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Honda CBR xx Blackbird, fuel consumption issue


Vic101
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Hi All,

My bike has a problem drinking way to much petrol, and it also has a carbon build up on the exit of the exhaust pipe, so it's not burning fuel efficiently. It's a 1999 one of the first fuel injected versions. I have the owners and workshop pdf's but didn't really find much that would lead me down the right path apart from maybe the air flow has been compromised (might just need a new air filter) or blocked injectors and the net wasn't much help. So here I am to ask if anyone else has had similar issues? I don't want to start taking it apart and spending money I don't have if its something simple, like an air filter.

thanks for looking regards Vic

PS. Not had the Bike long so I haven't got around to doing much apart from LED head light's

 

Edited by Vic101
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Doubt it blocked jectors especially if its still running smoothly, also looking at the condition of the spark plugs will give you a clue what and which cylinder (if anything at all) are to look at. If one plug is wetter or blacker than the rest then that cylinder needs attention.

similar if you have a thermo gun and measure the heat from each cylinder partition on the block and then each pipe of the header.

very unlikely directly a sensor or electrical as it should of errored that if drastic.

 

the maf meters on those things are very simple that can be checked by disconnecting it while its in the air box and see if anything changes afterwards, other than that is continuity check as they just check rough temp and pressure within.

 

might be something simple like a blocked, sticky, weak spring, loose bracket on the air flow intake valve.

there are quite a few others but until you can check those and narrow it down.

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Look for an air leak first, I'm not up on blackbird, if maf is resistance based could just be a build of of grime on wire, clean first, could be faulty maf giving incorrect reading on which it will base it's fuel mixture, does it have an air temp sensor or a lambda ?

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Thanks for info, very informative guys, the maf and air leaks seems be my first port of call. can't see any mention of a air temp sensor in the manual or a lambda (just a standard exhaust) 

I don't have a thermo gun hopefully won't need one, I'll let you know how things are working out. Thanks again for the for taking the time to post.

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11 minutes ago, Vic101 said:

Thanks for info, very informative guys, the maf and air leaks seems be my first port of call. can't see any mention of a air temp sensor in the manual or a lambda (just a standard exhaust) 

I don't have a thermo gun hopefully won't need one, I'll let you know how things are working out. Thanks again for the for taking the time to post.

Had a quick Google looks like it has a map rather than a maf whilst still a possibility more unlikely, still check for vacuum/air leak.

 

Has a wax valve that helps look after choke IE running rich when warm, if the fecks up it's running rich.

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Don't know anything about the Blackbird in particular but would look at;

Air filter

Water temp sensor, from what I can see online its on the thermostat housing next to the guage sender.

Does it get up to running temp ok, thermostat ok.

MAP sensor as you have already suggested.

Rubber piping around throttle bodies for perishing.

Fuel filter.

Fuel pressure.

Throttle balance 

Does it have an eml at all, can you run a diagnostic check?

 

What mpg are you getting, what sort of riding are you doing, town, long distance?

Is the bike ok mechanically,  tyre pressures, chain condition, brakes not dragging.

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1 hour ago, Bianco2564 said:

Does it have an eml at all, can you run a diagnostic check?

 

What mpg are you getting, what sort of riding are you doing, town, long distance?

Is the bike ok mechanically,  tyre pressures, chain condition, brakes not dragging.

 

Morning all, thanks for all the advice it's all great information. The bike is almost new its done 9k miles 42psi nothing is seized and it has its own diagnostic checking system that flashes, the F1 system is not flashing. The mpg is ridiculously low its using a full tank after 60/70 miles, I tend to avoid towns when ever possible it's not the type of bike you want to use in town.

 

12 hours ago, Bender said:

Has a wax valve that helps look after choke IE running rich when warm, if the fecks up it's running rich.

So this is something, the wax valve is like an automatic choke on a carburettor setup from what I see.  So it should be revving higher when you first start the bike from cold and should be lowering the revs has the bike warms up. That would be something I would have noticed and haven't.

