Cibbersicks Posted October 9, 2011 Report Share Posted October 9, 2011 Question for those with fuel tanks with breather pipes protruding from the top of their fuel tanks like these: Do these tubes come straight from the main cavity of the tank? On mine, I have 2 tube ends at the bottom of the tank, one a breather, the other an overflow from the filler cap. Is it possible for me to blank these off permanently (cut the off and weld up the holes) and drill a hole in the top of the tank and re-weld a tube end on there? I already use one way valves coming from the 2 tubes at the bottom of the tank into a breather bottle attached to the air duct at the front of the bike, but it makes more sense for these to be at the top to me. Thoughts? Cheers T Link to comment Share on other sites More sharing options...
speedy sie Posted October 10, 2011 Report Share Posted October 10, 2011 on the tank i have it vents the tank itself. Link to comment Share on other sites More sharing options...
kaighn80 Posted October 10, 2011 Report Share Posted October 10, 2011 if it ain't broke etc... you'll prolly find that the pipes are braised in, this will not weld i don't care how good you are, i think that the tanks with breathers in the top have a splash guard, you don't want fuel spilling out and ending up on your wheels or engine, means you might have to open the tank up and put one in, getting the tank fuel tight again might be a mission, but with a little care and a lot of patience anything is possible. Link to comment Share on other sites More sharing options...
Superdunc Posted October 10, 2011 Report Share Posted October 10, 2011 I've used these on car tanks that I've made, and will be fitting one to my Ducati tank shortly. http://www.merlinmotorsport.co.uk/p3556/ROLL-OVER-VALVE-1/4-X-6JIC/product_info.html You will need to make up a small boss to weld to your tank, but yo won't need to do anything to the inside of the tank. Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 10, 2011 Author Report Share Posted October 10, 2011 Hmm, I've followed the kit HRC manual with regards to the one way valve into a bottle. Link to comment Share on other sites More sharing options...
nzknut Posted October 10, 2011 Report Share Posted October 10, 2011 lucky its all "optional" Have a look at an RGV VJ22 or a Honda RS125 tank, might be able to get one of those breathers and make it fit, the RGV being the easiest because its in a steel tank if you were to chop it out and weld it into your CBR's tank. Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 10, 2011 Author Report Share Posted October 10, 2011 Does it need the overflow? Do proper race tanks have these? Link to comment Share on other sites More sharing options...
Superdunc Posted October 10, 2011 Report Share Posted October 10, 2011 I can't see the pic as I'm on a work machine that blocks photfuckit. You need to be sure that your tank breather allows air to be drawn into the tank as the fuel level drops - if you've got the tank overflow and the breather routed into the same bottle you have to be very sure that the breather hose tip can't be covered by vented fuel collected in the bottle which can vacuum lock the breather and either cause the tank to start to collapse or starve the engine of fuel. As long as the catch tank is vented, it won't vacuum lock, any vented fuel will just be drawn back into the tank. You really shouldn't be getting very much, if any, fuel in the catch tank anyway, it's only there in case the one way valve fails*. * I've heard of engineered failures where the catch tank is used to increase the capacity of the fuel tank to circum navigate the regulations in formulas were capacity is restricted. Link to comment Share on other sites More sharing options...
nzknut Posted October 10, 2011 Report Share Posted October 10, 2011 As long as the catch tank is vented, it won't vacuum lock, any vented fuel will just be drawn back into the tank. You really shouldn't be getting very much, if any, fuel in the catch tank anyway, it's only there in case the one way valve fails*. * I've heard of engineered failures where the catch tank is used to increase the capacity of the fuel tank to circum navigate the regulations in formulas were capacity is restricted. NASCAR?? Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 10, 2011 Author Report Share Posted October 10, 2011 As long as the catch tank is vented, it won't vacuum lock, any vented fuel will just be drawn back into the tank. You really shouldn't be getting very much, if any, fuel in the catch tank anyway, it's only there in case the one way valve fails*. * I've heard of engineered failures where the catch tank is used to increase the capacity of the fuel tank to circum navigate the regulations in formulas were capacity is restricted. Catch tank vented - check Link to comment Share on other sites More sharing options...
uggiebear Posted October 10, 2011 Report Share Posted October 10, 2011 If your going ahead with this for aesthetic reason i recommend the mocal in tank breather valve the only other thing like it cost about a £100. http://www.rallynuts.com/motorsport-fuel-tank-vent-valves/mocal-in-tank-vent-breather-valve.html Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 10, 2011 Author Report Share Posted October 10, 2011 If your going ahead with this for aesthetic reason i recommend the mocal in tank breather valve the only other thing like it cost about a £100. http://www.rallynuts.com/motorsport-fuel-tank-vent-valves/mocal-in-tank-vent-breather-valve.html Not so much for aesthetics, my tank is a fuel cell under a cover. I'm just trying to minimise the junk inside the bike (under the tank) by potentially moving the breather pipe from the base of the tank to the top. This is an image of a ten Kate modified tank, as you can see there is a breather coming from the top, but I don't know what's going on underneath. Link to comment Share on other sites More sharing options...
Superdunc Posted October 10, 2011 Report Share Posted October 10, 2011 Not so much for aesthetics, my tank is a fuel cell under a cover. I'm just trying to minimise the junk inside the bike (under the tank) by potentially moving the breather pipe from the base of the tank to the top. This is an image of a ten Kate modified tank, as you can see there is a breather coming from the top, but I don't know what's going on underneath. Very little Tom, race bike breathers are just a one way valve, air gets in, nothing gets out. There are no chambers or baffles needed, though you could consider filling the tank with foam like Mark has done on his R1 in the mag. Road bikes have to have overly complicated breathers because of emissions regs. Then you get onto modern cars which as I'm sure you know, have to have carbon canisters, electronic purge valves, and god knows what else just let a bit of air into the tank, and absolutly nothing out. Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 10, 2011 Author Report Share Posted October 10, 2011 I am looking to go down the route of using tank foam as I can get some proper HRC packaged stuff at a decent cost. Would you reckon that the breather at the bottom of this ^ tank has just been blocked/welded over then Dunc? Being replaced by another one at the top? Link to comment Share on other sites More sharing options...
