Hey all. So I was lucky enough to find a 1980 Yamaha Special with around 8,000 miles on it on craigslist near my area. This is my FIRST motorcycle so I am new to all this but have been trying to read a lot. Ok so after buying the bike I realized it was running on only one cylinder (left exhaust was cold and not much power). Pulled the plugs and the left one was gas fouled so I wiped it off and put it back in, and both cylinders fired right up, and I found out previous owner had adjusted idle screw to run on one cylinder so I turned it back down to idle at 1200ish rpm. Rode the bike a lot and noticed a clear/oily leak from bottom of bike that smelled a bit gassy that would only leak right after riding. Also if I let the bike sit for over a day without riding the left plug would foul again. I decided to smell the oil in the crank case and it smelled quite gassy to me. So I'm getting gas in the oil and I don't know why.
First thing I did was change the oil and filter. Thought it might be the petcock so I pulled off the gas line from the vacuum petcock and kept it set it to ON (which should not leak) and left a cup under it all night and not a single drip. Pulled the carbs and they must have been gone through because they looked very clean to me (and the screws that hold the bowls on did not match.) It had a new gasket and needles but I changed the needles anyway and the float didn't look like it was sticking at all and both were even. I didn't get a chance to take the rest of the carbs apart to actually check the needle seat but I figured with brand new needles it should be ok. Started riding it again and I can smell progressively more gassy oil after each time I ride. I also looked at the fuel/air adjustment screws and they both were set at the same level so I assumed if they are even but set wrong both carbs/plugs would be having issues (not just left plug), unless maybe the kickstand side (left side) lean is why only that plug is fouling and both carbs are set too rich???What is my next move? Aren't there only a few ways gas could be getting into the crank case? The bike runs really smooth to me and doesn't really stutter at all. It pops on deceleration and sometimes when she's warmed up and I rev the engine the rpm's are a little slow to come back down but that's all I've noticed. LOVE the bike overall but I can't ride it with gas in the oil so I would really appreciate some guidance. Thanks here's a few pics.
First thing I did was change the oil and filter. Thought it might be the petcock so I pulled off the gas line from the vacuum petcock and kept it set it to ON (which should not leak) and left a cup under it all night and not a single drip. Pulled the carbs and they must have been gone through because they looked very clean to me (and the screws that hold the bowls on did not match.) It had a new gasket and needles but I changed the needles anyway and the float didn't look like it was sticking at all and both were even. I didn't get a chance to take the rest of the carbs apart to actually check the needle seat but I figured with brand new needles it should be ok. Started riding it again and I can smell progressively more gassy oil after each time I ride. I also looked at the fuel/air adjustment screws and they both were set at the same level so I assumed if they are even but set wrong both carbs/plugs would be having issues (not just left plug), unless maybe the kickstand side (left side) lean is why only that plug is fouling and both carbs are set too rich???What is my next move? Aren't there only a few ways gas could be getting into the crank case? The bike runs really smooth to me and doesn't really stutter at all. It pops on deceleration and sometimes when she's warmed up and I rev the engine the rpm's are a little slow to come back down but that's all I've noticed. LOVE the bike overall but I can't ride it with gas in the oil so I would really appreciate some guidance. Thanks here's a few pics.
