Engine misses at constant speed

[NSNinja]

Hi,

I have a 1986 Kawasaki Ninja 1000 (ZX10). The bike is completely stock with the exception of the K&N Filter I installed last year.

When I got my bike out of winter storage and did the normal maintenance, it was running fine. A few weeks later I was out for a ride and the bike felt like it was missing while at a constant speed. If I twisted the right hand, it took right off as per normal. I did have troubles pulling away from a stop.

My assumption was that I am dropping a cylinder.

Here's what I've done so far:

checked plug wire connections (new wires last year and 1 new plug boot)
checked plug wires for damage
changed plugs
cleaned air filter
sync'd carbs (actually in the process of doing this now)


While at idle and not under load, all 4 cylinders are hitting just fine.

How do I trouble shoot problem? Right now I'm just doing lots of general maintenance hoping that I'll fix the problem.

Any tips would definitely be appreciated.

Thanks

NSNinja

 

[evelrod]

Good morning NSNinja---


Check your ign. switch and kill button for loose connections.
Check all your electrical connections and coil and ICU mountings.(Make sure any grounding straps are connected)
Check ign. timing.
You might check your new HT wires with an ohm meter just to make sure they haven't been damaged.(While you at it, check the windings on your coils, the specs will be in your service manual.)
Make sure the air box is installed correctly as it affects the airflow into the carbs.
Check plugs for correct heat range and type(I think I used NGK B-8EV but my K was an earlier model)
If you have a fuel filter, ck that.
Check fuel flow from your tank (contaminated fuel in your tank can cause all sorts of problems).
Check your fuel valves, main and reserve for blockage.
Check your carb float levels while your at it.
Check for air leakes around your intake manifold area.
Check your valve lash (A bike this old will probably be a little off)A DOHC valve lash might best be left to your dealer or an experienced tech.

One other thing , you may have to clean your carbs as storing a bike over the winter with fuel still in it can cause deposits etc. Adding a fuel stabilizer will help next winter.

The problem with this sort of miss is the probability of it being caused by more than one thing. Keep at it, if it ran ok before, it will run ok again.

This is a short list of probables, there are a lot of other things that could be wrong, but I suspect that it will be in your fuel system.


Rod

 

[sbc]

evelrod is right. ck your coils w/ a meter & visualy
at nite in a dark spot & try spraying them with a penitrating oil safe for this. also ck the grounds to the
engine maybe try a different brand of plug. I got a whole
box of nkg plugs that would short @ low voltage

 

[NSNinja]

Thanks for all your input. After testing a lot of different things it finally boiled down to the K&N Filter.

Appearantly I was not allowing it to dry complete before oiling, turning the filter into a gag.

I replaced it with the OE filter and was so pleased to have the problem solved, I did not go back to the K&N. I know that it must be a problem with the I'm cleaning the filter as it worked great when installed new.

Thanks again for all your input.