Moderators: trixynut, Mincehead, dicky, phuk72, Jak, Kevtrx849
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Flagman
- TRX-Enthusiast
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- Joined: Thu Jan 11, 2007 10:16 pm
- Location: Nantwich
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by Flagman » Mon Sep 14, 2009 8:11 pm
Ok, didn't use the bike for a few weeks, went to start it up strong smell of petrol, turned if over and petrol came out of the exhaust pipes!
Drained nearly 3 gallons of oil/ petrol mix from the engine.
My questions are has anyone else had this happen?
How can it happen? vacuum operated petrol tap is OK, vacuum operated pump is OK, stripped carb's floats and valves look OK bike only has 20k so shouldn't be worn, it runs very well
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phuk72
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by phuk72 » Mon Sep 14, 2009 8:17 pm
sounds like the carbs have overflowed and filled the barrels with petrol - then filling crank case
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Millsy
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by Millsy » Mon Sep 14, 2009 8:24 pm
Fuel tap duff....leaking through to "Prime".
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Flagman
- TRX-Enthusiast
- Posts: 12
- Joined: Thu Jan 11, 2007 10:16 pm
- Location: Nantwich
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by Flagman » Mon Sep 14, 2009 9:04 pm
OK, how can petrol overflow from the carbs? this should not be possible it has a vacuum fuel pump and a vacuum operated tap and no it wasn't on primp and is not leaking.
My thoughts on it, there was a leaking float valve and with a full tank which on a hot day with the bike in the sun outside and blocked tank breather? enough pressure to overcome the diaphragm in the tap and the pump to (slowly) siphon the fuel from the tank, pity the tap doesn't have an off position.
Was the tank breather badly routed and blocked? that would help build up some pressure, didn't check before I took the tank off.
Anyway it's running ok now and it did need an oil change and now its had a flush as well!
Thanks for the replies.
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Millsy
- TRX-Enthusiast
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by Millsy » Mon Sep 14, 2009 10:48 pm
If it was pressure related,only enough fuel to relieve that pressure would have flowed.
I suspect a dodgy fuel tap,coupled with a sticky float valve.
Anyway sounds like it's fixed itself......something we could all do with,a self healing bike.
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phuk72
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by phuk72 » Tue Sep 15, 2009 8:33 am
Think logically.
For the amount of fuel you describe, the only place it can have come from is the fuel tank (the carbs only hold a small amount). That means the fuel tap must be leaking - probbaly the seal.
As you suggest, it could have expanded in the heat but whatever the consequence, you need to identify the cause. FWIW, a second hand fuel cock is a damn site easier (and probably cheaper given Yamaha prices) than messing about with seals / orings etc.
