Best speed/rpm for fuel economy? GS850

[Burque73]

A friend and (former?) GSR member named Raygun put a G tank on his 1100L. Search for posts by him. Maybe he wrote something up about it.

[Rob S.]

I just dropped in to say that generally, if you're worried about fuel economy on a motorcycle, you're doing it wrong...

Anyway, you can happily flog an 850 at 6,000+ RPM for hours and hours on end. I've done it many times because I live a long way from the mountains. These engines love to rev, they need to rev. Grip it and rip it. It won't hurt a thing. Learn to love that groovy rush between 6,000 rpm and redline.

However, a motorcycle with a rider on top is an aerodynamic disaster,

Here, here!

In the third world, they ride motorbikes for economy. Here, we ride bikes because they're cool. You meet the nicest people...

But I grew up slightly priveledged. I also grew up when gas was less than a buck. I recall 35 cents a gallon.

I remember once sitting in the family's station wagon, a 1966 Oldsmobile Vista Cruiser. Dad put her in Park and said he'd be right back, he had to get something from our 6th floor apartment.

"You're going to leave it running?" I asked. "Won't that waste a lot of gas?"

"No," he told me. "It'll use more gas to restart it." So my die was cast.

Every time I've brought a vehicle in for work, I've told the mechanic, "Fuel economy doesn't matter. If you can make it a hair faster, I don't care if it uses twice the gas."

And about revving it? My biggest fear is that my little brothers will die before they experience a big bore Jap four near redline.

[Burque73]

Here's the thread I was referring to.

https://www.thegsresources.com/_forum/showthread.php?239742-G-tank-on-my-L

Apparently the G tank, triple clamp and forks were taken from a parts bike. I remember Raygun saying he used a length of allthread through the frame and fabricated some rubber nubs on the ends for the tank mounts.

[Steve]

If only I could put a larger tank on my L.

Do you think with some ingenuity and a welder the G tank could be retrofitted to my L and turn out half way decent?
Using the front mounting point to avoid fork contact? Although I suspect I'd have seat problems then since the tank is longer... Hmm....

A friend and (former?) GSR member named Raygun put a G tank on his 1100L. Search for posts by him. Maybe he wrote something up about it.

I have not read through Raygun's post, but about the only way to get things to play together would be to fabricate your front mounts (you can see where they would be on your L frame) and put the tank in place. To keep the forks from hitting, you would need to replace the forks and triple clamps with parts from a G.

There might be a slight fitment issue at the seat/tank interface, but it shouldn't be too bad. I would have to take the seat off my wife's L and place it on my frame to see how (if?) the angles match.

.

[93Bandit]

Here's the thread I was referring to.

https://www.thegsresources.com/_forum/showthread.php?239742-G-tank-on-my-L

Apparently the G tank, triple clamp and forks were taken from a parts bike. I remember Raygun saying he used a length of allthread through the frame and fabricated some rubber nubs on the ends for the tank mounts.

Thanks for the link! I'll have to look at both my bikes to see what it would take to do the swap.

I have not read through Raygun's post, but about the only way to get things to play together would be to fabricate your front mounts (you can see where they would be on your L frame) and put the tank in place. To keep the forks from hitting, you would need to replace the forks and triple clamps with parts from a G.

There might be a slight fitment issue at the seat/tank interface, but it shouldn't be too bad. I would have to take the seat off my wife's L and place it on my frame to see how (if?) the angles match.

.

I think I have all the parts I would need. I hate tearing up my L though. I finally got it running and would like to enjoy this season. We'll see.

[raygun]

So I suppose I'll resurrect my account for this. Just to prove the naysayers wrong, you can and I did put a G tank on my L. It fit pretty well actually. The front required cutting off the existing mounts for the tank (where the rubber bumpers sit) and either relocating those mounts up the neck with a welder or using a piece of allthread, nuts, and washers to make up new mounts. The rear was the simplest, I think I used a piece of chain to pull the tank down onto the frame and put a piece of rubber between the frame and tank. I think someone with more ability, creativity, and tools could fabricate up a bracket. I no longer have the bike nearby but still own it. I'll try and get some pictures and measurements when I get a chance but for now I've got some very crude drawings that might help. I personally believe this is a very simple modification and possibly reversible with a welder. Of course, you will have to use the G forks and triple clamp. I don't remember about the wheel and the bracket for the brakes. I ended up using the G wheels I had because I liked them better. I didn't want my bike to be out of commission so I rebuilt the G forks and got everything ready for the swap which I did in one day. The bike was a 1982 GS1100GL and the donor bike was a 1980 GS850G. Sorry for the super large images. I have no idea how to resize.

