Swirl tanks are usually on off-road vehicles to provide stable pickup area for pump in event vehicle goes through lots of pitches and rolls. Typically converting to gravity feed reduces tank capacity by 1/2 as when tank gets low, there's not enough force pushing fuel down to properly fill carbs. Try connecting pump directly to main tank 1st and see how that goes. If works well, remove 2ndary tank
1994 Yamaha XV1100, thinking of deleting secondary / reserve gas tank
I've had a few bikes before this XV1100 but this is the first one that the fuel had to go to a secondary tank, then down to a fuel pump, then back up to the carbs. I don't understand why the complicated system. I have found lots of rust in the second tank and it needs to be replaced. I'm thinking of just removing that system and just going gravity tank to carb. That is if I can find a petcock suitable to the purpose.
There must be others that have done this, any tips?
Thanks in advance for any input you can offer.
There must be others that have done this, any tips?
Thanks in advance for any input you can offer.
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That's a great idea. I'm not too worried about the reduced volume of gas available. There will still be enough to get to the next gas stationSwirl tanks are usually on off-road vehicles to provide stable pickup area for pump in event vehicle goes through lots of pitches and rolls. Typically converting to gravity feed reduces tank capacity by 1/2 as when tank gets low, there's not enough force pushing fuel down to properly fill carbs. Try connecting pump directly to main tank 1st and see how that goes. If worms well, remove 2ndary tank
There are 2 things I would need to figure out though. There is an electric reserve switch and a low fuel warning light. I'll have to see what effect leaving the second tank out of the system will have. I'm guessing most of the expected reserve would be the second tank. I don't know if there is any gas remaining in the main tank when the low on fuel light comes on. Also, there are 2 gas lines coming from the main tank and going to the second tank. I'm hoping that one is the main line and the other is the reserve, I don't know. Might be able to just "T" them together. Thanks a lot for taking the time to reply. Gives me a great alternative to think about.
Generally bikes that have a fuel pump use a float valve seat that has a much smaller orifice in the seat than what is used with gravity feed models. There is a numbering system for float valve sizes. Can't remember how it goes right now. Maybe some one can look it up on the innerweb if interested.
The secondary tank:
Been so long since I've dealt with that model... Hard to remember particulars about the plumbing for the lower tank but the larger hose supplies fuel down to the tank and I'm thinking the smaller hose is a return fuel / vent / pressure relief type of thing (lets air out, high tech explanation .. Lol) so fuel can flow down to the lower tank.
S F
The secondary tank:
Been so long since I've dealt with that model... Hard to remember particulars about the plumbing for the lower tank but the larger hose supplies fuel down to the tank and I'm thinking the smaller hose is a return fuel / vent / pressure relief type of thing (lets air out, high tech explanation .. Lol) so fuel can flow down to the lower tank.
S F
Good info, thanks. I don't understand the need, but I don't have a problem keeping the fuel pump. I'm mostly looking to delete the secondary tank because it's rusty. Used replacements are $100+ and no guarantee they are clean inside. Both hoses run from main tank to secondary tank. I guess the small one could be some kind of vent, I'll have to see if I can confirm that. If so it could be deleted with the secondary tank. Thanks for the input.Generally bikes that have a fuel pump use a float valve seat that has a much smaller orifice in the seat than what is used with gravity feed models. There is a numbering system for float valve sizes. Can't remember how it goes right now. Maybe some one can look it up on the innerweb if interested.
The secondary tank:
Been so long since I've dealt with that model... Hard to remember particulars about the plumbing for the lower tank but the larger hose supplies fuel down to the tank and I'm thinking the smaller hose is a return fuel / vent / pressure relief type of thing (lets air out, high tech explanation .. Lol) so fuel can flow down to the lower tank.
S F
See, if there was only the fuel hose supplying fuel to the lower tank fuel could not reliably flow because as fuel goes in it must displace the air (or fuel) in the tank in order for that fuel flow to happen. You can not put something in an enclosed tank if you do not make room for it in the tank by allowing air, or whatever, to exit as the fuel comes in. That is what the small hose does and why it has that hose.Both hoses run from main tank to secondary tank. I guess the small one could be some kind of vent, I'll have to see if I can confirm that. If so it could be deleted with the secondary tank. Thanks for the input.
It is not a vent hose but I was having trouble explaining. Hope I did better this time.
I do not see why you could not just plug the spigot at tank for the small hose and put an in-line petcock in the large hose then run a hose from that straight to the fuel pump. You will need to reduce the size of the hose somehow so it will fit your petcock nipples because I don't know if you could ever find a petcock with the sizes you would need otherwise.
S F
Got it. I would be bad to just vent the secondary tank to the air, could go boom! I think I'm going to go ahead and try this. If something doesn't work out it would be easy enough to get a new secondary tank and put it back to original. Thanks for the help.See, if there was only the fuel hose supplying fuel to the lower tank fuel could not reliably flow because as fuel goes in it must displace the air (or fuel) in the tank in order for that fuel flow to happen. You can not put something in an enclosed tank if you do not make room for it in the tank by allowing air, or whatever, to exit as the fuel comes in. That is what the small hose does and why it has that hose.
It is not a vent hose but I was having trouble explaining. Hope I did better this time.
I do not see why you could not just plug the spigot at tank for the small hose and put an in-line petcock in the large hose then run a hose from that straight to the fuel pump. You will need to reduce the size of the hose somehow so it will fit your petcock nipples because I don't know if you could ever find a petcock with the sizes you would need otherwise.
S F
Maybe remove the second tank and give it a shot. Personally, I would remove it and clean the inside. It is not that difficult and you can apply a coating afterwards to prevent future rust. Being a small tank it shouldn't be an expensive operation.
Thanks for taking the time to reply. The secondary tank is quite rusty. When shaken, I can hear large chunks of rusty metal banging around in there. I'm afraid there are some very thin areas in the wall now. I was thinking of cleaning it at first and thought of coating it with one of the many products available for lining gas tanks. But there is a significant number of people who warn against coatings because they break down in time. I will likely try eliminating the second tank first. If any problems arise I will decide if I should repair or replace the tank. Thanks again for your input.Maybe remove the second tank and give it a shot. Personally, I would remove it and clean the inside. It is not that difficult and you can apply a coating afterwards to prevent future rust. Being a small tank it shouldn't be an expensive operation.
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