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I have a Speedster replica that came with a 2100cc motor dual Empi 44 HPMX, car barely starts, the main problem was the fuel system, the tank was rusted and full of trash, they had used some sort of coating that was coming loose, the carbs were full of trash, I rebuilt the carbs and this is how they had it set up,

Main jet 130  Air  200 E-tubes F11 Idle 65 Chokes (Venturies) 30mm main 55             acc pump jet 50

the engine has 160 compression in all cylinders and less than 6% leak down.

Any advice on the jetting, I"ve been out of the game since the 80s and only worked with Webers ( this looks like a replica of a weber 44  any help would be appreciated

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I would start with 140 main 55 idle and I would check to make sure but your main venturi's should be 36's unless someone really de sized the carbs for some reason. I have no experience with the MX version of this Weber but don't know why the main Venturi would be so small. Are you sure they are not 40 IDFs instead of 44's? The 44 IDF carbs came stock with 36 venturi's, 135 main, 50 idle and I think 200 air corr. jet with the F11 emulsion and the 50 accelerator pump. The 65 idle is way too big and I bet the plugs are black and the tail pipe in black inside. People over jet the idle to cover up other issues. The plug electrodes should be chocolate brown in color if the jetting is right. Good luck and keep asking questions.

The weber IDA is a much different carb than the Weber IDF. I may be wrong but I thought the Empi HPMX was a copy of an IDF which is much more drivable. The IDA carbs are for all out racing and do better at full throttle or no throttle. The main venturi's my fit them both I dont know. Regardless, you will want to run 36 venturis in your carbs to get the full power your 2110 has on tap. I hate to say that the empi carbs don't have a lot of fans. I have heard more bad than good about them in the vane of all the important air passages not being drilled and other quality issues.

At first, the EMPI carbs were a big bag of suck. They had porosity issues, drilling issues etc.

But that was ten to fifteen years ago when they were first ripped off/introduced. The new ones you get today are much better than before. I'd still prefer Italian or Spanish Webers, but the new ones ain't bad.

Sounds like you're on the right track with respect to jets Speedster Danny. I'll echo Jimmy, you probably want 36 vents, measure them, it may be what you have.

As a point of interest, here's a few pics of @DannyP conducting a Weber Carb Clinic at the annual Speedster Meets Spyders gathering at 2012 Carlisle, PA.

The Weber Doctor is in...DSCN2277

A group of Weber enthusiasts watch as Danny de-mystifies the Weber function...DSCN2282

The group is in awe and gathers closer as they cannot believe that Danny, has in fact, exposed the Weber sorcery!DSCN2280


Images (3)
  • DSCN2277
  • DSCN2282
  • DSCN2280
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