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The 2-Stroke Garage => General Chatter => Topic started by: bheezy27403 on October 25, 2021, 10:19:09 AM

Title: Gas tank volume
Post by: bheezy27403 on October 25, 2021, 10:19:09 AM
 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.
Title: Re: Gas tank volume
Post by: m in sc on October 25, 2021, 10:26:27 AM
i typically get to reserve at about 2.5  gallons used.  us models are all the same sized tanks 73-75.

Title: Re: Gas tank volume
Post by: bheezy27403 on October 26, 2021, 10:45:47 AM
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.
Title: Re: Gas tank volume
Post by: m in sc on October 26, 2021, 10:59:01 AM
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.    :twocents:

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.
Title: Re: Gas tank volume
Post by: bheezy27403 on October 26, 2021, 12:14:44 PM
Thanks Mark.  I'll just be sure to not get too deep in without some sort of back up plan.
Title: Re: Gas tank volume
Post by: soonerbillz on October 26, 2021, 01:18:01 PM
So being ultra conservative maybe a hundred miles per tank?
Title: Re: Gas tank volume
Post by: Striker1423 on October 26, 2021, 01:27:43 PM
I subscribe to the "100 mile club" on the RD. That means look for gas around 100 miles or prepare to walk.
Title: Re: Gas tank volume
Post by: m in sc on October 26, 2021, 01:31:31 PM
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?

Title: Re: Gas tank volume
Post by: Striker1423 on October 26, 2021, 02:12:10 PM
I agree, you should get around 15-20 miles or so before reserve is gone.
Title: Re: Gas tank volume
Post by: pidjones on October 26, 2021, 03:52:08 PM
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!
Title: Re: Gas tank volume
Post by: bheezy27403 on October 26, 2021, 05:23:48 PM
Quote from: m in sc on October 26, 2021, 01:31:31 PM
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?
Title: Re: Gas tank volume
Post by: Striker1423 on October 27, 2021, 07:00:17 AM
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.
Title: Re: Gas tank volume
Post by: m in sc on October 27, 2021, 07:45:04 AM
exactly. there are 2 nipples under tank, neither should go to a carb, but connect to each other. 
Title: Re: Gas tank volume
Post by: bheezy27403 on October 27, 2021, 09:30:00 AM
Yes it's there. I'll take it off tonight and inspect it to make sure it's not clogged.
Title: Re: Gas tank volume
Post by: m in sc on October 27, 2021, 10:09:45 AM
drain the tank 1st. but that's a common issue. was the tank lined?
Title: Re: Gas tank volume
Post by: bheezy27403 on October 27, 2021, 12:13:07 PM
No. She's spic and span
Title: Re: Gas tank volume
Post by: bheezy27403 on October 28, 2021, 01:57:26 PM
Quote from: m in sc on October 27, 2021, 10:09:45 AM
drain the tank 1st. but that's a common issue. was the tank lined?

It's got a pretty good "sag" in it.  Should I flatten this slack so it's closer to the tank bottom?
Title: Re: Gas tank volume
Post by: m in sc on October 28, 2021, 02:17:42 PM
that wont affect it since fluid always seeks its own level. aesthetically, yeah its a bit much but no problems functionally. are both ends clear and flowing?
Title: Re: Gas tank volume
Post by: bheezy27403 on October 28, 2021, 02:24:50 PM
Quote from: m in sc on October 28, 2021, 02:17:42 PM
that wont affect it since fluid always seeks its own level. aesthetically, yeah its a bit much but no problems functionally. are both ends clear and flowing?

Tube was fine.  The nipple out of the tank seems less than ideal which would cause the problem. Is there a screen or filter above it in the tank or can I run something up through it to punch it out?
Title: Re: Gas tank volume
Post by: bheezy27403 on October 28, 2021, 02:28:41 PM
Both are clear now.
Title: Re: Gas tank volume
Post by: m in sc on October 28, 2021, 02:30:33 PM
no screen. just a tube welded tot he bottom of the tank. use a small wire and get it to flow.  welding wire works well, or a small detail 'gun style' brush

Title: Re: Gas tank volume
Post by: bheezy27403 on October 28, 2021, 02:35:20 PM
Quote from: m in sc on October 28, 2021, 02:30:33 PM
no screen. just a tube welded tot he bottom of the tank. use a small wire and get it to flow.  welding wire works well, or a small detail 'gun style' brush

How bout weed whacker string? :clap. She flows both sides tube is clear (and shortened) we'll see when she hits reserve next time.  Fingers crossed.  Thanks for the help.
Title: Re: Gas tank volume
Post by: bheezy27403 on November 10, 2021, 08:32:05 PM
Quick update. A couple days ago I hit reserve at 85 miles so yesterday I head out armed with a water bottle of gas to see if my inspection and subsequent finding of a slow flow on the right side crossover nipple was the culprit. Remember I only got about 8 miles before she gave up the first time I hit reserve. I rode over near my local non-ethanol station and put some miles on her staying close in case of emptying. I pulled in at 101 on the tripometer with some still in the tank so it seems I have remedied the situation. Thanks for all the help.