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Another E to G Thunderjet thread

Discussion in 'Performance' started by SEAL-rider, May 24, 2017.

  1. SEAL-rider

    SEAL-rider Member

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    I realize there are many threads that discuss the Super E carb and the considerations around transitioning from Super E to G; but I hope my short story might help new folks making carburetor decisions. My 2005 Chopper came with an E carb with restrictor plates and all the other wonderful tuning decisions the EPA could muster. Working with Curtis at Wild Steed Worx we fixed many issues, and upgraded to 585 cam with a Thunder Heart programmable ignition which combined for noticeable improvement. But the bike just seemed to be starving above 4k and rich below. It had horrible decel pop below 3k. We tried various jetting combinations but Curtis continued to council the need for more air - ie more carb. So I looked at the Triple X. There were valid reasons to go XXX Super E and equal arguments to go to the XXX Super G carb. I also considered just a stock G carb. In the end I chose to send a stock Super G to John Sachs. John focuses the budget on functional benefits so I saved money. In other words, he doesn’t send out a highly polished carb like the Triple X, but he does an awesome job boring it out and adding the ThunderJet among other upgrades


    Thunder-Jet? There are many debates and opinions on the need or benefit of the TJ, but it just made sense to me. Where a 78 jet might be rich at 3k, it provides the needed fuel above 4k. But the 76 while perfect below 4k is starving above. Hence the Thunder-Jet. It allows you to drop the main jet and fill in all the fuel you need at higher RPMs. Sounds great in theory, but I had many people tell me it was a dumb idea and why did I think I knew more than S&S engineers.


    Well, the result is nothing less than amazing. I am riding a new bike. All decel pop is gone. I can’t tell the difference in the smoothness of 3500k or 4500k. It just pulls and pulls with seamless transitions between jets. I started with a 31/78 100 Thunder-jet. It felt a little flat above 4k so I dropped the main to 76 and upped the TJ to 120 thinking I needed to compensate to maintain the top end (wrong). Finally, I settled on 31/76/100TJ. It is amazing. As if I had an underweight starving Greyhound that I fed for the first time. It just runs like a beast.
     
  2. Th3InfamousI

    Supporting Member

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    Glad to hear you up and running...


    i looked into the mod but for the amount of times I actually go north of 4000 RPM well hell it's pretty rare. Maybe seen the yellow part of the tach I don't know maybe once or twice a year if that.

    I would however like to just have the carb bored and the air bleed moved to the outside. Did John drill and tap the air bleed to be external?




    Sent from my 2PS64 using Tapatalk
     
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  3. SEAL-rider

    SEAL-rider Member

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    He did add the external air bleed and finger air/fuel screw. I added the extended float bowl bolts. While I focused on performance abobe 4k, the bike simply runs better everywhere. Your should reach out to John. I am very happy with his upgrades.
     
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  4. Th3InfamousI

    Supporting Member

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    That external air bleed is a neat little nice to have that's for sure. Wish I had that now so I can dial in these new pipes easier.

    I also think the previous owner over tightened the idle mix screw because it really doesn't do shit. All the way in...or out it doesn't stumble. I know that can be rebored and fixed too.
    Sent from my 2PS64 using Tapatalk
     
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  5. SMCT

    SMCT Active Member

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    Thanks for the heads up. I have a XXX with the dual Thunder jet set up. I just haven't had time to bolt it on.
     
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  6. BadDawg Bill

    BadDawg Bill Well-Known Member

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    John Sachs is a genius with motors and parts. Ya, he can help ya out for sure..... and he lives right up the road from me!!!
     
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  7. FrankBDPS

    FrankBDPS Well-Known Member

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    John did the carb for my 107. It pulls hard all the way thru the gears. You can actually feel the thunder jet opening up. Great work John.
     
  8. john sachs

    john sachs Active Member

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    Thanks guys.
    John
     
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