and turn on again the fan will start. Any help is appreciated!

ThanX,
MX

 

When the engine gets hot, does it puke coolant out the radiator overflow tank? If it's an '87, I'm guessing it's a head gasket. The thermostat won't help this problem, and you're better off to leave it in place. Check your oil for any coolant contamination (you should see globules in the sight window.) However, if you don't see contaminant, it doesn'tnecessarilymean your head gasket is OK: I've had bad head gaskets without coolant getting into the oil.

 

Yes it pukes coolant out the overflow, just changed oil and it's fine. Any way of checking head gasket?

 

You can do a compression check, but without the proper tools, it can be a pita. I'd seriously bet on the head gasket. (What is technically happening, is that there is leakage between the cylinder(s) and the coolant ports in the head, causing pressure buildup. The coolant gets hot, expands, and the air gets into the coolant path and eventually out the overflow tube, because it has nowhere else to go.) The overflow tube (from the overflow tank to the ground)looks like a latte frother when it blows the hot coolant onto the pavement, (right?) Not to mention the coolant temperature gauge just keeps climbing......
It's not a bad job to replace the gasket, just make sure you label everything and get all of the old gasket and gunk off the head surface. Use Scotchbrite pads and Acetone. (Wear gloves.)

 

I'll do a comp. check, and let you know what I get, ThanX

 

hold on what coller are the electrodes of the spark plugs it could just be running lean start easy then move to advanst

 

Cant find my comp. tester, i'll buy anoth]er one tomorrow but I'm leaning towards the head gasket. Plugs are tan, but their old and 1 heat range higher than stock, so I'm gonna replace them with stock heat range. So where besides ebay can I get a head gasket for a decent price?

 

Check this http://www.carolinacycle.com/fiche_section_detail.asp

 

where they wetdid they have droplets of water on them is the bike modded at allintake or exhaust?

 

start the bike with the radiator cap off. If it starts shooting water/ coolant out of the radiator, it's a blown head gasket. If it doesn't. it could be a stuck thermostat or a bad water pump. It could be as simple as air trapped somewhere. Is there a bleed screw somewhere near the top of the engine. Check behind the cylinders or head. A bad radiator cap that is not sealing can cause overheating. Make sure the seat for the cap & center plunger is clean & sealing.