First Post 1977 Kz 1000

I have a 1977 kz 1000 with 52,000 miles on it. I have no idea what needs to be replaced and what has had work done. The problem I’m running into right now is the bike won’t go over 6k rpms it hits a wall. I took the carbs off and cleaned them. It’s still doing it. I’ve looked for the adjustment screws but I only see one on each carb near the intake. Is there another one for fuel I don’t see or is it just one screw for both. Not sure never ever worked on carbs or have had anything with them. Thank you!

Welcome.

I believe there's some carb info in the filebase area on the forum here.
Look for a service manual downloads as well if you don't already have a manual.

Do post up some pictures of your KZ. 

Hey HamFam,

The screws near the head intake boots are pilot screw fuels.  They only control a little of the throttle position; basically idle to 1/8 throttle if that.  You’ll need to see what jets sizes are in the carbs. That should help us determine what’s going on. 

Later, Doug

Welcome aboard.

The problem could be a rusty ignition advancer. Might be a fuel delivery problem. Could be a rat's nest in the air filter box or exhaust system.
In addition to the pilot mixture screws, there are synchronizing screws that adjust the throttle valves to each other and an idle adjustment screw for setting the idle speed. It is highly unlikely that any of them are causing the problem.

I recommend doing all of the routine maintenance listed in the factory service manual and the owners manual.

Here is a copy of the factory service manual.   www.kzrider.com/filebase-alias?task=down...id=1159&catid=20&m=0

Sounds like a new acquisition? Because you said you don't know what has been done/replaced. More info Please/pictures! Does it have original Exhaust and Airbox? Open baffle/alternate exhaust will cause that 6K RPM limit. Those brass screws, fuel or air won't have any effect on your symptoms if it's not revving past 6K. If all else is OK, need to jump to a bigger main jet.  

Synopsis of above:
   Full evaluation of motor health.  Valve lash, static and dynamic spark timing (ignition advancer), spark energy, float height, hot compression #'s, clean air filter(s).
   Pods?
   Any mods to intake or exhaust systems?
   Does it not rev past 6K in 1st.?  Or in 5th.?  If the latter, final drive gearing?

   Visible carb adjustment screws only affect idle up to ~1/4 throttle.  Above that is needle jet & jet needle up to not quite WFO.  Full throttle is dependent on main jet, float height and, to a lesser extent, fuel flow (petcock & fuel filter) capabilities from tank to carbs.

   Recommend not going immediately to carbs until everything else is well-known and good.

Good Ridin'
slmjim & Z1BEBE
 

Yeah my distant father left it to me in his will and I really have zero idea what was done to it. I don’t actually have that many pictures of it put together haha 

I have cleaned the carbs,
New battery,
new plugs and wires, 
new cables, 
cleaned brakes up,
cleaned gas tank, 
 

Yes...you have the worst case scenario for stock carbs. Pods AND open 4-1 header. As everyone has mentioned, pull those carbs again and record the #'s on the Main and Pilot jets and report back. 

It looks like the top one says 07.5 and the bottom 2.5 

Those carbs are not stock, they are 29 Smoothbores. Note the little phillips screw on one side. The two sizes provided, 07.5 and 2.5. Probably look closer and there will be a one so 107.5 , need something like a 115-120 to begin with. The other 2.5 is the float seat, nothing needs to be altered on that. There's another jet in there too, the pilot jet. But if it starts/idles then you're ok. And don't remove that little phillips screw!! Sounds like you're not familiar with these and that little screw sets the slideblock.

Noteworthy!! Don't over-tighten the Jet Holder or also called the emulsion tube. Its the 8mm socket brass that is holding the 107.5 main jet. Strip-out the slide/Jet block and you're screwed!! Looks like this, lower one in picture. 

Yes not familiar at all haha, but I didn’t unscrew anything yet. The 6k rev limiter I feel I’m hitting happens in all the gears.  Bike starts right up idles well, it’s just that 6k wall I hit.