Glayne Posted June 28, 2021 Report Share Posted June 28, 2021 I feel like I should have wrapped my head around this, but I'm struggling. I pulled the 2012 gasser 280 out this morning , before ride I noticed milk coloured oil. Impeller, seal and shaft have been done within the last 40hrs. I changed the oil, still milky and rode for maybe 15mins, noticed the fan not coming on. After the ride I jumped the fan to a spare battery, it works great, testing the thermostat, it seems to always have resistance and isn't opening, put it in boiling water, no click and no real changes in resistance. So... I would say bad thermostat, but could this overheat coolant into the oil? or do I have multiple issues? Or am I missing something! FYI it is over 40 degrees celsius in western Canada! Yikes! Quote Link to comment Share on other sites More sharing options...
richt Posted June 28, 2021 Report Share Posted June 28, 2021 (edited) Any excessive pressure in the coolant should blow out of the rad breather hose under the tank. Check that the hose is clear and not kinked. The only other place it can go is via the pump seal. Excess pressure in the coolant can be caused by a leaking cylinder head O-ring, can possibly be a result of overheated engine. Test! Fill the radiator to the brim, Run the engine without the rad cap and look for bubbles coming up. If there is then you know the higher pressure of the cylinder is getting into the coolant and need to replace the O-ring seals. The high pressure is more than the Rad cap or the Pump seal can hold. 40 degrees 🥵 in that heat I would expect the fan to be running most of the time. the fan on mine comes on just after when the radiator gets is hot to hold your thumb on the top. Edited June 28, 2021 by richt 2 Quote Link to comment Share on other sites More sharing options...
Glayne Posted June 28, 2021 Author Report Share Posted June 28, 2021 (edited) Thanks richt, good idea to check for bubbles will take a look this afternoon. Am I correct that the thermostat should read Open Line, no resistance at room temperature? I think you may have half the problem here >>>>Excess pressure in the coolant can be caused by a leaking cylinder head O-ring, can possibly be a result of overheated engine.<<<< Edited June 28, 2021 by Glayne Quote Link to comment Share on other sites More sharing options...
richt Posted June 28, 2021 Report Share Posted June 28, 2021 (edited) "Am I correct that the thermostat should read Open Line, no resistance at room temperature?" On my wiring diagram power from the generator to the fan is halted by the Thermostat which is open line or circuit not made. Open line is high resistance so no current can pass, When the thermostat gets to hot temp it should switch to closed line, circuit made and low resistance to allow current to the fan. Does this make sense? Edited June 28, 2021 by richt 1 Quote Link to comment Share on other sites More sharing options...
Glayne Posted June 28, 2021 Author Report Share Posted June 28, 2021 Thanks richt, makes perfect sense, I have ordered a new thermostat, new O-rings and a new base gasket (I see some leakage there) Dave from Moto Trials West seems to always have what I need on the shelf! 1 Quote Link to comment Share on other sites More sharing options...
richt Posted June 28, 2021 Report Share Posted June 28, 2021 Excellent, Hope you get it sorted soon. Quote Link to comment Share on other sites More sharing options...
Glayne Posted June 29, 2021 Author Report Share Posted June 29, 2021 Checked for bubbles this afternoon, no such activity, seemed motor got hot, coolant was cool, only ran it for as long as the carb and hose had fuel as the fuel tank was off. Played in the water pump a bit, all looks shiny and new, no play on the shaft, would have thought the coolant would be warmer, probably a low rpm thing. Pulled exhaust off drained oil and coolant, will pull head and top end tomorrow, and will have parts for Wednesday. While it's 40+ a bit of tinkering is more desirable than an after work ride. 2013 gasser enduro has needed no engine tinkering after initial carb setup. Low hours though not sure how many, wish I put an hour meter on it. Next one I will. Quote Link to comment Share on other sites More sharing options...
richt Posted June 29, 2021 Report Share Posted June 29, 2021 How many times have you changed the oil since the first contamination to flush the bad stuff out? I'm hoping you only had it happen once and it 's just some residual coolant still trapped in there. After a miss-hap my bike was fully submerged in a 3 foot deep stream everything was full of water (Tank, Carb, Exhaust and Engine) It took about 4 oil changes to to flush it out. It looked like somebody had dumped a shopping trolley. Quote Link to comment Share on other sites More sharing options...
Glayne Posted June 29, 2021 Author Report Share Posted June 29, 2021 Ha! I know the feeling, put my YZ250 into a river, under water 20 years ago, must have been 1000 kicks to get it fired up and back to the truck on unfamilliar terrain in an unfamiliar country! Have only changed the oil once so far, let it drain over night. Will pick up some cheaper ATF for the next few changes. Quote Link to comment Share on other sites More sharing options...
Glayne Posted June 30, 2021 Author Report Share Posted June 30, 2021 Cylinder great, piston hmmmm. My enduro pistons are a little cleaner. How does this look for a trials piston without a power valve? Why no power valve? Quote Link to comment Share on other sites More sharing options...
richt Posted June 30, 2021 Report Share Posted June 30, 2021 The piston and bore look ok. The inner O-ring looks very poor and I reckon it has leaked hot gas into the coolant. Its not so clear on the photo but the top surface of the cylinder looks burnt/pitted, I hope it will clean up well. It may be worth turning it upside down onto an sheet of Wet & Dry sandpaper on a flat surface and polish it. at worst it may need skimming. What is the condition of the cylinder head looking like? Quote Link to comment Share on other sites More sharing options...
Glayne Posted June 30, 2021 Author Report Share Posted June 30, 2021 Both o-rings are starting to deteriorate, pretty sure I cooked them! coolant looked clean though. New S3 o-rings, base gasket and thermostat showed up today. Piston just looks dirty not pitted, pretty sure it was burning an unhealthy diet of coolant, will be cleaning it up for sure. Piston had new rings maybe 40hrs ago Head is dirty as well and will get a cleaning, however the plug looks good. Thanks richt for the suggestions. Quote Link to comment Share on other sites More sharing options...
Glayne Posted July 1, 2021 Author Report Share Posted July 1, 2021 More pictures here, head before and after, everything cleaned up easy. 43 degrees here for the first time ever, forest fire close, ash snowing from the sky. Picture of my truck hood is me parked at home for only 2 hours. Quote Link to comment Share on other sites More sharing options...
Glayne Posted July 1, 2021 Author Report Share Posted July 1, 2021 Nearly back together, kids needed damage control! Off work tomorrow for Canada day! Quote Link to comment Share on other sites More sharing options...
richt Posted July 1, 2021 Report Share Posted July 1, 2021 Cleaned up well, it should run like a new bike. 43 degrees that's too hot to ride, Its 18 degrees today in UK. I've never felt that type of heat except when I worked in a power station it still wasn't as hot as 43 though but at least you could go outside to cool down. How far away is the forest fire from you? On a lighter note, Your work bench gives the impression you've been busy (just like mine) but I hope you have used correct the tools and not the hammer and grips to fix your Gasser🤣 Enjoy Canada day and be careful. Quote Link to comment Share on other sites More sharing options...
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