Low budget 1+ gallon gas tank from plastic gas containers (~$8-15)

[bakaneko]

Hello, first off I recognize there are folks here looking to build the best and nicest MBs and then there are folks looking for a low budget ride or fun. This is for both for the low budget folks I hope this helps expand their range and for the purest hobbyist maybe they can create a better looking setup. Who knows. Let me start with the the reasons, describe the build, and then list out the limitations.

Reasons
- I want long or extremely long range depending on the gas efficiency and throttle usage
- No need to constantly worry about the gas levels depending on the gas container size; also container is not 100% opaque so you can see gas levels without opening cap
- I want to pump gas directly from the gas station pump into the bike without fear of using the high pressure gas pumps in a small tank above a hot motor... ie fire fear
- Stock gas tank is too small for the gas pumps (you get a lot of splashing...)
- I am a 2-stroke guy and it sucks to have to get gas, mix oil, transfer some to the stock tank; this eliminates that (pressure from gas pump is good enough to mix the oil)

Build
- Materials: Walmart, Home Depot, Menards gas containers for $8+ (1+ gallon), solvent proof sealant ($1), super glue ($1) - I used the cheapest sealant but please use better gas specified proof sealant
1. Drill a hole slightly smaller than your gas intake valve into the bottom of the gas container (see pic)
2. Connect the plastic tube to the output valve; use more tubing if you are not certain (I didn't do this step and it is hard to secure the tube after)
3. Screw in the gas value along with the plastic washer flush to the gas container
4. Apply a gas and water resistant sealant on top of the gas valve and set dry for specified time
5. Apply a second layer and use hard setting super glue as much as possible on top of that
6. Test valve for several days for leaks (I tested for 1 week)
7. Securely affix the new tank to the rear rack of the bike (might have to elevate tank depending on your engine placement; I elevated it 4-5 inches with wood)
8. Implement an inward pressure valve at the top of the gas container (I did it at top of handle). The valve needs to only open inwards to relieve vacuum pressure. You can do this with a small hole and some plastic.

Limitations
- The connection to the valve is weak. In the stock tanks, it is in cased in metal. The way I place the valve on the rear rack limits the risk of anything hitting it. But, a more able person can build a casing around the valve
- Having this on your rear rack or anywhere is unsightly. I covered mine with a Toyota bag... I know it still looks like crap but I am sure more aesthetic coverings or casing can be made for cheap
- You will need a rear rack but I guess it is possible to mount in the middle of the bike or the front bar

So, I tested the valve for leaks for about a week and there was no leaks. I then ran the MB with the gas container tank for 20 miles yesterday. I wanted to run it more before posting but the temperature dropped here to 10F... I am using a 1 gallon tank but there are 2 and 5 gallon tanks and I carry oil in the right amount for the gas pump. I know there are some folks here that go on long endurance rides 100 miles+; I think this can really help. Here are some pictures.

 

[Wolfshoes]

1.5 liter tank = 50 oz., 1 gal tank = 128 oz, total of 178 oz at about 1 ounce per mile= about 175 miles. At 25 mph would make for a range of about 7 hrs. I have heard of a MB rider going from Darien, WI in southern Wisconsin to the Upper Peninsula of Michigan. On a trip like that plenty of gas could come in handy. You may have some interesting plans.

 

[troyg]

If you're not frame mounted, a 1gal antifreeze bottle worked with a heat gun will fit right between your legs, nice and low, even if there's a leak it only hits the ground, and maybe your BB.
I can do a 186 mile trip with the GEBE no fill-ups

 

[JunkyardDog]

I used to have a friction drive MB (unfortunately it was stolen) and I installed a Delta Compact pannier (nylon) onto the engine/drive bracket on the opposite side to the engine. I carried a 5 qt. oil jug full of premix in it. Many people will say you need an MSR bottle or something similar to carry gas in, but you don't. It is just as safe to carry gas in a plastic container as it is a metal one. And it doesn't need to be an "approved" gas container either. It just needs to be strong enough, like don't try to carry gas in a milk jug. Unfortunately the setup you have will eventually fail at the connection to the tank. I would just carry the gas container full of premix, and refill the bikes tank from it. Carry a funnel if necessary.

