[Tim Pappas]

If you can ease off the throttle and it pulls hard to 14k it’s jetting. Probably rich, but hard to say without knowing the details and looking at the piston.

[Glen Luening]

Thanks Tim will look into that but I have tried jetting with two different carbs. Do you think it could be ignition possibly?

[Tim Pappas]

Ignition is rpm sensitive, not throttle position sensitive, so if you ease off the throttle and it revs to 14k it’s not ignition. Check the reeds, proper fuel supply and if those are good, work on the jetting. KZ’s can be picky about proper jetting and it is not unlikely that you could try two carbs and jetting that don’t work with your engine.

[Bernie Baldus]

Sounds like it is too rich.

When you ease off the throttle, you are sticking the needle back into the nozzle and decreasing fuel flow.

Try a bigger needle, lower the needle, smaller main jet.  You are close, not way off, just a little rich.

What needle, nozzle etc.. are you running?

[Glen Luening]

I am going to pull the carb apart today and get that info. I will pst it as soon as I know. Thanks guys

[Matt Dixon]

I have been watching this thread because I thought it was lean.
Mr Pappas has forgot more about kart then I ever knew but this is why I was thinking that. By backing off the throttle a little arent you closing the slide? By closing the slide arent you reducing the air so in a sense “Fattening it up”? As for Bernie’s comment, isnt the needle only in the jet at the beginning of the throttle?

Sorry Glen I do not mean to confuse you and I am curious to hear what it was.

[Glen Luening]

Well this is what I have in the carb.

Atomizer is a DQ266

main jet 172

Needle is a k98 with the clip on the top groove

Idle jet is a 60 and the other one in the bottom of carb is a 50.

The slide is a 50.D7

I was reading Tom Barth’s posting in another thread and he says that a K21 needle and a DQ264 atomizer with a 144 jet is good for a KZ engine? Any thoughts on jetting would be appreciated.

No problem Matt, I am confused myself this problem has been going on for over a year now. And I believe if I am correct that backing off the throttle you are putting the needle back into the atomizer or nozzle there fore reducing the amount of fuel and making it leaner.

[Glenn L Riggs]

Well from your set up info I believe you are lean. I am in the midwest and you could have a completely different weather set up. But the k98 needle is a very large needle limits fuel some use as a qualifying set up. Don`t know what you have to tune with  but if you want to keep that needle you need to go to at least a dq268 tube or you could leave the tube and change the needle a k21 or k22 should put you close. Toms set up with a cq1 idle circuit 60 outer dq264 k93 needle works well am not always sold on the 130 main jet tho would start with a135 main this set up flows alot of fuel because of the small needle so to get peek power you got to be real close on the main jet. These are the set ups I use on a tm a pavesi seems to like less fuel so this should be a good starting point. Good luck

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