my fz6 seems restricted on power after it warms up

[newbie001]

I have been a pretty happy owner of 2005 fz6 until 6 months ago;
the bike was great till about 7000 miles -- lots of power , no buzz at highway speeds, no handlebar vibrations whatsoever;

for the last 2500 miles it is been very dissapointing; In fact I am on the edge of selling it;

It seems to ride fine while still relatively cold ( first 10-20 mins); after that, the bike seems like it is underpowered and restricted; also at highway speeds ( over 60mph) the engine sounds like it is doing a lot of extra work to the point that handle bars give me tingling ( it was not doing it before so I do not think it is common issue as some owners report they experienced from day 1 with their bikes);
I used to ride at speeds over 90mph for 20-30 mins continuosly on hwy280 at traffic pace and it used to be very smooth ( not anymore
);

So far I checked the TPS and the range goes from 16 to 97 in diag mode -- which is normal;
engine rpm is stable at any speed when I lock the throttle with my cruise control;
bike never stalled; always starts perfectly;
I pulled the spark plugs, no carbon deposits ( little dark but no carbon fouling);
I pulled the air filter, cleaned it ( it was not that bad in a first place anyway), checked all the hoses to the air box;
Fuel economy seems ok -- 35-40mpg;
I pulled out the air box, checked the throttle bodies for any sings, carbon deposits -- not seeing anything strange visually;

I ran the seafoam in the tank and sprayed some in the throttle bodies; it helped a little bit for some periods but did not fix the issue;

what I noticed, sometimes lately I have some extra exhaust smoke or smell , but it is very intermittent;
my pipes are stock, and they have some dark carbon deposits ( not really sure if it is normal over time for my 9500 miles or related to my problem);

should the inner pipes in the exhaust be dark or clean and shiny ?


next on my list would be to check the reed valves, pull out the throttle bodies and check deeper in the manifolds for any sings;
next will check the valve clearances -- but at 9500 miles I doubt it is the valves ( I never race it or aggressive with it, never ride over 6-7k rpm );

I used to put 91 octane fuel; lately been putting 89 to see if anything will change -- same problem;

I changed oil to spectra gold cap semi synthetic to see if engine will benefit last month -- no help;

can it be crankshaft position sensor? carbon build up in combustion chamber?

I can still rev it up to 7-8-9k rpm and go to 90-100mph, it is just running very restricted and totally different from before - no more smooth easy breathing;


hope someone can give ideas; ( or an experienced mechanic I can trust here in bay area who can ride it and feel what's going on -- experienced is the key word here since most dealer would just say it is normal, charge for diagnostics and suggest a bunch of unnecessary part replacements that will not address the issue ); one dealer told me to replace the tps, but it does not have idle or rpm issues or stalling ever, and in diag mode always goes gradually from 16 to 97;

also some owners report the issue with buzz and underpowered restricted in the 5000-7000rpm, then normal above that, but mine stays pretty restricted through the entire rpm range -- very uneasy breathing, no coughing or jerking, still smooth acceleration but uneasy and restricted.

so hope can get some inputs from you guys/gals; ( I used to love my bike
-- not anymore);

thanks

 

[RJ2112]

I'm wondering if you have a fuel delivery problem.

Normal op at idle, with issues higher in RPM seems to indicate something engine speed related. Acting congested either points to airflow, or fuel delivery.

As you have replaced the air filter, and the mileage on the bike is way less than 25K I can't think the valves are out of whack..... valves out of adustment generally lead to hard starting as well.

Your MPG seems quite low to me. Especially if you are as mild on the throttle as you seem to indicate. I'd be looking for near 50 MPG if the bike did not routinely see anything approaching red line, and spent a good part of it's time on the freeway at steady state speeds.

What is the condition of your drive line? Is there any rust in the chain? How do the sprockets look?

Do you have any luggage attached to the bike?