[Steve]

Raygun, nice to see you drop in.

I see that you have an '80/'81 G tank on your '81 L. I see now why you had to use a chain on the rear mount. The G tank uses a single horizontal bolt, the L uses two vertical bolts.

I am wondering if it would be possible to bolt an angle bracket to the L frame locations that would have provision for the bolt on the G tank. Maybe even reverse the hardware. Use that vertical tab to capture a bolt that is being used more like a stud. Slide the tank onto it from the rear, then use a washer and nut to hole it there.

.

[raygun]

I think it would definitely be possible with the right tools and skills. I didn't have either at the time (and probably still don't). I do understand that 93Bandit would hate to take apart a running motorcycle but with some careful planning and preparation, I think the whole swap could be done in an afternoon. I think I also had to enlarge the holes for the fender to get it to fit.

[93Bandit]

I think it would definitely be possible with the right tools and skills. I didn't have either at the time (and probably still don't). I do understand that 93Bandit would hate to take apart a running motorcycle but with some careful planning and preparation, I think the whole swap could be done in an afternoon. I think I also had to enlarge the holes for the fender to get it to fit.

Hey, thanks for adding to the thread! I like your idea of getting everything ready for the swap beforehand. That would definitely reduce down time.

[raygun]

Hey, thanks for adding to the thread! I like your idea of getting everything ready for the swap beforehand. That would definitely reduce down time.

Not a problem. I'll try and get some pictures of the bike when I get a chance. If you need any help, feel free to get my contact information from Burque73.

[Burque73]

That's really cool to see you drop in, raygun. I'm looking forward to seeing that L/G hybrid bike in the hills near Silver City in a few weeks. Or will you ride the KZ? In any case, it'll be great to hang out and ride.

In regards to the OP's interest in RPM and fuel economy, I'm with Grimly. Keeping both needles pointing straight ahead seems to be a symmetry that not only the rider, but the bike responds very well to. YMMV....literally, lol.

[93Bandit]

Not a problem. I'll try and get some pictures of the bike when I get a chance. If you need any help, feel free to get my contact information from Burque73.

More pictures would be great! I may contact you to pick your brain sometime, if I decide to go that route. I appreciate it!

That's really cool to see you drop in, raygun. I'm looking forward to seeing that L/G hybrid bike in the hills near Silver City in a few weeks. Or will you ride the KZ? In any case, it'll be great to hang out and ride.

In regards to the OP's interest in RPM and fuel economy, I'm with Grimly. Keeping both needles pointing straight ahead seems to be a symmetry that not only the rider, but the bike responds very well to. YMMV....literally, lol.

YMMV?

[Burque73]

YMMV?

Phrase[edit]

your mileage may vary

1. (idiomatic, often computing) It may work differently in your situation, or be different in your experience. quotations ▼The battery lasts a day in my phone, but your mileage may vary.
2. (idiomatic) Used to express a possible difference in taste: this is just my opinion, your opinion may be different. quotations ▼I think that red dress looks really good on you, but your mileage may vary, of course.
   

Synonyms[edit]

• initialism: YMMV

[raygun]

That's really cool to see you drop in, raygun. I'm looking forward to seeing that L/G hybrid bike in the hills near Silver City in a few weeks. Or will you ride the KZ? In any case, it'll be great to hang out and ride.

I'll be on the KZ. The GS is in storage in Utah but my little brother may start riding it here pretty soon. I hope we're going! You'll have quite the trip summary for the guys here.

[Wingsconsin]

I have an '83 L 850 -
My fuel economy ranges from 37 to 45 MPG all the time with the average being 42

I stop around 125 -135 miles to add fuel at nearly any speed up to 75 mph
At that point I buy from 3.2 to 3.5 gallons of fuel -
IF Steve is correct I still have about 1 gallon +/- a bit -
I am just fine with that -- many times I hit the reserve at my fill up target of 125-135 miles
I have seen 150 miles once - but that is cutting it closer than I prefer -
Every 125ish miles is a good time to stop and stretch my legs --
If I want to go for a LONG run -- I will take the Goldwing and go 250 miles tank to tank