TOPIC:

Hi guys.

Is there anyone who knows why my KZ750 B1 doesn´t want to take more than 4000 rpm with my pod filters on??

I have increased the mainjet by making the hole bigger. I have also lifted the neddle up two steps.

The idling and throttle all the way up to 4000 rpm is strong and fast (runs well), but it jumps and stays at 4000rpm and it wont take any further rpm.

Do you guys know the problem??

Hope you can helpme!

Kind regards Andreas

Check and see if they are blocking the large vents at the top of the carb mouth. They have to be clear and it's a common problem with some pods.
Steve

If it was mine I would toss the pods in the trash can, buy new stock jets, assemble and ride.

BUT since it is unlikely you will do that I suggest the first thing you do is toss the jets you made bigger holes in (what did you use to determine the exact size hole needed, and how did you enlarge the holes with precision?).

If you are bound and determined to use pods (I can't guess why) I suggest you buy a jet kit and start from there. That should give you at least a fighting chance of getting the bike to run halfway decent with pods.

I hope you understand you are fighting an uphill battle trying to get CV carbs with pods to work as well as the stock setup. Ed

I missed that. You made the jets bigger, then raised the needle? You're drowning it. Ed's right. Unless you know what you are doing and have the time, patience and money, get stock jets, put the air box back on and hope you didn't mung it up too bad.
Steve

See the short video below showing how the CV carb operates. It may help you understand why getting CV carbs to work well with pods is difficult.

Notice in time 0:09 - 0:16 that the diaphragm, throttle slide, and jet needle hitched together and are controlled by the diaphragm, so the action of the diaphragm is of paramount importance to how the carb operates.

Now notice at time 1:21 that when the butterfly opens it exposes the throttle vacuum passage to the vacuum on the engine side of the butterfly. That vacuum then lifts the diaphragm which in turn lifts the throttle slide and the jet needle.

If the level of vacuum in the throttle vacuum passage is reduced because the use of pods increased the ease of air flow through the carb throat, the diaphragm will not operate in the same manner that it would have if the vacuum in the throttle vacuum was not reduced. If that happens, the slide and needle won’t be lifted at the same rate or to the same level.

Notice at time 2:03 when the throttle grip is twisted wide open and the butterfly is wide open there is very much air being drawn through the carb throat, yet there is still enough vacuum in the throttle vacuum passage to lift the diaphragm at a specific rate. That may not be the case if the resistance to air flow through the air filter is reduced or eliminated. Ed

Hmm bad news,

I have just re-installed the old/original airfilter box and now it won´t start! Can the pod filters damage something inside the carbs or?

All the starter cranking drained my battery, so I need to charge it again, before I can give it another try starting it.

You still have to bring it back to stock. Needles, jets etc.
Steve