 

[Motogiro]

I have been a pretty happy owner of 2005 fz6 until 6 months ago;
the bike was great till about 7000 miles -- lots of power , no buzz at highway speeds, no handlebar vibrations whatsoever;

for the last 2500 miles it is been very dissapointing; In fact I am on the edge of selling it;

It seems to ride fine while still relatively cold ( first 10-20 mins); after that, the bike seems like it is underpowered and restricted; also at highway speeds ( over 60mph) the engine sounds like it is doing a lot of extra work to the point that handle bars give me tingling ( it was not doing it before so I do not think it is common issue as some owners report they experienced from day 1 with their bikes);
I used to ride at speeds over 90mph for 20-30 mins continuosly on hwy280 at traffic pace and it used to be very smooth ( not anymore
);

So far I checked the TPS and the range goes from 16 to 97 in diag mode -- which is normal;
engine rpm is stable at any speed when I lock the throttle with my cruise control;
bike never stalled; always starts perfectly;
I pulled the spark plugs, no carbon deposits ( little dark but no carbon fouling);
I pulled the air filter, cleaned it ( it was not that bad in a first place anyway), checked all the hoses to the air box;
Fuel economy seems ok -- 35-40mpg;
I pulled out the air box, checked the throttle bodies for any sings, carbon deposits -- not seeing anything strange visually;

I ran the seafoam in the tank and sprayed some in the throttle bodies; it helped a little bit for some periods but did not fix the issue;

what I noticed, sometimes lately I have some extra exhaust smoke or smell , but it is very intermittent;
my pipes are stock, and they have some dark carbon deposits ( not really sure if it is normal over time for my 9500 miles or related to my problem);

should the inner pipes in the exhaust be dark or clean and shiny ?


next on my list would be to check the reed valves, pull out the throttle bodies and check deeper in the manifolds for any sings;
next will check the valve clearances -- but at 9500 miles I doubt it is the valves ( I never race it or aggressive with it, never ride over 6-7k rpm );

I used to put 91 octane fuel; lately been putting 89 to see if anything will change -- same problem;

I changed oil to spectra gold cap semi synthetic to see if engine will benefit last month -- no help;

can it be crankshaft position sensor? carbon build up in combustion chamber?

I can still rev it up to 7-8-9k rpm and go to 90-100mph, it is just running very restricted and totally different from before - no more smooth easy breathing;


hope someone can give ideas; ( or an experienced mechanic I can trust here in bay area who can ride it and feel what's going on -- experienced is the key word here since most dealer would just say it is normal, charge for diagnostics and suggest a bunch of unnecessary part replacements that will not address the issue ); one dealer told me to replace the tps, but it does not have idle or rpm issues or stalling ever, and in diag mode always goes gradually from 16 to 97;

also some owners report the issue with buzz and underpowered restricted in the 5000-7000rpm, then normal above that, but mine stays pretty restricted through the entire rpm range -- very uneasy breathing, no coughing or jerking, still smooth acceleration but uneasy and restricted.

so hope can get some inputs from you guys/gals; ( I used to love my bike
-- not anymore);

thanks

Do you have a different sprocket?
You may have done this already. Try disconnecting your battery for a few minutes. Re-connect it and try it...
I've had my FZ6 do funny stuff and this corrected it.

 

[newbie001]

thanks for your fast reply;

chain is rust free and sprockets are good too; it is garaged;

yes fuel economy is low, not sure way, been like this since day 1;
I ride in city a lot too, though, but still keep the bike under 4-5k rpm in 3rd 4th gears mostly;

I have givi top case and ride solo 100%;



so as far as fuel delivery goes, should i remove the fuel filter and see the condition, then go to injectors ( remove the rails , etc.) and check them for any gum or dirt inside;

can I rule out the engine internals, pistons , rings, etc? ( again 9.5k miles and no abuse);
should I check engine cylinders' pressure?


thanks

 

[newbie001]

Do you have a different sprocket?
You may have done this already. Try disconnecting your battery for a few minutes. Re-connect it and try it...
I've had my FZ6 do funny stuff and this corrected it.

I have original sprocket, all stock actually, except the sound system and cruise control;

I think it is air/fuel related but I may be wrong of course;

I will try the battery disconnect to reset ECU, etc.
Plus I ordered carbtune from UK and will recheck the throttle body sync; ( the last time I checked with single gauge one -by-one and seemed ok , but wil do all 4 at the same time as soon as I get the manometer)

thanks

 

[champion221elite]

Do you have access to a dyno tester? Sometimes local cycle clubs or tuner shops will offer single dyno runs for a pretty reasonable charge.

This should help give you a good baseline number to see where you're at.