Superdunc Posted October 10, 2011 Report Share Posted October 10, 2011 I am looking to go down the route of using tank foam as I can get some proper HRC packaged stuff at a decent cost. Would you reckon that the breather at the bottom this ^ tank has just been blocked/welded over then Dunc? Being replaced by another one at the top? Yes. Be a bit cautious with tank foam, The stuff Mark has used, can be bought from Merlin Motorsport, who seem to be cheapest, and a few other places, I've used this on a few cars, with no issues. Older foam can break down when used with modern fuels blocking filters and pumps, so just beware that the HRC stuff isn't old stock. Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 10, 2011 Author Report Share Posted October 10, 2011 Just seen the stuff on Merlin, it's cheaper than my stuff so I'll go with that, nice one Dunc, secondly, the overflow (presumably from the fuel cap area) on race tanks - do they have them and/or are they needed? T Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 11, 2011 Author Report Share Posted October 11, 2011 Anyone? Link to comment Share on other sites More sharing options...
Timbo S2 Posted October 11, 2011 Report Share Posted October 11, 2011 Can see mine here. No catch tank provided... Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 11, 2011 Author Report Share Posted October 11, 2011 Thanks Tim but do you have anything else under the tank? As in an overflow for the cap? Link to comment Share on other sites More sharing options...
Mark/Foggy Posted October 11, 2011 Report Share Posted October 11, 2011 Hi matey, nothing underneath and nothing from the base of the filler, you could just drill some holes around the filler neck if you're not handy with a cloth. If you weld a boss into the top of the tank it might be worth getting it baffled a bit to stop fuel surge under braking which can be a problem. The question here is what do you want the valve to do?. Endurance tanks breath through the dry breaks and the valve stops expansion in the fuel from stopping the air flow through the valves when the tank is full. Waste goes to the bottle As for the Explo-safe, Yellow seems to be stable with Ethanol, does dye the fuel yellow though. The balck stuff seems to break up when you use high Ethanol, but you're not going to Le Mans are you. Link to comment Share on other sites More sharing options...
Superdunc Posted October 11, 2011 Report Share Posted October 11, 2011 Hi matey, nothing underneath and nothing from the base of the filler, you could just drill some holes around the filler neck if you're not handy with a cloth. If you weld a boss into the top of the tank it might be worth getting it baffled a bit to stop fuel surge under braking which can be a problem. The question here is what do you want the valve to do?. Endurance tanks breath through the dry breaks and the valve stops expansion in the fuel from stopping the air flow through the valves when the tank is full. Waste goes to the bottle As for the Explo-safe, Yellow seems to be stable with Ethanol, does dye the fuel yellow though. The balck stuff seems to break up when you use high Ethanol, but you're not going to Le Mans are you. Had issues with the yellow stuff, with pump and race fuel. Link to comment Share on other sites More sharing options...
Mark/Foggy Posted October 11, 2011 Report Share Posted October 11, 2011 Interesting! Usually works, but I'm guessing that there could be a lot of crap floating about. Got a preferred colour? Link to comment Share on other sites More sharing options...
Superdunc Posted October 11, 2011 Report Share Posted October 11, 2011 Interesting! Usually works, but I'm guessing that there could be a lot of crap floating about. Got a preferred colour? Blue, it matches my eyes. Seriously I think Premier and ATL usually supply the blue stuff unless you run methanol, ISTR about ten years ago we had a problem with the yellow stuff which had only done one season, we contacted the manufacturer and they muttered and mumbled and set us the blue stuff FOC, about £700 worth at the time. The stuff's exspensive so people don't throw out old stock so there is some of the older stuff about, I only see the black stuff in 20+ year old tanks. Interestingly the yellow stuff, used as a sponge, is really good for removing bug guts from the front of your car/bike. Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 11, 2011 Author Report Share Posted October 11, 2011 Hi matey, nothing underneath and nothing from the base of the filler, you could just drill some holes around the filler neck if you're not handy with a cloth. If you weld a boss into the top of the tank it might be worth getting it baffled a bit to stop fuel surge under braking which can be a problem. The question here is what do you want the valve to do?. Endurance tanks breath through the dry breaks and the valve stops expansion in the fuel from stopping the air flow through the valves when the tank is full. Waste goes to the bottle As for the Explo-safe, Yellow seems to be stable with Ethanol, does dye the fuel yellow though. The balck stuff seems to break up when you use high Ethanol, but you're not going to Le Mans are you. Great stuff thanks Mark, with regards to what I want the valve to do, basically, I want it to work pretty much as it does now, as in letting air in, but no fuel out, but like I said I want it at the top of the tank to free up space at the bottom of it, in an attempt to minimise the tubing etc. I may even use the correct amount of tank foam, unlike our italian friends, where a pop bottle will do.... Link to comment Share on other sites More sharing options...
Mark/Foggy Posted October 12, 2011 Report Share Posted October 12, 2011 Anything to get through scrutineering Link to comment Share on other sites More sharing options...
SAB Posted October 27, 2011 Report Share Posted October 27, 2011 Not that it hasn't been fleshed out already in this thread, but the Fabtech tanks vent directly from the tank on the 3 that I have. It's simply a metal tube that runs from near the fuel fill and exits on top near the front. Link to comment Share on other sites More sharing options...
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