NEED HELP 81 kz1000j power loss at high rpms

I have an 81 kz1000 j model. It runs great untill i roll into higher rpms. Its smooth till the last quater throttle and it's just coughing and spitting. I think it's a fuel issue. Any help would be greatly appreciated.

If you are going lean at high rpms your spark plugs should have a brownish powdery look to the tips.. If they are dark you may well have a spark issue. Coils could be weak or bad and can't recharge fast enough to have a full charge at high rpm. Any of the circuitry in the coil wiring could have a marginal connection (for many reasons, oxidation, loose connection, etc) I'd run it again, create the missing condition and then pull the plugs right away. If they aren't brownish powdery, check the voltage at your coils. You should see north of 12v.

For reference: www.tuningmatters.com/how-tos/beginners-...-carburetor-setting/

Thank you I'll check it Sunday morning. I'm running the stock tdi and 3ohm dyna coils. Of that makes any difference.

That is a very good setup. (Dyna and tdi) Providing the proper voltage is reaching the coils. Your problem may well be fuel. You have to determine if it is fuel or fire (spark) and then chase it down which is why I lined out the two steps to try to determine which issue to run down.

Does the bike have the stock air box and filter and stock carb jetting? Ed

Check the fuel flow through the petcock and float bowl high.
A clogged filter or fuel line filter cause a low fuel flow and lean the mixture on high rpms.




Michael

Thank you I'm gonna pull the carbs Sunday the rear brake pump went out spent all weekend trying to get it working again. I had brownish plugs all dry. I'm running a V&h 4 into 1 and pod filters the frame has been modified too much for it to for now. What is the stock jet size? And anyone got any idea where i should be with those mods? The guy that owned it before me didn't really take care of it out a bunch of parts on and let it sit.

Service manual says pilots are 37.5 and mains are 127.5 for J models.

This is gonna sound ignorant but is the 127.5 the stock size or the size I should be at?

127.5s are the stock setup for model J's

I found that the pilot jets were blocked off by a plug is that a normal thing? It wasn't glued or anything just pushed in it looked legit made for the hole spot but I don't see why you'd block off your pilot jets.

Normal and necessary.

www.partzilla.com/catalog/kawasaki/motor...r-parts-kz1000-j1-j2