engine judder at low revs

[manuel32]

When cruising around town,20-30 mph open the throttle and pulls then judders, like missfiring pulls more missfires a little bit the goes well, not noticable at higher speeds, shut the throttle at speed and open again its fine.


Its just 20 to 40 mph when opening the throttle a little or alot.


Battery is fully charged, fresh petrol in, shells best.


Anyone any ideas?

[tomlinscote]

I had a similar problem a while back ,it turned out to be a damp spark plug, I had washed the bike and not noticed one of the plug caps was not too tight. Once all dried out it was as normal.
 

[ghostbiker]

What gear?

[AdieR]

Any particular rev range?

If you take your spark plugs out, they'll tell you a story by their colour; FWIW, it might be worth trying a new set if you haven't already.

Is there a pattern to it (only when cold / hot / wet)?
Does it miss when revved on its stand, or only under load?

[manuel32]

warm engine, any gear, not under strain, just open the throttle and its misses a bit. enough to dip the front forks,noticable up to about 40mph.


does not miss a beat when going well , on the power.higher speed.

[Falcon 269]

On a Gen II, my first thought would be check the coils on each plug.  They're known to fail.

[manuel32]

The dealer said he would send a new set of plugs in the post,just have to find out which ones  now,, anyone know the correct plugs, 2007-8 fz1 plugs?

[AdieR]

From Halfords Website, 2006-on FZ-1 uses NGK plugs CR9EK, if that helps.

[manuel32]

I knew there would be help.thanks matey