 

[newbie001]

does anyone know/have/trust an experienced mechanic in bay area who will test ride the bike ? ( I do not think I wanna take it to K&C engineering or dealer for that)

 

[newbie001]

Do you have access to a dyno tester? Sometimes local cycle clubs or tuner shops will offer single dyno runs for a pretty reasonable charge.

This should help give you a good baseline number to see where you're at.

I do not have the access to dyno; the thing is that it used to run normal and now it is ill;

what will dyno test show? (mapping problem?, fuel delivery issue?)

 

[champion221elite]

The dyno will show what your overall horsepower is.

A healthy motor will be around 90+ hp. Depending on how advanced the dyno machine is, there will also be sniffer inserted into your tailpipe. This will help determine if your air/fuel ratio is correct.

 

[Motogiro]

I do not have the access to dyno; the thing is that it used to run normal and now it is ill;

what will dyno test show? (mapping problem?, fuel delivery issue?)

Usually a dyno is used to tune the bike and usually using an aftermarket computer but sticking a sniffer in the tail pipe with a run on the dyno might show what's going on and you could go from there. At least you'd get a reference on Air/Fuel mix etc.

Edit: Haha! Champion bet me to it!

 

[RJ2112]

thanks for your fast reply;

chain is rust free and sprockets are good too; it is garaged;

yes fuel economy is low, not sure way, been like this since day 1;
I ride in city a lot too, though, but still keep the bike under 4-5k rpm in 3rd 4th gears mostly;

I have givi top case and ride solo 100%;



so as far as fuel delivery goes, should i remove the fuel filter and see the condition, then go to injectors ( remove the rails , etc.) and check them for any gum or dirt inside;

can I rule out the engine internals, pistons , rings, etc? ( again 9.5k miles and no abuse);
should I check engine cylinders' pressure?


thanks

As far as internal issues..... if your oil is clean (no debris, and no massive engine smoking) it's most likely okay. A compression check is the ideal way to find out the health of the internals of the engine. That will check the sealing between the piston rings and cylinder wall, as well as the valve seal with their seats.

If you have always operated the bike @ less than 7K, it may just have gotten 'loaded up' over time. This thing doesn't really wake up until you have at least 5K on the tach; and performs best between 7 and 10K. If you visit that region on a regular basis you are operating the engine as designed.

The fuel filter is attached to the fuel pump, which is submerged in the fuel tank. I would start out by shining a flash light in the tank, to look for sludge and varnish. An '05 with less than 10K miles almost certainly has to have sat idle for some months at some point.... the volatile parts of the fuel will evaporate out, and leave the 'heavier' elements behind..... leave it long enough, and you get the La Brea tar pits inside your fuel system. Not good. This is especially true with the 10% alcohol fuels..... that stuff goes 'off' fairly quickly.

It's tough to look in there.... no direct lines of sight. A small mirror may help.

If it's already gummy, blocking the screen, it would tend to deliver a limited amount of fuel.... which would become noticeable with more RPM. The engine would starve for fuel.

I'd try some fuel injector cleaner, at the highest recommended strength to see if it can dissolve the gunk I suspect is causing the problem. Next step would be to pull the pump from the tank and inspect it more closely.

 

[newbie001]

thanks, I wil try to see who does it in the bay area for reasonable amount since performancewise I was fine without any PC3 or remapping before this current issue. ( I use bike as a primary transportation lately and do not care about too much power, just want it to breath naturally)

 

[newbie001]

As far as internal issues..... if your oil is clean (no debris, and no massive engine smoking) it's most likely okay. A compression check is the ideal way to find out the health of the internals of the engine. That will check the sealing between the piston rings and cylinder wall, as well as the valve seal with their seats.

If you have always operated the bike @ less than 7K, it may just have gotten 'loaded up' over time. This thing doesn't really wake up until you have at least 5K on the tach; and performs best between 7 and 10K. If you visit that region on a regular basis you are operating the engine as designed.

The fuel filter is attached to the fuel pump, which is submerged in the fuel tank. I would start out by shining a flash light in the tank, to look for sludge and varnish. An '05 with less than 10K miles almost certainly has to have sat idle for some months at some point.... the volatile parts of the fuel will evaporate out, and leave the 'heavier' elements behind..... leave it long enough, and you get the La Brea tar pits inside your fuel system. Not good. This is especially true with the 10% alcohol fuels..... that stuff goes 'off' fairly quickly.

It's tough to look in there.... no direct lines of sight. A small mirror may help.

