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Hi all was quite hot in uk yesterday and found bobber leaking fuel out of filter at rear of bike called triumph they said normal and told me not to fill bike to top of tank dose not sound right to me bike was in direct sunlight for a while ,probably won’t be an issue as knowing uk weather that is probably summer over thanks Phil
 

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It does sound normal and probably due to slight overfill mixed with heat from the sun (expansion, & all that....)
I´d keep an eye on it, but it does sound common/normal if only leaking droplets.
Obviously if you find a pool of fuel - then i would go to the dealer.
 

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If you have just filled the bike to the brim and then left it in the sun, the heat will cause fuel to evaporate, building up pressure and thus pushing fuel out the expansion hose. Happens on both my Triumph and Kwak. I only fill to the brim if I know I will be riding the bike a far distance after filling. Don't sweat it.
 

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Agreed, if the fuel comes out of an underground tank its likely to be a lot cooler than ambient. If you fill to the brim it will expand a fair bit in the sun. That pressure has to be relieved somehow.
 

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I haven't had a look on the Triumph but the Kwak has a vent has that drains under the bike even with a vented cap. I would assume the Trumpy would be the same. Someone with a manual or who has the tank off the bike should be able to confirm this. Realistically though if the tank only leaks when you fill it right up I think it's obviously an over flow.
 

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OBM - that link doesn’t seem to work. Takes me straight to the “popular discussions” page...
Hmmm that’s odd eisen as when I click on it it takes me to the thread I wanted to post ??.
If it doesn’t work for others aswell I’m not sure apart from saying it’s a thread started by SXTony called (Filling the tank) around the end of Jan 2018 should hopefully be found by the search bar ??
 

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The caps are vented. Leakage should be around bung. Don't understand leakage under bike.
If you feel under the left hand side of the tank there is a rubber breather hose which I believe runs down to the rear of the bike. I assume this is also an overflow. If the overflow ran down on top of the potentially hot engine it would be a pretty poor design.
 

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If you feel under the left hand side of the tank there is a rubber breather hose which I believe runs down to the rear of the bike. I assume this is also an overflow. If the overflow ran down on top of the potentially hot engine it would be a pretty poor design.
Yes that is the overflow pipe, if you brim the tank that is where it will go, it is normal, do not brim the tank unless you are going to cover some miles straight away.
 
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