 

[bakaneko]

Yeah, I still like the setup and I think it can be done appropriately by someone that is mechanically more able. Unfortunately for me, this was not the source of my MB failure. I recently had the chain tensioner come lose, destroy a spoke, lock the backwheel, and somehow that seize my engine too (cant turn engine). I had 1500 miles on the engine. Sucks... Planning next build

 

[JunkyardDog]

The chain tensioner failure is all to familiar to me. I had one do the same thing. It got sucked into the rear wheel, locking the wheel and causing me to crash. Unfortunately I was in a bike lane just inches from fast moving traffic. Lucky I wasn't killed. I will NEVER again use one of those things. That is the reason I switched to friction drive. That setup was trouble free for 3 years, until it got stolen. I am not an engineer by any means, but I am a former auto and truck mechanic. I can design a tensioner 10 times better than what comes with these kits. But the thing is, if I can, so can almost anyone else. The bracket needs to be several times heavier than it is, and the "roller" needs to be steel, with teeth, and quality bearings. It also needs to be designed like a derailleur, so it can constantly move under spring pressure, as these chains are not consistant, they have tight spots and loose spots. Another solution is to not use a pulley at all, but a round block of rubber. My dual sport motorcycle has a rubber cushion on top of the swingarm pivot, where the chain rubs. The side plates cut groves into it, but that stops when it wears down to where the rollers contact it. It would also need to be attached to the bike in a way that it absolutely cannot move. It could be welded to the chainstay, or it could be attached to a cross piece of flat metal stock attached crossways between the chainstay and seatstay. There are so many possibilities it seems ridiculous that someone hasn't come up with something way better. I wouldn't expect it to come with the cheap Chinese kits, but a company like Sikk Bike Parts could certainly design and sell something safe and reliable. I am considering building a shifter bike with a 4 stroke engine (Honda GX35) using their parts. But there are still issues with the 4 stroke mount kits not fitting bikes properly. Something else an actual engineer needs to take a look at.

 

[bakaneko]

Yeh, crassius help me fix the issue with the bike. It turned out to be a bundled up chain in the drive train sprocket. I still have the crappy tensioner but I placed a metal bar across two bike frame bars and against the tensioner. Hopefully, that will prevent the tensioner from slipping into the spokes.

Just an update regarding the cheap gas container tank. Overall, it works. I love zipping around and not having to worry about gas and just really pushing the consistently high speeds. The one remaining issue is trying to create a proper gas valve for the vacuum generated during engine operation. Right now, I am just using a plug with a small hole in the bottom but it is not ideal. I am going to go ask the plumbing department guys next if they have a proper valve (allows air in and does not allow any out).

 

[jatgm1]

Yeh, crassius help me fix the issue with the bike. It turned out to be a bundled up chain in the drive train sprocket. I still have the crappy tensioner but I placed a metal bar across two bike frame bars and against the tensioner. Hopefully, that will prevent the tensioner from slipping into the spokes.

Just an update regarding the cheap gas container tank. Overall, it works. I love zipping around and not having to worry about gas and just really pushing the consistently high speeds. The one remaining issue is trying to create a proper gas valve for the vacuum generated during engine operation. Right now, I am just using a plug with a small hole in the bottom but it is not ideal. I am going to go ask the plumbing department guys next if they have a proper valve (allows air in and does not allow any out).

you mean a check valve?

 

[shiggley]

The chain tensioner failure is all to familiar to me. I had one do the same thing. It got sucked into the rear wheel, locking the wheel and causing me to crash. Unfortunately I was in a bike lane just inches from fast moving traffic. Lucky I wasn't killed. I will NEVER again use one of those things. That is the reason I switched to friction drive. That setup was trouble free for 3 years, until it got stolen. I am not an engineer by any means, but I am a former auto and truck mechanic. I can design a tensioner 10 times better than what comes with these kits. But the thing is, if I can, so can almost anyone else. The bracket needs to be several times heavier than it is, and the "roller" needs to be steel, with teeth, and quality bearings. It also needs to be designed like a derailleur, so it can constantly move under spring pressure, as these chains are not consistant, they have tight spots and loose spots. Another solution is to not use a pulley at all, but a round block of rubber. My dual sport motorcycle has a rubber cushion on top of the swingarm pivot, where the chain rubs. The side plates cut groves into it, but that stops when it wears down to where the rollers contact it. It would also need to be attached to the bike in a way that it absolutely cannot move. It could be welded to the chainstay, or it could be attached to a cross piece of flat metal stock attached crossways between the chainstay and seatstay. There are so many possibilities it seems ridiculous that someone hasn't come up with something way better. I wouldn't expect it to come with the cheap Chinese kits, but a company like Sikk Bike Parts could certainly design and sell something safe and reliable. I am considering building a shifter bike with a 4 stroke engine (Honda GX35) using their parts. But there are still issues with the 4 stroke mount kits not fitting bikes properly. Something else an actual engineer needs to take a look at.

I went with this one https://www.kingsmotorbikes.com/products/arch-idler-pulley-chain-tensioner?variant=12504165892 hopefully with the dual mounting points it will stay out of the spokes, but i'm still in the build phase so time will tell. i do like the sprocket style roller idea though!