Miles to reserve

bikejunkie223 · December 03, 2008, 03:22:40 PM

Okay here is a question, I have noticed since the weather got much colder here I seem to have to switch my bike to reserve around 190 miles instead of the 225 or so in the summer, and i would think it's just using more fuel from extended fast idle warmups and whatnot except that when I fill it it only takes 3.7 gallons instead of the 4 and change from before. My mileage is unchanged (right around 59mpg) and the bike runs exactly the same as it always has (only has 5500 miles) It just seems weird that when I get to 180-190 miles on the tank the bike starts surging ever so slightly, and switching to reserve makes it stop. It's odd that the same thing used to happen at 220-230 miles in the summer. It's like someone shrunk my fuel tank by .5 gal when I wasn't looking, and no there aren't any dents or anything that would cause that so if anyone has an explanation I'd love to hear it.

Also, where I buy my fuel makes no difference in this symptom. it's the same regardless of fuel brand.

colorider · December 03, 2008, 03:47:32 PM

That issue seems to be fairly common with these GS bikes and some people see a much more dramatic diffeene than you are seeing. There are a lot of threads on the same issue. My bike does it. My current opinion is that it is related to the fuel petcock - they tend to have problems. I'm doing a test right now on my bike -changed my fuel petcock to work without vacuum. I'm hoping that will cure it so I can use my full tank. I was only getting 120 - 160 miles before I had to switch to reserve. The problem with my test is that it's codl and I don't ride that much right now - takes a while to get through a tank.

Mdow · December 03, 2008, 04:04:04 PM

this about the choke your having to use to get the bike started and warmed up thats were you gas is

Bluesmudge · December 03, 2008, 04:35:44 PM

Make sure you are filling the tank up all the way -- the same way -- each time. You will get the most miles out of a tank if you fill it up on its centerstand.

qwertydude · December 03, 2008, 08:59:18 PM

Extra choke burns lots more gas and not to mention longer warmup times. Time spent warming up wastes gas as heat is robbed from the combustion process to heat the engine instead of expand the combustion gasses. While colder oil is thicker and parts are tighter, further wasting gas due to friction. Chains are stiffer because of the cold stiffening the o-rings. All these combine to lower gas mileage in the cold. I normally get 240 miles to reserve in summer. Now I only am getting 220 miles to reserve. Mine's so high because of my 18 tooth front sprocket.

bikejunkie223 · December 04, 2008, 07:58:50 AM

Right, I fill the tank the same way every time while I am sitting on the bike holding it level- my point is I'm not seeing any lower fuel economy- it doesn't seem to be using any more gas, it just makes me switch to reserve sooner to run properly and when I fill up it takes less fuel to fill. it's just weird.

colorider · December 04, 2008, 08:43:12 AM

Let me explain my opinion about the petcock a little further. When the fuel petcock gets older (or maybe gets cold in the winter?) the diaphram can get stiff or the check valve can get partially clogged. That will cause fuel to flow a little less efficiently through the petcock and the head pressure (fuel level) in the tank can become the limiting factor in fuel flow. As the tank empties, it more quickly comes to the pont where it can't push enough fuel through the petcock and lines. By switching to reserve the head pressure is increased and fuel can flow again.

I'm not certain but that's my workng theory.

bikejunkie223 · December 04, 2008, 03:24:17 PM

Sounds plausible to me, except my bike is an '07 with 5300 miles on it, but I suppose the cold could be stiffening up the rubber diaphragm...

colorider · December 04, 2008, 04:42:06 PM

You're probably right, with a new bike it is likely the cold causing it. Probably not gunk or aged parts that an older bike would have. It woudl be interesting to know if your miles to reserve goes back up when the weather gets warm. Where are you located?

lilwoody · December 04, 2008, 07:56:57 PM

My 05 has done the same thing and I live in sub tropical Florida. It started on my wife and I's last trip to Kew West. I had to go to reserve at 210 miles and it took 3.7 galolons (56.7 mph). The last trip we made there I went to reserve at 240 and it took 4 gallons (60 mpg). The milage was lower on the last ride due to Floriduh going to E10 (10% ethanol) but that still doesn't account for the reduce fuel. It has continued to only take 3.6 to 3.7 gallons when it hits reserve ever since. To me it's no big deal, it's just a thing.

bikejunkie223 · December 04, 2008, 10:40:36 PM

Quote from: colorider on December 04, 2008, 04:42:06 PM
You're probably right, with a new bike it is likely the cold causing it. Probably not gunk or aged parts that an older bike would have. It woudl be interesting to know if your miles to reserve goes back up when the weather gets warm. Where are you located?

I'm in Oregon so it likely won't warm up till spring, but if my mileage till reserve goes back up I'll be sure to post- assuming I don't buy the '07 Honda 25th Anniversary Interceptor I saw at the shop today. My heart has been filled with lust.

News:

Miles to reserve