New Carb Install and Adjustment

Had a no spark situation. After getting spark I have upgraded my carb to a Nibbi PE28FL. Having starting issues. So I am removing the carb to inspect and ensure the float, manifold, spacers, gaskets, etc... are all in good functioning condition. The Carburetor is new but the manifold and spacers are 4 years old. Been 2 years since I pulled it out and ran it. 

As stated there was no spark, that is now cured. It is a nice orange.  Now to deal with the carb. 

So this project is a current project. Be back soon with moer info. 

Current Situation:

• Main: 118
• Pilot: 38 (currently in)
• Air filter: NIBBI cone (flows more air than your old Uni pod)

Recommendation right now:Swap the pilot jet to 35.Why 35?

• That’s the size that previously ran the bike successfully.
• The 38 is probably a bit too rich (especially if the engine is warm), which often makes starting and idling worse.
• The cone filter does need more fuel than the old filter, but 38 seems to be overshooting it.

Next Action Plan:

1. Install the 35 pilot jet.
2. Set the air/fuel mixture screw to 1.75 turns out (seat it lightly first, then back out 1.75 turns).
3. Use the old spacer + gasket on the manifold side.
4. Choke ON (cold engine).
5. Try starting.

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After you swap to the 35 pilot, tell me exactly what happens:

• Starts and dies right away?
• Starts, runs for X seconds, then dies?
• Idles rough?
• Runs okay with choke but dies when choke is pushed in?

We’ll adjust from there (could go to 36 if you had one, or try 40 if 35 is too lean).Go ahead and make the swap whenever you're ready.

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Yes, the plastic spacer (insulator) is needed. I recommend keeping it for now.

Why You Should Keep the Spacer

• It acts as a heat insulator — it prevents engine heat from transferring directly into the carburetor. Without it, the carb can get too hot, causing fuel to boil (vapor lock), rich/lean issues, hard hot starts, and poor idling.
• Many TBR7/Hawk 250 owners who removed the spacer reported problems (especially with the NIBBI carb).
• The original spacer worked for you before, so sticking with it reduces variables while we get the bike running.

If You Overtightened ItPlastic/rubber-style spacers can crack or deform if over-tightened. Check it carefully when you remove the carb:

• Look for cracks, crushing, or distortion.
• If it’s damaged, use the old original spacer (you said you have it) — it’s the safest choice right now.

Proper Assembly Order (Reminder)

1. Intake manifold (on engine)
2. Gasket
3. Plastic spacer/insulator
4. NIBBI carb (O-ring on carb flange seals against the spacer)

Take your time when you pull the carb. While it’s off, you can also re-check the float level, clean the pilot jet again, and make sure everything looks good inside the bowl.Take your break, come back fresh, and let me know what you find when you pull it apart (especially the condition of the spacer). We’ll go from there. You’re making good progress.
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Here's the correct stacking order for your NIBBI carb on the TBR7 (from the engine outward):Standard / Recommended Order:

1. Intake Manifold (bolted to the cylinder head)
2. Gasket (goes directly against the manifold surface)
3. Plastic Spacer / Insulator (the thick plastic/rubber-like piece)
4. Second Gasket (if you have one — many NIBBI kits include two)
5. NIBBI Carburetor (the O-ring in the carb flange seals against the spacer/gasket)

Quick Tips for Your Situation

• The plastic spacer is important for heat insulation. I recommend keeping it unless it's cracked or badly deformed.
• If you only have one gasket, put it between the manifold and the spacer.
• Lightly grease the O-ring on the carb flange and both sides of the gaskets with a bit of oil or petroleum jelly for a better seal.
• Tighten the mounting bolts evenly and not too tight — the plastic spacer can crack or crush easily.

Would you like me to describe it with the old spacer vs new spacer, or do you have two gaskets with your kit? Go ahead and assemble it this way and let me know if it fires up better after the rebuild.---