Yamaha Fz Misfiring

Grid · January 13, 2014

My Yamaha Fz is Misfiring when i accelerate at low revs... if i keep the revs above 3000 it doesn't misfire but somtimes when slowing don on 3rd gear it misses about twice.. also the engines is louder and has more thumping sound like a 250 d tracker but thisbike was never modified... acceleration is good but top speed is only about 75 - 80 kmph.. fuel economy also has dropped about 40 km per litre before it did about 55

ps. The bike was kept without use for about 6 months \ bike has ridden 22150 KM

MV-5 · January 13, 2014

spark plug?

Edited January 13, 2014 by MV-5

Hoonigan · January 13, 2014

To clarify, this is the FZ16 with the single cylinder engine right? And is it a carbie or EFI?

Checking the fuel lines for blocks would be a good start I think.

Grid · January 13, 2014

i replaced the spark plug but no use... also all the fuel line were flushed i even cleaned the air filter... this is the single cylinder carb model... do you think th carb is blocked or something?

Watchman · January 13, 2014

There was this thread on elakiri written buy a FZ16 owner. Fella knew that bike wheel-to-wheel. I came across it when someone shared the thread here on the AL forum. I tried looking for it here, but failed. You might want to look it up. It was really nicely written and will be very useful as a FZ16 owner

Edited January 13, 2014 by Watchman

MV-5 · January 13, 2014

On 1/13/2014 at 12:32 PM, Grid said:
i replaced the spark plug but no use... also all the fuel line were flushed i even cleaned the air filter... this is the single cylinder carb model... do you think th carb is blocked or something?

Next -> Ignition coil assembly (power coil).

don't buy, if you have a friend who has a same model, then you can give a "trial and error" attempt.

Edited January 13, 2014 by MV-5

Grid · January 13, 2014

On 1/13/2014 at 2:33 PM, MV-5 said:
Next -> Ignition coil assembly (power coil).
don't buy, if you have a friend who has a same model, then you can give a "trial and error" attempt.

Thanks .. i will try it... i really don't want to clean my carb cuz it cost a lot at A M W (for the 6000km service they charged 14500/=)

and a normal garage would screw it up ( happened to a friend of mine)

On 1/13/2014 at 1:02 PM, Watchman said:
There was this thread on elakiri written buy a FZ16 owner. Fella knew that bike wheel-to-wheel. I came across it when someone shared the thread here on the AL forum. I tried looking for it here, but failed. You might want to look it up. It was really nicely written and will be very useful as a FZ16 owner

I read it but there was nothing related to my problem..thnx anyway

Edited January 13, 2014 by Grid

Hoonigan · January 14, 2014

14500 for the whole service right? Or was that for cleaning the carb only? Which is crazy.

Single carb set ups aren't that hard to tune as far as I have heard and any mechanic worth his salt should be able to sort you out. Where do you live? If you are close to where I live, I can give you the contact of the guy who did both my bikes and he's awesome with carbs.

Grid · January 15, 2014

On 1/14/2014 at 5:14 AM, Hoonigan said:
14500 for the whole service right? Or was that for cleaning the carb only? Which is crazy.
Single carb set ups aren't that hard to tune as far as I have heard and any mechanic worth his salt should be able to sort you out. Where do you live? If you are close to where I live, I can give you the contact of the guy who did both my bikes and he's awesome with carbs.

for the service which only included an oil change(engine) and flushing the carb and fuel lines... I live in Athrurugiriya ...

Anyways I think i solved the problem for a while, i tightened the air/mix screw in the carb a little and the engine bacame a bit smoother, the thumping sound also stopped, there wasn't any misfiring through out the whole day but when i took it out at night it kept misfiring here and there at low revs...

Do you think it has something to do with the low jet ? cuz the misfire is only at low RPM abot 1000 - 2500

Hoonigan · January 15, 2014

On 1/15/2014 at 8:53 AM, Grid said:
for the service which only included an oil change(engine) and flushing the carb and fuel lines... I live in Athrurugiriya ...
Anyways I think i solved the problem for a while, i tightened the air/mix screw in the carb a little and the engine bacame a bit smoother, the thumping sound also stopped, there wasn't any misfiring through out the whole day but when i took it out at night it kept misfiring here and there at low revs...

Do you think it has something to do with the low jet ? cuz the misfire is only at low RPM abot 1000 - 2500

So it was running rich. Athurugiriya is not exactly close so my guy will be of no use for you.

I vaguely remember having a similar issue with the Bandit. But it was while cruising at low revs and a sudden throttle, which happened to flood the carbs. I don't remember exactly but it was either a small piece of dirt lodged in one of the jets or a stuck needle in one of the carbs.

But I'm sure a decent mechanic can get the carb cleaned and tuned. Like I said, the neighborhood makabass will surely screw up a four carb set up like in a CBR or something but a single carb single cylinder as yours is a fairly simple thing to fix. It could be a blocked jet as you say or simply out of tune. Best thing is to take it to a decent garage. If I'm not mistaken, there are a lot more Bajaj authorised garages than Yamaha ones around right? they should be able to help you as well.

Grid · January 15, 2014

On 1/15/2014 at 4:27 PM, Hoonigan said:
So it was running rich. Athurugiriya is not exactly close so my guy will be of no use for you.
I vaguely remember having a similar issue with the Bandit. But it was while cruising at low revs and a sudden throttle, which happened to flood the carbs. I don't remember exactly but it was either a small piece of dirt lodged in one of the jets or a stuck needle in one of the carbs.

But I'm sure a decent mechanic can get the carb cleaned and tuned. Like I said, the neighborhood makabass will surely screw up a four carb set up like in a CBR or something but a single carb single cylinder as yours is a fairly simple thing to fix. It could be a blocked jet as you say or simply out of tune. Best thing is to take it to a decent garage. If I'm not mistaken, there are a lot more Bajaj authorised garages than Yamaha ones around right? they should be able to help you as well.

thanks for your help... there's a bajaj repair centre close by, i will take it there and see if they can get the job done..