Motorcycle Repair: Dynojet stage 1,4 with Kerker exhaust on YX600

Question
Hello William

Yx600 Radian 1986, with dynojet stage 1,3 and Kerker exhaust, and aftermarket pods.

I previously had Dynojet 128, main jets at 3rd ring, and was getting lean symptoms:

1. needed full choke to start
2. As bike heated up had to reduce airflow/idle to correct for idling at 2500-3500 on deceleration.
3. Bike was popping/backfiring flames at end of exhaust.
4. tried tape on pods, did not help.

So:

Have moved dynojet needles to grove #4.

Now:

1. do not need choke (75 degres F)
2. No popping back firing
3. Bike idles at 1500 from cold to hot
4. Still have tape on pods.
5. set air/fuel mixture down to 3 turns.

Q1: Wondering if stage 1,3 recommendation for the bike should not be qualified with a possible 1,4 recommendation if running lean

Q2: are the DJ128 main jets the best bet or should i consider 124, or higher than 128.
The bike has smooth acceleration, previously surged at 3000 when main jets kicked in.

Thanks for your Help in advance

Agha

Answer
First Off. backfiring and flames is a Valve or Timing Issue.
Popping is a sign of a Lean Fule to Air ratio.
I would keep the #128 Main jets and Lower the E-Clip on the jet Needles to raise
the jet Needle a bit to give a richer fuel to Air ratio when throttle is applied.
There is a Tool that Helps with this Fuel to Air Ratio.
Gunson Colortune Tool..
You can leave the Main jets along and just move the E-clips on the jet needles.
The mixture screws are a fine tuning adjustment.
If you cant get Rich or lean enough with nthe mixture screws.
Then its time to change the range by moving the E-clips and then adjust the mixture screws again, while in a different range..
E-clip down a notch raises the jet needle and gives a Richer Fuel Mixture when the Main jets kicks in, 1500 to 2500 RPM's.
The Pilot jet is Fine if its Ideling Well.
Also check the plugs for color to see if the mixture is Rich (Black Plug)
or Lean (Gray or White Plug).