zx400 misfire and stutter at 4000K

[quaidpinder]

My zx is missing and stuttering at 4000K , have just given it a service ,plugs oil filter, fuel filter etc and it is stuttering and holding back and missing when being riden but on the stand and not under load there is no evidence of this at all , i was thinking that the carbs may be gunked up ? Does anyone no where there is a guide to stripping down a carb ?? I know the bike has been stood for a long time in the previous owners garage so it probably needs attention , any suggestions anyone ??

[zimm]

in brief, carbs are easy, just take 'em apart, clean everything and put them back together the same as they were.

the zxr H manual (main site) will give you the procedure settings, float heights and some pics.

it "could" just be one of the HT leads arcing to the cam cover instead of firing the plug.. used to happen a lot on ours as the cover isnt painted, and the leads/caps are 20 years old. I painted the cover, smeared some silicon sealant around the plug cap, and its been fine.

also, make sure you've got the carb to airbox rubbers seated correctly, they are a toad design, and can cause all manner of flatspots if kinked up.

[Mori Man]

Misfire certainly indicates electrical, i noticed that No.3 lead on my bike was leaking so will be replacing all with some nice Blue NGK stuff

Hesitant or stutters are more likely carb's being fouled, flat spot's are fuelling issues and requires jetting ect...

With you disturbing the HT leads to exchange plugs look around that area - don't rule out a "duff" plug either ! I pulled my hair out for two days trying to get the bike to start to discover the new plugs I put in were not doing it , another new set in and all was cured if you've got your old plug's still and the bike was running fine with them shove them back in and see what happens.

ATB