kristianybr Posted July 21, 2013 Share Posted July 21, 2013 Hi guys! I'm quite new too screwing and fixing anything in the engine of my bike (this is my first time,so please forgive my stupidity), and I have not yet gotten a complete understanding of how exactly anything works inside of it. Recently I was out driving in Oslo and my engine died, the bike is a Yamaha YBR 125 '05. I had almost ran out of oul (about 1/4 left) and it may have been a bit warmer then usual. (check out the link for more details) - (thanks to those who helped me out here) I got an idea of what might have gone wrong in this thread, but I think I need a bit more help. I have taken the whole engine and gear unit out of the frame of the bike, but frankly, I'm a bit afraid to break anything more if I continue to screw too much. Is there anything in particular I need to look after when taking the cylinder and the rest of the enigne apart? Is there any part I you would recommend me to start with? Hope someone will help me Link to comment Share on other sites More sharing options...
cosgrove Posted July 24, 2013 Share Posted July 24, 2013 Hi, as others have said,the most likely cause of your starting problem is going to be loss of compression. If you are lucky,when the engine got too hot it caused the piston rings to stick,although I can't explain the loss of oil in the first place. My advice would be to invest in a Haynes manual,and remove the head and barrel to check the rings and cylinder bore for scoring. If you want to remove the head etc,the following will help Remove the crankshaft end cap and timing cap,(left side of engine,2 caps with slots in) Remove camchain sprocket cover,(left side at top 2 bolts) Remove spark plug Remove valve cover caps Turn engine anti clockwise using socket on alternator bolt,(visible through crankshaft end cap hole) while looking for timing mark visible through timing cap hole and the camshaft sprocket mark lining up with mark on head,if you have got it right,both valves will be closed and the rockers will have some play in them, This is top dead centre,let me know if you get this far,and I will tell you what to do next. Pete Link to comment Share on other sites More sharing options...
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