Petrol consumption suddenly dropped...

[Finbarr]

Hey folks - usual routine, fillup with gas right up to the top of the neck (I've drilled the filler flange thingy so that it breathes properly during filling) and wander off (after paying).

Normally, I get at least 60 or 70 miles before the first bar disappears on the fuel guage - but quite suddenly it's now gone after only 15 miles!

After looking inside the tank at this point the fuel has gone down a lot (so the guage seems to be accurate) and the fuel light is now coming on at 185 miles where before it was about 205~210.

Can't find any leaks anywhere...

My riding style is unchanged - I'm still doing the same daily route (30 miles each way per day commuting - mix of fast motorway and London traffic) and I have not had the bike in for any work, nor have I done any myself. Bike still has plenty of poke - no discernable problems I know of.

It's due its 12,000 mile service in a little while, still using about 150 mils of oil every 1000 miles, otherwise fantastic...

My only guess is possibly fuel filter needs replacement...

Thoughts?

Cheers,
Finbarr

 

[Steptoe]

nothing to do with fuel filter, if it popped you'd lose pressure and bike would be gutless wouldn't want to rev , if blocked same type of symptoms, have your CO reading checked -- you could always try changing up into 3rd gear and above

 

[adamski49]

Might be something amiss with one of the sensors that are needed to establish optimum fuelling (lambda probe for example).

I believe if one of these fails the chip defaults to a 'get you home' fuelling map which is richer than normal. This would lead to increased fuel consumption.

The BM diagnostic check might pick this up.

Adam

 

[Paul Wakefield]

Might sound daft but have you checked your tyre pressures? I got a slow puncture and the first really noticeable symptom (before the handling collapsed) was increased fuel consumption.

Paul

 

[Finbarr]

Thanks for the excellent advice!

I've just filled it up again, and I now suspect that the fuel guage is at fault.

After my previous post, the tank was showing near empty (no bars - but fuel light not on yet) and yet when I took the tank off to check connectors etc - there was heaps of gas still in it.

Having ridden it into London today and then filling it up to the brim - it all got rather interesting! - the top bar on the fuel guage never lit up at all.

Several cycles of the ignition made no difference - still on the station forecourt, tank full to capacity and the top bar was already unlit.

Time to have a look at the fuel sender methinks...

Is this a known something that goes wrong?

Cheers,
Finbarr.

 

[Mick_rw]

looks....

Having ridden it into London today and then filling it up to the brim - it all got rather interesting! - the top bar on the fuel guage never lit up at all.

Glad I read this post, on my last couple of refuels my top bar has not lit up even with the tank full, will have to watch this, having it serviced next week will ask them to check it out.

Mick

 

[MikeO]

Have a look at the multi-pin plug under the right hand side panel (the plug you have to disconnect in order to remove the tank). Problems with the fuel gauge are very often associated with corrosion to the contacts in the plug.....

Mike

 

[Rabbitson]

Finbarr, don't want to steal your post but could you eloborate on the drilling of the filler cap thing that you first mentioned? What is that exactly? (Presumably it's a cunning trick to allow you to get the last litre in more quickly? Sounds useful)

 

[Finbarr]

Mike O - Cheers, I searched a few other threads (should have done this first!) and found a little more detail on what you mentioned about the plug contacts.

I've cleaned the contacts with emery paper and everything is now working normally again.

Rabbitson - if you've got the same problem as I describe, on the right side of the tank under the black plastic cover you'll find a flatish black junction box for four wires coming out of the tank - it sits between the two fuel hoses. Clean the contacts on this and give a squirt with WD-40 - fixed it in 5 minutes flat.

Also - the filler-breather drilling thing is documented really well here: http://www.xs4all.nl/~hkuijer/filler.htm

He (Henry) has some other cool tips and tricks which can be viewed here: http://www.xs4all.nl/~hkuijer/

Thanks everyone for taking the time to assist and provide pointers to solutions.

Kind regards,
Finbarr.