QFT 680 Questions

[alsant]

I have a QFT 680 and I need to rejet for higher altitude , do I replace both main jets and secondary jets ? I think I need to go about 3 lower than stock, but not sure about main and secondary.

Thanks

 

[GTX JOHN]

I would do all four jets at once. Three steps minimum would be the least I
would try first. Then look at plugs and maybe go a couple more numbers.

As I recall Prescott is about 5000 ft from what I remember, I delivered a trailer
to a Formula 5000 racer that we built for him there.