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Discussion Starter #1
My fuel tank has no vent hole between the fuel cap mount screw holes. After considering welding a quarter turn or threaded filler neck to the tank, which would be the cheaper option, I decided to just buy a cap assembly. Problem I have is that my tank doesn't have that vent hole between the mounting screw holes. Will the cap with the vent nipple still work for me? Or do I have the wrong fuel tank for this bike? Mounts perfectly but I haven't seen any vn750 tanks online that don't have the vent hole...


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Where did you get the tank? ALL Vn750 tanks have that "hole" which is actually a tube that exits at the back of the tank nearest you.
 

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Discussion Starter #3
Came with the bike when it was given to me. Not the original I believe. Engine still had the California stuff on it so I think it's just a non California tank. Which makes sense, I was just looking at a few pictures again and realized that it was probably connected to those tubes, which I don't have either. Which makes me think that the cap assembly will work just fine.

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VN700 / VN750 model years 1985 - 1987 did not vent through the gas tank. They vented directly though the gas cap. You must have a '85 - '87 gas tank. A '88 or newer gas cap will fit, but you will need to modify the vent (e.g., cut the vent nipple or drill a vent in the back of the cap).
 

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VN700 / VN750 model years 1985 - 1987 did not vent through the gas tank. They vented directly though the gas cap. You must have a '85 - '87 gas tank. A '88 or newer gas cap will fit, but you will need to modify the vent (e.g., cut the vent nipple or drill a vent in the back of the cap).
thats one I didnt know..

what are we up to now? 3 differences over a 21 year production run?
 

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Discussion Starter #6
VN700 / VN750 model years 1985 - 1987 did not vent through the gas tank. They vented directly though the gas cap. You must have a '85 - '87 gas tank. A '88 or newer gas cap will fit, but you will need to modify the vent (e.g., cut the vent nipple or drill a vent in the back of the cap).
Nice, thanks for the info. Shouldn't be too hard to drill a hole and put in a grommet that will fit the nipple then.

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thats one I didnt know..

what are we up to now? 3 differences over a 21 year production run?
Actually there is about a dozen small differences through the years. Petcock changed, master cylinder changed. Early bikes had aluminum parts like the backrest and seat rail, which oxidized in time, that were eventually chrome plated to avoid that. Speedo and tack upper "buckets" were eventually chromed too (2003).(they were painted, and prone to rust) Carb drain screws changed. As pointed out here, fuel caps changed.
Original model had black engine and black wheels. Seat changed from then too.
Not to mention paint graphics. There's a few more but these are the ones just off the top of my head... ;)
 

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Wow. Learn something everyday! I didn't know that either about the early model venting being different.

I stand corrected.
 

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The nipple/hole combo is designed to direct fuel away from the rider when there is an overflow due to overpressurization. The hole in later model tanks redirects that overflow through a tube in the tank, and out the back under the seat. The nipple/hole does NOT have a pressure/liquid-tight seal, since there is no pressure in the hole, so any liquid coming out of the nipple just runs unobstructed through the tube.

Adding a grommet back into the gas tank will not accommodate the engineered pressure regulator in the fuel cap, and will likely lead to leaking sloshing fuel out of the gas tank at the grommet. IMO it would be better to file down the nipple. That would make the cap only as safe as a directly vented cap (overpressurized fuel at the filler neck could still come out of the tank into your lap), but the seal of the gas tank would be uncompromised, so you would be less likely to have a leak than if you drilled a hole and installed a grommet for the the nipple to seat into.
 

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Mine is set up the same way, with no actual hole. It always leaks out of the filler neck.
 

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Discussion Starter #11
Well went ahead and bought the cap, ill give it a try. I'll skip drilling a hole. It won't be any worse than a normal vented cap if it has the valve in it. Thanks for all the info guys. At least I'll have a cap now, the one time I've ridden it I used duct tape.

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