luckydim Posted October 30, 2017 Report Share Posted October 30, 2017 After several micro-wheelies the fuel is spitting out of this small rubber tube (tank breather or vent) and everything around the cap becomes covered by the fuel. Maybe I have to connect this tube somewhere or fix the valve inside the cap? I hope that trial bike has to withstand much higher wheelies than my 10-cm tries. The bike is Evo 4T'12. Quote Link to comment Share on other sites More sharing options...
trapezeartist Posted October 30, 2017 Report Share Posted October 30, 2017 I just poke the breather tube down the hole in the middle of the steering head. I can't speak for your micro-wheelies, but my nano-wheelies don't cause a problem. 1 Quote Link to comment Share on other sites More sharing options...
portman Posted October 31, 2017 Report Share Posted October 31, 2017 The cap contains a one-way valve which should allow air in as the fuel tank empties but prevent fuel from escaping. I suggest you undo the cap and allow it to breathe for a while to evaporate any fuel trapped inside then blow and suck on the tube to see if it is working properly. Quote Link to comment Share on other sites More sharing options...
bilks Posted October 31, 2017 Report Share Posted October 31, 2017 Or could fit 1 of these https://www.ebay.co.uk/itm/MOTOCROSS-QUAD-BIKE-FUEL-CAP-PETROL-TANK-one-way-BREATHER-PIPE-HOSE-CRF-KTM/152293434767?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D46150%26meid%3Db2afd59935274b40982f028eb4255dfe%26pid%3D100005%26rk%3D1%26rkt%3D6%26mehot%3Dpp%26sd%3D352134780433&_trksid=p2047675.c100005.m1851 Trials znd MotorCross nearly double price lol Quote Link to comment Share on other sites More sharing options...
luckydim Posted November 1, 2017 Author Report Share Posted November 1, 2017 Putting the tube in the middle of steering head doesn't help since fuel still goes out - you just don't see it. I have cleaned the cap tube and valve using an air compressor (blew it from both sides) and it helped, fuel stopped bleeding for a while. But once I stopped the engine and did some hops the fuel started coming out of tube again. Maybe valve works in a different way when the engine is on because of vacuum inside the tank. Quote Link to comment Share on other sites More sharing options...
luckydim Posted November 2, 2017 Author Report Share Posted November 2, 2017 I have found a temporary solution - medicine dropper system. It can be easily connected to rubber breather through the metal needle. Now extra fuel comes to the system and then goes back to the tank in a few minutes. Quote Link to comment Share on other sites More sharing options...
klonheadd Posted November 2, 2017 Report Share Posted November 2, 2017 (edited) Be careful so there should be free access for air(or fuel) to get in the tank through the breather to let fuel out into carb. If not you it will lead to fuel starvation on higher rpm and lean condition with risk of overheating. My bike had recently experienced that issue. Because I had used old piece of tubing for the breather. After some time it got kinked and was blocked. Bike would seem to be running ok and after a while, maybe 30 mins started spitting coolant and cut off. Engine was unusually hot. I could start it but with more throttle it would die or would barely run on low rpm and overheat. Now everything is back to normal I need to get that one-way valve though. Edited November 3, 2017 by klonheadd Quote Link to comment Share on other sites More sharing options...
feetupfun Posted November 3, 2017 Report Share Posted November 3, 2017 Not a good idea to ride with something attached to the throttle cable 1 Quote Link to comment Share on other sites More sharing options...
luckydim Posted November 5, 2017 Author Report Share Posted November 5, 2017 I know it is not the best solution, but this is all I can have to keep riding until the fuel cap arrives to me from the UK. Btw tank still has free access to air and throttle cable is not affected by this attachment. I have ordered new cap that comes with the valve inside so I will post an update on this issue right after the test. Quote Link to comment Share on other sites More sharing options...
luckydim Posted November 26, 2017 Author Report Share Posted November 26, 2017 The problem was solved by changing the standard fuel cap to CSP Beta Evo cap . It doesn't have the breather pipe so it is much more convenient to use. Quote Link to comment Share on other sites More sharing options...
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