I just finished rebuilding the engine on my 2013 850 touring after the timing gear spun. Over the July 4th weekend in put 11 hours and about 130 miles on it and as far as the engine goes it ran great, however it did overheat twice which it has not done before. It did not get to engine shutting down or anything, but the light came on and it went into limp mode at which point I immediately shut it down to cool.

The first time it overheated I looked at the radiator and it was full of seeds from going through fields, it was packed. After letting it cool for 30 minutes i drove it less than a mile to the house and let it sit for the night. The next morning i pulled the front plastics off and blew all of the seeds out from the back using a flashlight to check that the fins were clear, at this point I thought I had it licked. However it did the same thing the next day. Both times it took about an hour or more of riding at fairly low speeds to overheat and it was 90+ degrees outside both days. I checked the oil and no water in it so it is not a head gasket issues, and it did not loose any coolant. I did notice at one point last night that we stopped to wait for some pigs to come out and after shutting it down I could hear bubbling in the radiator. I later took the cap off and started the engine and could see fluid moving, I also felt the upper hose and it was hot so fluid is moving.

So would you think I need to lift the front end to burp it or would you guess thermostat? I can pull the thermostat to check it in boiling water tomorrow, but it never overheated before the rebuild. The fan is working and it comes on as needed. I have ordered a Koso digital thermometer to put on it, but I need to fix whatever the issues is. Of course when I rebuilt the engine it was totally dry and i made sure to run water through all of the passages before reassembly to make sure there was no unwanted trash is any of them. I used 50/50 premix green coolant and like I said it is not loosing any. I am inclined to think it needs to be burped but wanted to see if anyone else had any ideas.

On another note it was great to have her back up and running again, and she does run. I took it easy for about the first 45 minutes varying the throttle and speed (only had to replace exhaust valves so not a full rebuild so no long breakin) until we ran across a pig across a large field. At that point it was put up or shut up time and I put the whip to her and she RAN!! 🙂 I just need to get the overheating issue resolved and we will be good…