Gas tank volume

[bheezy27403]

 So, how big is the tank on a '74. Quick search says 4.23 gal. I've also seen there were a couple sizes of tanks. A bulbous one and a thin one. Mine seems to be thin. I ask because I hit reserve on the way to work this morn (with 80 on the tripometer) and was wondering how many miles I had in reserve. I imagine it depends on the size of the tank.

[m in sc]

i typically get to reserve at about 2.5  gallons used.  us models are all the same sized tanks 73-75.

[bheezy27403]

I ran out of gas on the way home from work yesterday. Fortunately I costed straight up to a pump. I had to put 93 ethanol in it but it won't be in there long as much as I've been riding her. I put in 2.43 gal with 88 on the odo so that's about 35 mpg. Not bad. I am however concerned about the very short distance (8 miles) from reserve until empty. That will not be good if I'm up in the mountains. I suppose I could try to lean the bike over and get some more fuel over the spine to the left side of the tank? Where i ride in the mountains 8 miles means pushing.

[m in sc]

that sounds pretty normal actually. I've rarely come close to running out up in the mts myself, however, you can always go up one on the front sprocket and get more mileage.   

actually hit reserve on the r5 on the way in this morning, put about 2 gallons in, but not super full maybe 1-1.5 inches under the filler.

[bheezy27403]

Thanks Mark.  I'll just be sure to not get too deep in without some sort of back up plan.

[soonerbillz]

So being ultra conservative maybe a hundred miles per tank?

[Striker1423]

I subscribe to the "100 mile club" on the RD. That means look for gas around 100 miles or prepare to walk.

[m in sc]

wait.. your reserve should be more than 8 miles worth of fuel. is the crossover on the tank connected? and does it run under the frame rails?

[Striker1423]

I agree, you should get around 15-20 miles or so before reserve is gone.

[pidjones]

Mid-summer, I rode the RD400c in to the weekly gathering. Meant to stop on the way in (~20 miles) but forgot. Figured I could do it on the way home. Got ~100 yards up the hill and she started to sputter - coasted into a station and added a gallon and a half of premium 10%. Topped off with premium pure gas with Stabil as soon as I got home!

[bheezy27403]

wait.. your reserve should be more than 8 miles worth of fuel. is the crossover on the tank connected? and does it run under the frame rails?

That was my point. I figured I had a gallon or so left so I figured 20 more to be safe.  If I ran out and only put 2.43 in that means there was definitely more in there. I'll have to check tomorrow About the "crossover pipe" as I didn't know there was one. I'm assuming its a tube that goes from the right side of the tank to the carb? Got a pic?

[Striker1423]

The tube connects under the gas tank under the center frame tube above the carbs. This allows the gas to migrate and equalize from one side of the tank to the other.

[m in sc]

exactly. there are 2 nipples under tank, neither should go to a carb, but connect to each other. 

[bheezy27403]

Yes it's there. I'll take it off tonight and inspect it to make sure it's not clogged.

[m in sc]

drain the tank 1st. but that's a common issue. was the tank lined?