This is something else I need to look into.

Thanks again for all your ideas I would be sat here scratching my head without it.

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Ok, so far the wax valve (choke) seems to be working as it should, the revs start at 20k and drop to 5/7k after about 5mins. Unless I'm missing something.

Off with the tank then, takes the seat off fully expecting two 12mm bolts, oh no! Torx bolts and have no Torx set, so I ordered a set and a thermo gun just in case.

I've been meaning a get a Torx set for a wile. not much I can do for a wile.

 

 

1 hour ago, Simon Davey said:

I'm following because I have a similar issue, but I have carbs.

The clue I have from this is my temperature gauge not rising, so I'll look into that first.

hope there is something here that can help, good luck.

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Very first thing I do with any petrol injection fault is to put a full bottle of this in the fuel and run it till the tank is nearly empty over a few days.  It is what the pros use.

 

s-l1600.png

 

 

 

 

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1 hour ago, Nick the wanderer said:

Hi,

did you manage to change the air filter? 

Hi, I need a Torx socket set so I can take the tank off, so I ordered one. I can't get to the air filter with the tank on.

 

Not sure if it is a injection fault just now, starting with air intake or the lack there of. 

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Most injections either work or dont work, wont let fuel past (so off by default) or will but either a normal fine spray or fob it out (particularly blocked jet). Now this might give the rich fuel as its not fine enough to burn quickly nor nice.

 

Good suggestion of the valve but generally its one of those does or not, the wax choke would be very noticeable by not running the choke at start up or would be running at high choke even when warmed up.

as it warms up the wax softens and closes the valve to the extra fuel.

 

SD how similar? Generally sounds like a simple temp gauge sensor, are you taking of water? Gauge if its just saying something, but if its over heating quickly  its the valve or if water in the oil its gasket.

Edited by RideWithStyles
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7 hours ago, RideWithStyles said:

 

SD how similar? Generally sounds like a simple temp gauge sensor, are you taking of water? Gauge if its just saying something, but if its over heating quickly  its the valve or if water in the oil its gasket.

At air temperature of 6 degrees, the water temperature gauge barely moves, unless I give it a good caning. 

I would still expect the gauge to rise under normal load though. 

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Posted (edited)
10 hours ago, RideWithStyles said:

Most injections either work or dont work, wont let fuel past (so off by default) or will but either a normal fine spray or fob it out (particularly blocked jet). Now this might give the rich fuel as its not fine enough to burn quickly nor nice.

So would this make the bike run badly? Because it flies like a bullet and never misses a beat.

Edited by Vic101
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Yes it can. Think of it like u drink a bottle at you own rate  every thing is fine but then someone squeezes the bottle to push more in bigger gobs like...what u think happens. Difference is it doesnt come back out of its mouth, its forced to the chamber but the bike thinks and expects its the smaller finer vapour so it uses that map as so but the bike coats up especially at start up or toddling in town work alot, its harder to map a engine at low revs and low load than at high revs with low or high load.

 

it still will go quickly as a 1100 with four cylinders pumping out 150 hp plus...this will be a gradual thing where you might not notice as its just your bike in isolation. just where you might notice mostly on roll on or off at low to mid revs. 
no harm in giving it a fuel tankfulls of fuel flush and use lower gears with higher revs than you do now to help it out if it's chocked.

 

SD if the valve was gone (default is closed) bikes over heat as general they stay closed to help heat the water up quickly then as it heats up gradually opens up to let the warm water flow out to get cooled before returning back to get heated up again. If its permanently open (very rare but depending on whay type or othrr parts it could be jammed opened so is always cooled. Does the bikes fan ever kicks in even if its in traffic or left to tick over?
Is that actually water or oil temp is it reading??? 

