i have a lt500r 1987 that is as close to original as they come. my problems is i notice the over flow bottle is bubbleing and radator fluid come out the over flow. when idling and moving. second the bike runs fine until at top end it act like it starving for gas
any incite on carb jetting and cooling issues
i use engine ice
and i use 93 oct gas thanks

 

Is The fan comming on?

 

their is no fan on a lt500r it air cooled radiator



it blowing coolin out the over flow line???
i was told the caps go bad but i don't think that the problem

 

Any ligiud cooled ATV without a fan working proprerly will over heat in a instant,let alone not have one period.

Thats a bad design, on oil coolers a fan just asist,but on a rad the fan is a MUST. I seen them over heat just because the fan is wearing out and does not turn fast enough.

Fan stops, the coolant boils out of the over flow bottle,thats how it goes.

 

First thing i would do is make sure your water pump is working. These things have been around a long time. Ive seen the shaft broken on a few of these in the past.
A head gasget leak will also cause it to over heat. But first check the pump.
Good luck

 

With The ATV running look down the rad hole and see if the fluid flows to eliminate the pump.

Never knew they could even make a liquid cool system even work without a fan, it should be on all ATVs it would eliminate the need for a temp sensor and simplify things greatly.

 

try a new radiator cap. if its not sealing properly it will make it overheat and also allow it to fill overflow bottle. plus make sure your overflow bottle is about half full. and as far as the carb you need to find your float height specs and adjust it accordingly

 

i'm going to check the radiator to see if it coolant is circulating and then try a new cap. as far as carbs that next thanks

 

A new cap wouldn't hurt. I would check that your radiator isn't plugged. You should be able to see light through all the fins. Over time mud and crud fills those gaps and you lose cooling efficiency big time. The '87 was notorious for poor head bolts/head issues also. She will run hot if it is lean from a head/exhaust/etc leak. You should also pull the main jet, if it is clean try replacing it with a larger size(should be approx 17mm nut on bottom of carb. the main will be the small brass hex under that nut.)

 

Thats a good idea,get you rad cap pressure tested at a rad shop. My manual mention it first thing,it must hold 13 psi. The rad cap controls the pressure in the cooling system. Rad caps do wear out after awhile.