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Hi

i own a VFR800X 2013. 
it’s had a few owners, and has covered 12,000 miles, 2,000 miles in my hands. 

modifications done:

1: pair valves disabled and blocked, air box bunged. 

2: flapper valve disabled / disconnected 

3: arrow end can ( all done by first owner )

4: O2 eliminator fitted, exhaust plugged. ( by me )

5: Previously fitted K&N air filter (clean) and new spark plugs ( by me )

6: Hyperpro shock and fork springs ( by me )

7: Handlebar conversion to Renthal bars ( I just hated the plastic shrouds )
 

previous owner also balanced starter valves, no idea how well, but other work seems competently done. Bike sounds fine, nice even beat when warm and the fuelling seems fine. Smooth even power delivery, no hesitancy or snatchiness. 


I was getting 6.1 miles per litre commuting in London ( heavy traffic )

 

The exhaust also smelt very rich at start up. Lots of white steamy clouds in winter temperatures. 
 

I recently fitted the O2 eliminator as the O2 sensor looked very sooty in the hope it would address the rich mixture. 
I then got 8.1 miles per litre. Happy days. 
It has since started heading back towards the previous figure. Now at 6.8 miles per litre. The weather has improved, so some of this might be happy throttle related. 

I’ve run seafoam in the tank twice also, in case it cleans up the injectors. 
 

My questions are

1: What is a normal fuel consumption figure for this engine when city commuting?

2: If its uncharacteristically low, what might be causing it? I don’t drive like a madman. 
3: Where is the fuel pressure regulator on this bike? It’s not on the fuel rail, like on previous models. 
4: could it be the MAP sensor or thermostat?

5: could it be a dripping injector issue and they need ultrasonic cleaning?

6: am I chasing ghosts and these engines are just very thirsty 😉

 

thank you for any help or information 

 
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Are you using Ethanol blended fuel? Your VFR can't advance the timing to optimize fuel burn with the higher octane, and as Ethanol fuel has a lower calorific value compared to straight gasoline your fuel economy therefore is not as good?

 

By adding O2 sensor eliminators, how do you know you are getting the optimal A/F ratio?

 

Cold start "white steamy clouds" would suspect as normal condensation, provided it disappears when the engine is warm, might also be worse with Ethanol blended fuel.

 

Make sure that with the "Flapper Valve mod" the main vacuum hose has been properly blocked off.

 

If your 2013 VFR800X is similar to the 2014 VFR800F there is no Fuel Pressure Regulator as per previous gens.

 

A MAP sensor issue should flag a Diagnostic Trouble Code if it is faulty. And any issue with your Thermostat should indicate a change to its normal running temperature. Or be much slower to warm up if in the open state.

 

For a bike only having done 12,000 miles I'd be surprised if it had a leaky injector.

 

Also the 800X is more upright so probably has greater wind drag, than the 800F.

 

Recent fuel economy check on my 2014 8gen.

4.02ltr per 100k's =

4.02ltr per 62.137miles =

15.46 miles per Litre.

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What was the intent / goal of fitting an O2 eliminator? 

 

 

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9 minutes ago, Cogswell said:

What was the intent / goal of fitting an O2 eliminator? 

 

 

 

Looks like OP has duplicate threads running in parallel ....

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Hi

thanks for your replies. 

I put the questions in 6th gen and 800x forums in the hope of getting views from both groups of owners. 
if that’s a bad idea, happy to delete one of them. 
 

Grum- I use 98 octane fuel in UK. Apparently 95 octane fuel contains 5% ethanol, but there’s no requirement in UK for 98 to contain any ethanol. 

The O2 eliminator is supposed to tell the ECU to deliver optimum fuel ratio or am I wrong on this. They are used for aftermarket exhausts and power commanders ( I don’t have a PC though )

 

Cold start steam- does disappear after warm up and is considerably less now ambient temp has risen. But still smells rich. ( makes me gag if I get a nose full, first bike in 30 years riding that has done this to me. It just doesn’t smell right ) 

 

Flapper mod is plugged correctly 

 

good to know about MAP sensor 

 

Thermostat- 
The bike warms up and steadily gets up to 82 before it sits there for a while, then it starts to slowly head up to 102 before the fan kicks in and drops to 96 when the fan shuts off again. Then it repeats this cycle of 96 to 102 and back down again etc

It does waver slightly around 80 going up and down before settling. 
The top of the RHS radiator does start to feel warm around 62 degrees, not hot, but warming. Could this indicate a stuck open stat? 

 

wind resistance doesn’t seem to be a causal factor at commuting speeds. 
 

Fuel pressure is regulated directly by the pump then??

I was getting 27mpg before the O2 eliminator was fitted. Which seems very low. 
straight after fitting it went to 38mpg. 
 

I was thinking if the bike has only covered 12,000 miles in 8 years, it must have sat unused in various garages for extended periods of time with fuel going stale in the injector bodies and tank. 

 

 

 

Cogswell- I fitted the O2 eliminator in case the sensor was malfunctioning and causing the over rich fuel mixture. When I swapped the plugs the originals were fairly black, sensor was very sooty also. 
I don’t have an exhaust gas analyser, so was a fairly cheap test to see if it made a difference. 

 

 

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For reference- my commute rarely sees me get above 50mph and mostly its filtering past heavy London traffic. 
Vtec use almost impossible during the trip. 
Even if I change up and really potter along, consumption remains the same. 
I guess I need to do a longer run on Dual carriageway and motorways to see what the figure is then for a decent comparison. 

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1 hour ago, Magneto said:

Bike can’t be run that way. You must include Italian tune-up in your riding routine....

