Getting lower and lower and lower MPG each bloody time

[iMark]

Over the past few months my petrol consumption has went up quite a lot and I'm getting less and less MPG, I'm riding the same way I always do..

Brakes are fine, they aren't binding, I've cleaned the pistons and had new pads put in last month too.
Doesn't appear to be any breaks in the petrol hoses, or any signs of petrol leaking


https://i.imgur.com/X0Ftncu.png


Any ideas?

The bike feels like it's running fine apart from the odd misfire when idling (one of the coils is on its way out it seems)
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[mentalboy]

Have you checked the air filter recently?
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Make mine a Corona.

[iMark]

Not recently, I put a washable/reusable K&N one in back in mid October

It's just been declining slowly until last month really, then it started dropping quite a bit, but I was used to seeing 43-50 MPG in town and 50-60 on longer journeys

https://i.imgur.com/JlvsPo9.png
https://i.imgur.com/8N0hrUX.png
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[Northern Monkey]

[iMark]

I have short journeys yeah, but I've been doing the same journeys for 6 months.

The choke is only on for a short time to warm the bike up, it never affected it this bad last winter.
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[mentalboy]

Have you checked the ethanol levels in fuel recently - I did see a report about a fortnight ago about reduced mpg as levels increase, there's been a bit of a backlash in Florida recently because of this (as well as implied inferior internal protection). I don't know just how much difference it would make but my g/f's truck does get a better mpg when used in South Carolina, where ethanol levels are lower.

I'd still be inclined to give the K&N a good clean
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Make mine a Corona.

[iMark]

No idea what I would be looking at with that mentalboy

I always use the normal unleaded stuff from Tesco which is "RON 95" not tried the more expensive "premium unleaded" as I doubted it would make any difference with the ER-5.
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[doggone]

Cold mornings the oil is thick and things won't be running sweet until it has been going at least 10 minutes.
You could consider a thinner oil which is less viscous at low temps, it would be an interesting experiment anyway.

[Northern Monkey]

Without starting a boring as hell internet oil argument,

As long as the larger number is the same, you can drop to a thinner W grade with no loss in protection, so from 10w30 to 5w30 no problems.

[iMark]

oil is due for a change soon anyways, it was done between 2500-3500 miles ago... so maybe that will be a job after checking everything else when the weather decides to stop being retarded.
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[mentalboy]

[_Iain_]

Monitoring MPG this closely scares me.


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Please be aware that the above post may be full of complete nonsense.
Riding: '07 KTM Duke II, Baotian BT49QT-20 Driving: '88 Volvo 340

[iMark]

Took air filter out, clean as a whistle still.. nothing in the air box blocking the carb intake either.

@Iain I certainly notice when I'm only getting 80 miles to a tank instead of 100-120
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[P.addy]

[Northern Monkey]

[Robby]

You're burning 30% more fuel for the same journey, so something isn't right.

If it's a carbed bike I would be looking at the choke mechanism on the carbs to see if it is stuck on or fouling on something - I had that problem when I change the fuel tap for a pattern one, and the pattern tap was fouling the choke and holding it on.

The highest ethanol content you'll currently see is 5%. Ethanol has a lower energy content, but it still contains energy. The highest change in fuel burn you could expect to see using petrol with a 5% ethanol blend is 2%.

If it's a carbed bike then it's possible that the fuel tap isn't working and the needle valve in one of the carbs is knackered, letting some fuel seep past into the sump. Has your oil level gone up?

[ginny]

I'm having similar problems with my hornet.

My mechanical knowledge is equivalent to my black magic knowledge (in fact I think they might be the same thing) but I am considering that A) A dying/shite battery is causing it or more likely B) the plugs could do with changing. Its not feeling as responsive as before either.

This reply is supported by 0% knowledge and 100% guesswork, but hey, maybe the plug thing might not be far off?

[iMark]

Oh my fuel tap works on both the ON and RES position never bothered with the PRIME position, just had to use reserve earlier before getting petrol as it was dying "ON", and it was running fine after putting it on "RES"

I've already had a fiddle with the choke slide mechanism on the carb, doesn't appear to be getting stuck, it's returning fully when resetting the choke lever position on the handlebar.

If the choke was being stuck on my idle would be higher than usual as that is all my choke seems to do, chokes the engine unless you give it a little bit of throttle (if you try turn the choke on when the bike is running, it'll stall basically) byt then revs increase from idle to around 3k normally when cold then close to 4k when warmed properly.

Choke does help the bike start then raises the idle, same happens when I push the slider manually (apart from the fact it will stall that way unless I do it really slowly or give it a little bit of gas while the bike is running, can't really test that with the engine off hah)


Bike has just had a new battery I don't think that's relevant to MPG decreases though:?:

Plugs are fine, they are a nice tan/brown colour both at idle and running (bike is running a wee bit lean though cus of the exhaust and air filter)
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[Codemonkey]

What state are the chain and sprockets in ? Tyre pressures OK ?
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Test Passed 10/05/2011 Current bike: XJ6-N

[Kickstart]

Hi

That is a hell of an increase in fuel consumption. The K&N could have something to do with it (presume it is a fuel injected bike with feedback from the lambda probe to sort out the mixture - and detecting a weak mixture it could richen it up), but not that much. Same if the air filter wasn't seated correctly.

However looking at those figures you are doing a fairly limited mileage (and possibly less now it is colder). When cold the bike will richen the mixture itself (again assuming fuel injection) and use more fuel. Seems you might be doing 10 miles a day at times, which could be 2 5 mile journeys, most of each of those journeys with a cold engine and a rich mixture. Or you could be leaving it to warm up for a while before riding off.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[iMark]

Chain and Sprockets are fine, they're near enough brand new still, not even needed adjusting once yet.

Tyre Pressures were checked a few days ago, both are fine they were only out a few PSI each, both back to normal now.

The bike is Carb not FI Kickstart.
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[27cows]

Most common cause of a drop in mpg is the bike running rich. Am guessing that is the case here.

Either that or some thieving herbert is having some of your juice away
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The RXS100: vehicle of choice for Chuck Norris

[iMark]

The spark plugs look fine, maybe a bit light but they are definitely a tan/light brown colour (I'm colourblind so.. yeah..), both idling and running (Cutting engine out mid RPM then removing plugs).

If anything I'd expect the bike to be running a bit lean due to the air filter and exhaust (These were put on a few weeks prior to the noticeable drops in MPG)
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?

[mentalboy]

Sounds to me like it's time to have a look in the carbs and see if there's any muck in there. Re. earlier oil level question - any sign of fuel getting in there?
____________________
Make mine a Corona.

[iMark]

the oil doesn't smell like petrol... if that's what you''re asking

Smells funky but not petrol.
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K8 GSXR 1000
"G" : you got him to have a look at a forum which seems to have established a picture of an erect penis in a cat's mouth as it's mascot and thought he might consider it ok?