Do I Drill The Tank?



Hi. I'm adding a teardrop Happy Time fuel tank to "Mr. Hyde" my dual-engined bike as an auxiliary tank to feed the 43cc Mitsubishi engines' fuel tanks. I will install a T-fitting under the tank near the tank's shutoff valve, then steel lines towards frame stem(front) and seatpost(rear). Foot-long fuel hoses will feed into the top of the tanks, so I can fill both tanks by gassing up the teardrop tank.

Having a hard time finding fuel line grommets so the new rubber lines can enter the tank.

Should I just force the new line into the existing fuel grommet that feeds the carb lines?

Or drill through the gas caps? But then the hoses are further away/exposed from the engine than I'd like them to be.

Or should I just drill through the tops of the tanks so that the fuel lines will squeeze tightly thru the new hole I just drill?

The only grommet I can find is barely larger than the fuel hose, more like a thick o-ring with a groove in it. Should I use this one?

Thanks for help.


Active Member
Local time
3:35 AM
Jun 15, 2008
up top mountain -- Sourthern Ca.
we hope that you can find the proper parts needed

Or should I just drill through the tops of the tanks so that the fuel lines will squeeze tightly thru the new hole I just drill?

that doesn't sound like a good idea
say maybe with time and wear
a leak onto your engine ?
I know - I wouldn't worry about that much either
but - here on site we should promote -- SAFTY

hopefully you can find the parts you truly need

ride that thing


Mountainman, that's why I'm searching for the correct part and the right way of plumbing into the tanks. Besides, the tanks are under the engines. I know that I'd find the leak before it becomes problematic.

Man, this auxiliary tank is a GREAT idea. Now I don't have to prop the bike up the tree fork to get 18 oz of fuel into its 23 oz tanks. If all the tanks' air leaks up to the aux tank, the engines' tanks should fill to capacity, plus share the teardrop tank's 50 oz. cApacity. I can pull into any gas station, shut the petcock, add oil then gas to just ONE easily-accessible tank, open petcock and motor away.

My driving range will have increased from 20 miles to infinity. :eek:

No more propping the bike into the tree fork every 20 miles to fill the tanks.

No more mixed fuel to store at home.
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Anyway, I drilled the plastic tanks, screwed on brass barb fittings with liquid teflon and attached the 1/4" ID hoses. I also removed the Happy Time tank's filter screen, replacing it with a Fram inline car filter.

Time will tell if the fuel system stays intact.