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19 minutes ago, RideWithStyles said:

SD Iif the valve was gone (default is closed) bikes over heat as general they stay closed to help heat the water up quickly then as it heats up gradually opens up to let the warm water flow out to get cooled before returning back to get heated up again. If its permanently open (very rare but depending on whay type or othrr parts it could be jammed opened so is always cooled. Does the bikes fan ever kicks in even if its in traffic or left to tick over?

Is that actually water or oil temp is it reading??? 

I think I need to ride the bike more. I've literally clicked my 3rd hour this morning. 

For the whole hour, the needle was right at the bottom, until I gave a few gears the 10k treatment 5 minutes before home, then whilst it was idling at home using what was left in the carb's (fuel turned off) I noticed the temperature was up a third. 

 

20240107_101938.JPG

 

It was only 1 degree, and it might be that I've only ridden it in temperature less than 5/6 degrees..... 

Edited by Simon Davey
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3 hours ago, Simon Davey said:

I think I need to ride the bike more. I've literally clicked my 3rd hour this morning. 

For the whole hour, the needle was right at the bottom, until I gave a few gears the 10k treatment 5 minutes before home, then whilst it was idling at home using what was left in the carb's (fuel turned off) I noticed the temperature was up a third. 

 

20240107_101938.JPG

 

It was only 1 degree, and it might be that I've only ridden it in temperature less than 5/6 degrees..... 

I think you are miss understanding the concept of a temperature gauge on a vehicle and that of a thermometer. I would say your bike is running ok.

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3 hours ago, Simon Davey said:

I think I need to ride the bike more. I've literally clicked my 3rd hour this morning. 

For the whole hour, the needle was right at the bottom, until I gave a few gears the 10k treatment 5 minutes before home, then whilst it was idling at home using what was left in the carb's (fuel turned off) I noticed the temperature was up a third. 

 

20240107_101938.JPG

 

It was only 1 degree, and it might be that I've only ridden it in temperature less than 5/6 degrees..... 

The thermostat should control the engine temp irrespective of ambient temp, that's its job. If you have an infrared pyrometer (£10 off ebay), run the engine up from cold and measure the temp at the thermostat housing, should see it rise to 80-85degC or so, stat should then open and start to cool the engine, temp will drop as flow begins. Will take a while to stabilise, then as eng temp increases until the rad fan kicks in, probably somewhere near 100C. All the while, watch what the bike temp guage is doing.

If the stat housing only reaches say 50C ,I'd say your thermostat is fubarred.

Got this on my car currently, doesn't have a temp guage but I noticed the heater wasn't great, checked it out yesterday and its only reaching 50C after 5 miles of driving.

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20 minutes ago, Bianco2564 said:

The thermostat should control the engine temp irrespective of ambient temp, that's its job. If you have an infrared pyrometer (£10 off ebay), run the engine up from cold and measure the temp at the thermostat housing, should see it rise to 80-85degC or so, stat should then open and start to cool the engine, temp will drop as flow begins. Will take a while to stabilise, then as eng temp increases until the rad fan kicks in, probably somewhere near 100C. All the while, watch what the bike temp guage is doing.

If the stat housing only reaches say 50C ,I'd say your thermostat is fubarred.

Got this on my car currently, doesn't have a temp guage but I noticed the heater wasn't great, checked it out yesterday and its only reaching 50C after 5 miles of driving.

That makes perfect sense, thank you.

Now, where's me owner's manual,,,,,,,

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11 minutes ago, RideWithStyles said:

Pretty sure its oil temp.

Must be water, surely?

The water jacket cooling the engine, will also mean the engine oil is also kept cooler?

 

Apologies for hijacking the thread @Vic101

Edited by Simon Davey
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😐.

depends on the engine.


The gauge doesn't mean water as default which im guessing your thinking?

if that was so oil would be run round the sump....the water is not needed to keep the oil cool. Water has a lower boiling point and Oil likes it hot,

 

 

Edited by RideWithStyles
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