??? You’ve lost me there

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9 minutes ago, Magneto said:

As it says “modern fuel injection has rendered this technique obsolete” I’ll stick with a slow and steady test. 
Don’t get me wrong, I enjoy the engine when I can. I love this bike. I just want to make sure she’s running right. 

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The O2 Lambda sensors measure the exhaust O2 or lack there of. An O2 eliminator sets the ECU to run the engine on a preprogrammed fuel table. As this appears to have improved the fuel flow, it would imply the engine was running rich due to failed O2 sensor.

 

The sooty O2 sensor is likely due to over rich state caused by continuous cold running, failed thermo stat or dirty air filter. 
 

8.1MPL is 36mpg Imperial (UK) which is normal for the type of riding you describe. I've generally recorded 35-40 MPG over many years of mixed riding & touring. Its one of the drawbacks to the VFR engine, it doesn't change its mpg much regardless how you ride it. Though I have had 21MPG on track days. 
 

I'd suggest you check the basics & if they are OK. Take the bike to a dyno & they can measure the O2 under load & give you an air fuel readout for the whole rev range. 
 

I have my 5th gen set to 14.2/1 AFR, and I get 44MPG during mixed speed riding. 
 

YMMV

 

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4 hours ago, Mohawk said:

The O2 Lambda sensors measure the exhaust O2 or lack there of. An O2 eliminator sets the ECU to run the engine on a preprogrammed fuel table. As this appears to have improved the fuel flow, it would imply the engine was running rich due to failed O2 sensor.

 

The sooty O2 sensor is likely due to over rich state caused by continuous cold running, failed thermo stat or dirty air filter. 
 

8.1MPL is 36mpg Imperial (UK) which is normal for the type of riding you describe. I've generally recorded 35-40 MPG over many years of mixed riding & touring. Its one of the drawbacks to the VFR engine, it doesn't change its mpg much regardless how you ride it. Though I have had 21MPG on track days. 
 

I'd suggest you check the basics & if they are OK. Take the bike to a dyno & they can measure the O2 under load & give you an air fuel readout for the whole rev range. 
 

I have my 5th gen set to 14.2/1 AFR, and I get 44MPG during mixed speed riding. 
 

YMMV

 


 

interesting Mohawk,

 

Air filter is spot on

 

I am starting to suspect the thermostat. I ordered a used unit for £10 basically for the housing as an insurance measure in case I have trouble opening the one on the bike currently and have a new actual stat and o ring on the way. 
I might try this before committing to a Honda dealer inspection and basically allowing them to empty my wallet. It’d be far more satisfying to sort it myself. 

 

As an update,  I went out for a nice steady run today with more open roads and some motorway miles. Filled up and zeroed everything at edge of city stuff. 
The best I saw was 10.4 miles per litre average on the dash. In 27.2 miles, consuming 2.6 litres. That’s about 48.5mpg
As I came back into traffic it started to drop down as you’d expect. But wasn’t going for long through traffic and it finished up reading 9.2 m/l average. 
 

Before setting off initially I let her warm up and the radiators were definitely getting warm at around 76 deg centigrade. The temp went up and down a bit by 1 or 2 degrees before reaching 80-82 when I set off. 
The temp when on the motorway travelling at 70-80mph sat pretty steadily at 76 deg and only climbed up when in traffic. 
Does that sound normal or should it be holding a higher operating temp of around 82-84 when in use. 
 

O2 eliminator still in place. 

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Searching through other posts I found something that rang a bell. When I bought the bike I remember it had a slight milky deposit in the oil window. 
it disappeared quickly and hasn’t returned but......it’s all starting to point to a thermostat that is stuck open. 
 

poor mpg, rads warming too early, low running temperature, and now this ⬇️

 

B4DBCB05-EC4B-43CC-BD61-7A0F5FB9D7B3.png

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6 hours ago, Bikespod said:

As it says “modern fuel injection has rendered this technique obsolete” I’ll stick with a slow and steady test. 
Don’t get me wrong, I enjoy the engine when I can. I love this bike. I just want to make sure she’s running right. 

 

IT  is not a testing technique mate. That one you need to go nice and easy to see what fuel mileage is.

What I meant, during your normal course of riding you need to have periods where you push the engine to clear it up. I would say once a week minimum. Easiest way is expressway and make engine nice and toasty.

As far as Italian Tune-up being obsolete, wishful thinking...

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Believe me, if I had a route to work that involved fast roads I would be exploring more of the Rev range. Our capital cities roads are clogged with cars, dotted with speed cameras and filled with potholes you could lose the front end in. They are in a truly embarrassing condition. Add in drivers that either don’t care or are too stoned to notice you and you can imagine the consequences of excessive speed. That said, it was nice to get out on faster roads and I do need to do it more. 

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On 4/2/2021 at 10:27 PM, Grum said:

 

 

If your 2013 VFR800X is similar to the 2014 VFR800F there is no Fuel Pressure Regulator as per previous gens.

 

 

 

His bike is based on the 02-13 6th Gen.

 

Just seen this thread, some good advice and glad to see yr getting out of the smoke for the odd blat. Yr more than welcome to come up to sunny Herts (J10 of the A1) when the cafes reopen for a blat around some nice roads.

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34 minutes ago, Skids said:

His bike is based on the 02-13 6th Gen.

Ok. Thanks for the heads up Skids.

So therefore the Fuel Pressure Regulator is located on the Right side end of the forward fuel rail. NOT like the 8gen.

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4 hours ago, Magneto said:

What’s “blat” Skids?

Funny...... Over here if you were catching up for a "blat" you'd be sharing a Bacon Lettuce Avocado Tomato toasted sandwich together!!!:laughing6-hehe:

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yw, my wife is British and we get word meanings mixed up all the time!!! 😉

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