Fuel range after fitting 6mm shim

Nutter67 · 04-18-2008, 2:11 AM

After I fitted the 6mm shim to my bird (great mod, totally different feel), I noticed that my fuel range - to the flashing light - has dropped by 40km. It is now down to 230-235km. As soon as it starts flashing this time I will try to get to the servo asap to see how much fuel actually goes in.

I know that the shim will add something like 30-35mm to the seat height, which will affect the "level" of the fuel in the tank. Would this affect the fuel level sensor?

Just had the bike to the stealers for its 6000km service, they checked the fuel system, balanced the intakes and couldn't find any other reason for the drop in mileage.

IrishXX · 04-18-2008, 3:09 AM

Probably coz your hammering around the corners faster, haha!

X1rider · 04-18-2008, 6:53 AM

Could be the float sending a false signal to the sensor due to the different ride height. If the XX uses the old style arm float, it is a simple matter to bend it down a bit like I did on my 86 FJ1200. But I think the FI bikes use a different set up. Just get a new fuel pump base gasket before taking everything apart though. Or use this site to have a look at the fuel system:
www.worldofpowersports.com

X1rider · 04-18-2008, 6:56 AM

Nope, no arm float. Good web site for pictures though.

DragonXX · 04-18-2008, 7:19 AM

................. This is Twilight Zone stuff mate !

RodeRash · 04-18-2008, 9:33 AM

Could be a coincidence. Remove the shim and see if it changes back.

lois · 04-18-2008, 10:03 AM

I wonder if the Bird uses a "thermister" to measure fuel level.....if so, that would also need to be adjusted.

EDIT....nope, checked the online fiche, the Bird uses a float. It appears to have a fairly long arm on it, which could explain the big variation.

Warchild · 04-18-2008, 10:43 AM

Quote:

Originally Posted by Nutter67

I know that the shim will add something like 30-35mm to the seat height

Is this accurate?

I've had the 6mm shim before, and I don't seem to recall it raising the seat height quite that much.... 35mm is just shy of an inch and a half; that's a pretty good jump in height....

lois · 04-18-2008, 11:11 AM

Quote:

Originally Posted by Warchild

Is this accurate?

I've had the 6mm shim before, and I don't seem to recall it raising the seat height quite that much.... 35mm is just shy of an inch and a half; that's a pretty good jump in height....

I was thinkin the same thing......may be installed a 60MM shim by mistake...

birdpilot · 04-18-2008, 6:48 PM

The same thing happened to my 06 bird when i put the shim in.The thing is though the bike is actually using more fuel which makes no sense at all.

lois · 04-19-2008, 6:12 PM

Hey Warchild.....I'v been thinking about this, the 6mm shim can't effect gas mileage.....how could it. All your doing is raising the rear of the bike an inch. But, by doing that, the tank will be sitting slightly down hill on the bike which would definetly change the position ( calibration) at which the reserve point for the float would be at.

The bike still carries the same amount of fuel, your range wouldn't change, but the angle of the float would cause the reserve light to come sooner/ later...and your fuel gauge will not indicate correctly.

are ya pickin up what I'm layin down?

Nutter67 · 04-19-2008, 10:27 PM

Quote:

Originally Posted by lois

Hey Warchild.....I'v been thinking about this, the 6mm shim can't effect gas mileage.....how could it. All your doing is raising the rear of the bike an inch. But, by doing that, the tank will be sitting slightly down hill on the bike which would definetly change the position ( calibration) at which the reserve point for the float would be at.

The bike still carries the same amount of fuel, your range wouldn't change, but the angle of the float would cause the reserve light to come sooner/ later...and your fuel gauge will not indicate correctly.

are ya pickin up what I'm layin down?

Thanks Lois,

Thats what I was trying to say, but my brain got tongue tied.....

Nutter67 · 04-19-2008, 10:32 PM

Quote:

Originally Posted by Warchild

Is this accurate?

I've had the 6mm shim before, and I don't seem to recall it raising the seat height quite that much.... 35mm is just shy of an inch and a half; that's a pretty good jump in height....

I didn't measure before and afters, but I read something about this somewhere (either here, OzBB or IXXRA) that the shim raised the seat height by this amount. After fitting the shim, the bike certainly feels at least that much taller (and stiffer as well).

Unfortunately work and an overtired 3yo are preventing me from going out to the garage and removing the shim to get some base line readings.

Banshee · 04-20-2008, 7:53 AM

Well, yes. The shim raises the height at the dogbone by 6mm, follow this to the end of the swingarm, (assume 6" from pivot to shock, then 18" from shock to axle), that would be 24mm. And I haven't accounted for the effects of the dogbone there, just leverage...

Regardless of that, you are probably just riding harder now it handles better, you Nutter, you!

DragonXX · 04-20-2008, 7:31 PM

Quote:

Originally Posted by birdpilot

The same thing happened to my 06 bird when i put the shim in.The thing is though the bike is actually using more fuel which makes no sense at all.

The 6mm shim should not affect consumption at all ! ................ It may affect the gauge but not actual consumption !

But can I make a suggestion .................
Maybe you cowboys are riding the 'Bird harder because she feels like a sports bike after the mod

flblackbird · 04-20-2008, 8:46 PM