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Post by mushroomdaddy on Feb 29, 2016 5:53:59 GMT -5
On my Sym 125 Shark 4V there's some fluid leaking from one on the engine drain rubber pipes. I'm not sure whether this is fuel or oil, it seems a bit of a mixture. I'd be grateful if anybody recognise the line indicated on the attached figure and might suggest what to look for to solve the problem. The Shark doesn't start well but seems run OK but after a while fluid blows out of the attached rubber hose-line  |
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Post by cookees on Mar 1, 2016 10:31:59 GMT -5
I believe that's simply a vent tube.
BTW..if your ever going to become a dealer you'll have to memorize these two sayings:
1. "They all do that"
2. "They come that way from the factory".
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Post by mushroomdaddy on Mar 1, 2016 16:31:17 GMT -5
Thanks for the reply and yes you're spot on, it is indeed a vent tube. The trouble is that it's venting (blowing) a lot of fluid, too much to ignore. So I'm trying to determine what that fluid is likely to be, oil or fuel. I'll have a closer look at the weekend but I was hoping somebody might recognise that part of the GY6 engine to give me a 'heads up' to likely cause.
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Post by mftic on Mar 1, 2016 18:29:46 GMT -5
Valve cover vent hose (which cookees said).
Too much oil?
They all do that? j/k
IDK. someone else will hopefully. Guess how much is too much?
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Leaking fluid
by: JoeyBee - Mar 2, 2016 18:17:47 GMT -5
via mobile
Post by JoeyBee on Mar 2, 2016 18:17:47 GMT -5
cookees is correct. It's a valve cover vent tune. It prevents a buildup of pressure in your engine. Without it, or if it get clogged, you can blow gaskets. How much is leaking out. It should only be an occasional drip. Have an oil change been done recently? The oil could have been overfilled. For a 150cc, 750ml is the "sweet spot".
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Post by pistonguy on Mar 3, 2016 7:51:25 GMT -5
I believe that's simply a vent tube. BTW..if your ever going to become a dealer you'll have to memorize these two sayings: 1. "They all do that" 2. "They come that way from the factory". 3. "Its the Nature of the Beast" 4. "It is what it is" |
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Post by ricardoguitars on Mar 3, 2016 8:20:36 GMT -5
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Post by JerryScript on Mar 3, 2016 14:39:24 GMT -5
Easiest to just put a fuel filter on the end of the vent tube, and zip tie it high on the frame.
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Post by ricardoguitars on Mar 3, 2016 15:55:33 GMT -5
Easiest to just put a fuel filter on the end of the vent tube, and zip tie it high on the frame. Sometimes solutions are so easy that you don't even think about them  |
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Post by pistonguy on Mar 3, 2016 15:57:47 GMT -5
Easiest to just put a fuel filter on the end of the vent tube, and zip tie it high on the frame.  Ive enjoyed this method for sometime. screw all that jackin around mounting a catch can |
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Post by mushroomdaddy on Mar 7, 2016 15:58:44 GMT -5
Well it's all my fault, as predicted – too much oil... way too much! Pulled some out over the weekend and now we're back to normal. I must have totally 'lost it' while doing my last oil change. I changed the oil a while back and then hadn't used the SYM during the winter months, that's why I failed to link the oil change with my problems. The vent tube no longer appears to be blowing oil, which I had never seen it do before. Hopefully I haven't done any lasting damage to seals etc. Many thanks to all for the help & advice  |
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Post by rockynv on Mar 7, 2016 22:18:13 GMT -5
Note that excessive purge can be caused by a number of things such as overfilling however do not overlook the need for regular valve adjustments. When the valve gaps get too large the valves will start closing way too soon during the compression stroke causing excess crankcase pressure which will vent out the purge tube filling it with oil.
Not waiting a few minutes for the engine to warm up and the rings to expand after a cold start will allow a lot of purge to build up if you are heavy on the throttle or ride at speeds over 25 mph before the engine reaches operating temperature on a 150. Simply starting the bike before you put your gloves on and riding easy the first few blocks can do much to reduce excess purge.
Some times when we add catch cans and such we are just masking whats really going on and not getting to the root of the problem and fixing it. To me a catch can is for a worn engine to pacify things until it can be rebuilt or for an engine that has had its compression boosted so high that the purge system can't handle it any longer however how many have boosted their GY6's compression to over 12:1?
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