If it's already gummy, blocking the screen, it would tend to deliver a limited amount of fuel.... which would become noticeable with more RPM. The engine would starve for fuel.

I'd try some fuel injector cleaner, at the highest recommended strength to see if it can dissolve the gunk I suspect is causing the problem. Next step would be to pull the pump from the tank and inspect it more closely.

well, I ride it year round, at least 1-2 times a week, even in rain;

I used seafoam to let it clean the fuel system, and I wil use it again this weekend to see if any even slight change;
then of course will check and examine the fuel tank , pump, fuel filter( got Haynes manual -- best investment to learn and take apart things );

will put new plugs even though old still seem ok;

Now I wish it stalled or coughed or something to give me some clue, but it does not do any of that; (and seeing so many riders put over 30-50K miles on these bikes without even valve adjustment needed makes me wonder.

 

[newbie001]

thanks again and by the way , what do u mean system got loaded up if ridden under 7k rpm? is it bad to ride it mildly?( under 6-7k rpm)

 

[champion221elite]

thanks again and by the way , what do u mean system got loaded up if ridden under 7k rpm? is it bad to ride it mildly?( under 6-7k rpm)

Inline 4 cylinder engines are meant to be run at higher RPM's. Think of it this way... you have an engine that was designed to run up to 14,000 rpms, but instead you're running it 5,000 to 6,000 rpms. At the lower engine speeds, you're bound to have fuel residue stay inside the motor instead of being purged out the exhaust system.

As the miles add up, this build-up can increase and choke out the system. Nobody is saying you need to redline your engine at every shift, but exploring it's upper reaches certainly could do your bike some good.

 

[ecudoc]

If it's already gummy, blocking the screen, it would tend to deliver a limited amount of fuel.... which would become noticeable with more RPM. The engine would starve for fuel.

I'd try some fuel injector cleaner, at the highest recommended strength to see if it can dissolve the gunk I suspect is causing the problem. Next step would be to pull the pump from the tank and inspect it more closely.

I'm no expert at any rate, in fact I am far from an expert, but if it were a fuel delivery problem of any sort, would the plugs not show? Or is there a way for it to run without the correct air-fuel and not show signs relating to the symptoms. ?

 

[RJ2112]

I'm no expert at any rate, in fact I am far from an expert, but if it were a fuel delivery problem of any sort, would the plugs not show? Or is there a way for it to run without the correct air-fuel and not show signs relating to the symptoms. ?

The plugs will show a situation where there is too much fuel...... not a good indicator of too little. Especially if the 'too little' is not consistent.

If the injectors are applying the impulse to squirt in the right amount of fuel... the motor will run with the correct fuel/air ratio..... the pressurized fuel rail is the source of fuel; but if it's limited in how much it can provide, it can still do so at the correct pressure.... but not at larger volumes than what would be needed at or near idle.

To maintain the correct ratio, the injectors have to squirt long enough per intake stroke to meet the need... the higher in RPM you go, the longer the pulse -- that, and how hard you have the throttle twisted. If the 'pipe' is too small, it'll run right in low demand scenarios, and then not be able to 'keep up' when the demand increases. Full throttle at max RPM demands a LOT more fuel than idle/near idle lightly loaded..... The injector may cycle for long enough, but if the fuel is not there, there won't be a power increase.

Same sort of thing as running really small jets in a carb.

 

[ecudoc]

Oh, Well that helped me out lol, good point!! :thumbup:

 

[Ridgerunner1061]

Aloha-
Have you tried the basics like check tire pressure and brake movement. Some tires are hard and roll easy until they are warmed up. Once they are warm they become more flexible and offer a lot of drag if not properly inflated.

Same holds true for your brake calipers. If they start sticking after you have been ridding for awhile they will create access drag as well.

Good Luck.

 

[RJ2112]

thanks again and by the way , what do u mean system got loaded up if ridden under 7k rpm? is it bad to ride it mildly?( under 6-7k rpm)

newbie,

another point I finally noticed in your first description... the bike seems to run properly for the first few minutes, then starts running like it's running out of air?

That may indicate an issue with the ECU not selecting the appropriate 'map'.... if it never comes off the 'cold/default' map, it's eventually going to start running too rich, like you've left the 'choke' on. That would lead to the same sort of drop in performance you are observing, I think.

Perhaps the engine temp sensor is faulty?