Kayo T4 sudden big out at 7k Rpms

[Jackstr]

So I just modified my Kayo T4, from a nibbi pe28 to a clone kehin pz30. Same jets as before (42/125). Runs good up at 6500, then sudden big out. I used to just knock on the door of 70mph redlining around 9k RPMs in 6th gear. No, I have to keep it under 7k, and that only gets me up at 45mph.

What's doing this?

[Megadan]

PE28 to a PZ30? That's a tad backwards in terms of performance, but I can tell you the solution is rather simple. Assuming you just dont have the choke on by accident (worth checking as it's happened to people before) The PE28 requires about a size bigger on the main jet when compare to a PZ30. The cutting out at WOT at higher RPM you are experience happens when you are very rich on the main jet. Take out that 125 and try a 120. Should see an improvement.

[Jackstr]

PE28 to a PZ30? That's a tad backwards in terms of performance, but I can tell you the solution is rather simple. Assuming you just dont have the choke on by accident (worth checking as it's happened to people before) The PE28 requires about a size bigger on the main jet when compare to a PZ30. The cutting out at WOT at higher RPM you are experience happens when you are very rich on the main jet. Take out that 125 and try a 120. Should see an improvement.

My purpose for the pz30 was to add the pumper so i could reduce off idle bog when accelerating. the pe28 did not have a pump, but the pz30 does. what sort of loss of performance do you mean? If i should go with a different carb, or go back to the pe28, i would like to know that.

p.s., i know the choke is not on, because it is a cable choke mounted on the handlebar, partly why i went to the pz30, and i could observe that it was off.

meantime, i will try leaning it out. I appreciate the insights.