Thunderjet Tuning

Energy One
Yeah I'm going to start again in a couple days because I need more jets. S&S does not make any jets between 33 and 36 and I should be running a 34 or 35. I called Zippers and they have those special sizes. According to Zippers I should be at a 34 or 35 int. with a 74 main. I'm starting to get some old weber carb deja vu going on
 
being the machinist Al is, surprised he doesnt drill his own. :up:
I thought about it because I still have 2 small drill bit sets from when I had the weber carb and I had to drill my own jets then. But I want to be able to switch back if I had to. My jet supply is running low due to cheapskate friends keep using mine up.
 

Chopper Dave

SIICK!!!
I thought about it because I still have 2 small drill bit sets from when I had the weber carb and I had to drill my own jets then. But I want to be able to switch back if I had to. My jet supply is running low due to cheapskate friends keep using mine up.
Al...what size jets do you need? to drill....my dad gave me a pack of jets from his G carb(I would have to see what sizes are in that pack he gave me) he had on his Harley...plus I also I the high end jet kit....give me a call and let me know and I will send you those jets.....
 
Al...what size jets do you need? to drill....my dad gave me a pack of jets from his G carb(I would have to see what sizes are in that pack he gave me) he had on his Harley...plus I also I the high end jet kit....give me a call and let me know and I will send you those jets.....
Thanks Dave for the offer but I have them coming already but if I need more I 'll give you a shout.
 
Well I did about 8 different jet changes today but I finally think I got it. This thing is really waking up now. I'm also more inline with what zippers suggests. I am now running a 33 slow jet, 74 main jet, and a 135 (.053) air bleed and a 120 thunder jet. I think I was underestimating the impact the airbleed has on the main jet. For example I needed a 80 main jet with a 155 (.061) airbleed. Just by dropping the air bleed I was able to drop down to a 74 main but then I had to up the thunderjet from a 100 to a 120. Now I can do some great 2000 rpm roll on's. I coast in second gear up to 2000 rpm's and punch it full throttle and break the rear tire loose. I can't get back on the dyno till the 16th of June so I'll wait till then and see if my lean condition at high rpm's is fixed. Hell I might have even picked up a couple pony's.
 
sounds great! :up:

did you get the LM-1 on her yet?
Yeah but I'm going to kill myself with that fucker, I cant keep the bike rolling at 5000 rpm's and keep watching the meter. I think it works fine on the low and midrange but its tough keepin your eye on it while getting on it, and you need to maintain those rpm's for a few seconds till the air fuel levels out. I think when I get back to work I'll invest in the recorder as well. That way all I have to do is ride it all around then I can download the data after.
 

Raywood

The Pirate
Staff member
Calendar Participant
Troop Supporter
Well I did about 8 different jet changes today but I finally think I got it. This thing is really waking up now. I'm also more inline with what zippers suggests. I am now running a 33 slow jet, 74 main jet, and a 135 (.053) air bleed and a 120 thunder jet. I think I was underestimating the impact the airbleed has on the main jet. For example I needed a 80 main jet with a 155 (.061) airbleed. Just by dropping the air bleed I was able to drop down to a 74 main but then I had to up the thunderjet from a 100 to a 120. Now I can do some great 2000 rpm roll on's. I coast in second gear up to 2000 rpm's and punch it full throttle and break the rear tire loose. I can't get back on the dyno till the 16th of June so I'll wait till then and see if my lean condition at high rpm's is fixed. Hell I might have even picked up a couple pony's.
:cheers: :2thumbs: :cheers:
 

lee

Well-Known Member
good work Al. I know what you mean about the LM unit too! Lethal. I tried to record onto a SD card but no joy. No idea how that works. Probably wouldn't have been much use anyway because I don't have the rpm cable.
 
good work Al. I know what you mean about the LM unit too! Lethal. I tried to record onto a SD card but no joy. No idea how that works. Probably wouldn't have been much use anyway because I don't have the rpm cable.
Mines a little older unit s no SD card, but the internal memory can hold 45 minutes of data. But like you said unless you can associate the air fuel readings with engine rpm's the data is useless. You have to buy the "aux box" for the LM-1 that costs another $249.00 and then find places to hold 2 boxes when you ride.
 

outdoorsman26

Well-Known Member
how did this all turn out for you?? I am currently doing this mod to my carb and was wondering what jets you settled on??
 

outdoorsman26

Well-Known Member
just seen that AL hasn't been on here in a while does anyone know what jets they are running in there carb with the thunder jet?? I have stock motor w/600 cam and V&H pipes, thanks
 

Wolfman Dan

New Member
Well I did about 8 different jet changes today but I finally think I got it. This thing is really waking up now. I'm also more inline with what zippers suggests. I am now running a 33 slow jet, 74 main jet, and a 135 (.053) air bleed and a 120 thunder jet. I think I was underestimating the impact the airbleed has on the main jet. For example I needed a 80 main jet with a 155 (.061) airbleed. Just by dropping the air bleed I was able to drop down to a 74 main but then I had to up the thunderjet from a 100 to a 120. Now I can do some great 2000 rpm roll on's. I coast in second gear up to 2000 rpm's and punch it full throttle and break the rear tire loose. I can't get back on the dyno till the 16th of June so I'll wait till then and see if my lean condition at high rpm's is fixed. Hell I might have even picked up a couple pony's.
Hey Al, I'm curious if you are still on this forum. I know this thread is old, but I'm getting ready to install a S&S Super E already modified with a Thunder Jet. Could use all the advice I can get. I also have a Kuryakyn Super Charger Air Intake on mine. There is very little information about this combo. Any advice?
 
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