nicksorg Posted April 19, 2016 Share Posted April 19, 2016 Well, that time of year I guess. Now that I have my bike running right after front head gasket replacement and valve adjustment, I let her idle for awhile in the garage. I came back 10 minutes later to find steam and antifreeze coming out the overflow tube at the bottom. Figuring it was a thermostat, I pulled the thermostat off, and ordered a new thermostat and radiator cap. With the nice weather today, I took the bike to work and after getting stuck in some traffic, the temp got really hot again and I had to pull over and let her cool awhile. When I did, I noticed some antifreeze loss again, but also felt the contents of the pipe from the radiator to the thermostat housing was boiling. Any other thoughts besides radiator cap? Thanks Nick Link to comment Share on other sites More sharing options...
Member Contributer BusyLittleShop Posted April 19, 2016 Member Contributer Share Posted April 19, 2016 Nick...Continuous engine temps above 220ºF or 104ºC is a problem and the logicalorder of items to trouble shoot are:1)Faulty radiator cap... system should hold 1.1 pressure ratio...2)Insufficient coolant...3)Passages blocked in the radiator, hose or water jacket...4)Air in the system...5)Thermostat stuck closed...6)Faulty temp meter or thermo sensor...7)Faulty fan...8)Faulty fan switch...Engine temps below 180ºF or 82ºC is an problem... it means that themoisture produced during combustion is not getting hot enough toevaporate out the pipe as steam... instead that moisture will migrateto the oil and produce a milky white contamination...Note normal by products of combustion is water... . Every gallon of gascreates roughly 8 pounds of water vapor... we all have witnessed waterescaping out of tail pipes on cold mornings...The sequence of events to trouble shoot are:1)Faulty temp meter...2)Thermostat stuck open...3)Faulty fan switch... (stuck on) Link to comment Share on other sites More sharing options...
nicksorg Posted April 19, 2016 Author Share Posted April 19, 2016 Thanks. Come to think of it, the radiator fans did not come on so this morning I tested the wires. I put a jumper wire on the two female sockets of the fan switch and the fans cycled on so the wiring is good. I'll order a new switch. Link to comment Share on other sites More sharing options...
Member Contributer Burns Posted April 19, 2016 Member Contributer Share Posted April 19, 2016 I used to get all sorts of corrosion/crap in the t-stat plug on the bottom rad, where the thermal switch for the fans is.. usually people just end up by-passing that and adding a hard switch in there so they can control the fans as needed. Link to comment Share on other sites More sharing options...
nicksorg Posted April 25, 2016 Author Share Posted April 25, 2016 New thermostat, radiator cap, and a bleed improved things but she was still running hot on the stand. I picked up a new thermal switch at NAPA Part # FS 130 made by Eichlin and it was a direct fit. An internet poster said that it had a lower temperature trigger. I tested today and the fans came on when the temp was about 1/3 - 1/2 way on the gauge. I'm very pleased. Link to comment Share on other sites More sharing options...
THRASHED Posted June 14, 2016 Share Posted June 14, 2016 Was having the same issues. Fan switch turned out to be the issue. New thermostat and Rad cap while it was sitting and flushed the radiator. Next up is a manual switch to keep it below temps while splitting lanes (which is, by the way, totally legal here in So Cal...LOL). Link to comment Share on other sites More sharing options...
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