How do you connect the throttle cable to the pedal on a racing go-kart

MrGentry

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I recently purchased a racing go-kart at an online auction. The go-kart had been converted to electric, but I am putting it back to gas. I am curious how I am supposed to attach the throttle cable. It has a threaded rod that runs down the frame and connects to the pedal, and I have a yoke that will fit the threaded rod, but not sure what the set-up should look like when it's done. Any advice/pictures would be appreciated.
The picture is how the threaded rod is currently mounted on the frame.
IMG_20210120_205001697.jpg
 

madprofessor

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Very clean-looking setup there, even though not a fan of threaded rods sliding back and forth through a hole in steel, very rough, kinda stiff, sorta noisy. Still, shame to finish out that pretty train with some trashy setup to reach the motor. Go to BMI Karts website, click gokart parts, click cables, rods, and fittings. Just scroll around to get an idea what's available, you'll get a good idea how it's done right. Then go to youtube, type Predator 212 throttle into the search bar. You'll see tons of videos on rigging up throttles. Skip past the ones that are jury-rigging screws and bent metal together, and stretching long springs all the way across the engines.
 

MrGentry

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Very clean-looking setup there, even though not a fan of threaded rods sliding back and forth through a hole in steel, very rough, kinda stiff, sorta noisy. Still, shame to finish out that pretty train with some trashy setup to reach the motor. Go to BMI Karts website, click gokart parts, click cables, rods, and fittings. Just scroll around to get an idea what's available, you'll get a good idea how it's done right. Then go to youtube, type Predator 212 throttle into the search bar. You'll see tons of videos on rigging up throttles. Skip past the ones that are jury-rigging screws and bent metal together, and stretching long springs all the way across the engines.
Yeah I don't like the threaded rod either and will probably replace it with one from BMI or with one I buy and cut threads on myself. I know how to connect the throttle to the motor, I am just wondering how the connection to the linkage should be made. I have an idea of how, but am hoping someone can post a picture.
 

Dingocat

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Yeah I don't like the threaded rod either and will probably replace it with one from BMI or with one I buy and cut threads on myself. I know how to connect the throttle to the motor, I am just wondering how the connection to the linkage should be made. I have an idea of how, but am hoping someone can post a picture.
Could just run a cable from the pedal back. Would probably require frame mods though.
 

madprofessor

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anderkart's pic shows 2 welded tabs in almost the right config, that is, in line with each other. Unfortunately that wasn't used as intended, with a center-pull yoke or similar that would allow the cable to be pulled in line also. In that same config I'm currently using a piece of flat bar bent 90 degrees at both ends with holes drilled in those ends to give me the "similar" to a store-bought yoke, a straight-line pull. His and mine are both creative answers to make it work with what's on hand at the moment, admittedly the essence of hotrodding.
Pulling any cable at an angle to the sheath's end is never the ideal solution, requires more force to pull, and more importantly makes it harder for the other return spring to retract it. The spring in the pic is only the return spring for the rod, a separate one at the other end of the sheath is needed to retract the throttle itself.. Without that, the rod spring might just bunch the cable right there without actually retracting the throttle on the motor.
You're doing great by using your rigid linkage wherever possible, and only using cable after that part ends. Been through a lot of different kinds of cables and sheaths (conduit) to try to find a combo that doesn't want to get stiff and bind in the sheath when going around a curved section of it. I'd use rigid linkage everywhere if I could, sliding the motor for chain tensioning notwithstanding, but I always settle for just minimal cabling with minimal curves.
MFG S_p_ly (copyright fear) sells me a 1/4" aircraft cabling conduit that has a METAL inner sheath, NOT plastic, and CERTAINLY NOT with no inner at all. It takes at least twice the degree of curvatures that hang up others, and still slides like it was greased. Speaking of which, I also buy "Chain and Cable Lube" from them, yes "Cable", and use its straw to blow lube through the sheath of all my cables. My stuff never hangs up, moves smooth as silk.
BTW: I don't know for sure about anderkart's sheath and compression joint in the pic, but it looks identical to a cheesy setup that was sent to me a good while back. The sheath was just a hollow white plastic tube as his looks above, with the same compression adapter for termination. Problem was the brass adapter had a brass ferrule in it like for rigid plumbing applications, instead of a nylon ferrule like is used on plastic lines. The brass ferrule cut right through the plastic tube when tightened, cut it almost completely off. Kept the very small diameter ball-end cable, threw the rest away.
 

MrGentry

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Looks like someone installed a longer throttle rod in your kart, because it probably used to look similar to this pic:
View attachment 125017L
Do you have a pic of your pedal setup? I'm thinking the pedal tab where my linkage would connect is too high. The threaded rod linkage takes a bend to reach the pedal, which doesn't seem ideal
 

MrGentry

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anderkart's pic shows 2 welded tabs in almost the right config, that is, in line with each other. Unfortunately that wasn't used as intended, with a center-pull yoke or similar that would allow the cable to be pulled in line also. In that same config I'm currently using a piece of flat bar bent 90 degrees at both ends with holes drilled in those ends to give me the "similar" to a store-bought yoke, a straight-line pull. His and mine are both creative answers to make it work with what's on hand at the moment, admittedly the essence of hotrodding.
Pulling any cable at an angle to the sheath's end is never the ideal solution, requires more force to pull, and more importantly makes it harder for the other return spring to retract it. The spring in the pic is only the return spring for the rod, a separate one at the other end of the sheath is needed to retract the throttle itself.. Without that, the rod spring might just bunch the cable right there without actually retracting the throttle on the motor.
You're doing great by using your rigid linkage wherever possible, and only using cable after that part ends. Been through a lot of different kinds of cables and sheaths (conduit) to try to find a combo that doesn't want to get stiff and bind in the sheath when going around a curved section of it. I'd use rigid linkage everywhere if I could, sliding the motor for chain tensioning notwithstanding, but I always settle for just minimal cabling with minimal curves.
MFG S_p_ly (copyright fear) sells me a 1/4" aircraft cabling conduit that has a METAL inner sheath, NOT plastic, and CERTAINLY NOT with no inner at all. It takes at least twice the degree of curvatures that hang up others, and still slides like it was greased. Speaking of which, I also buy "Chain and Cable Lube" from them, yes "Cable", and use its straw to blow lube through the sheath of all my cables. My stuff never hangs up, moves smooth as silk.
BTW: I don't know for sure about anderkart's sheath and compression joint in the pic, but it looks identical to a cheesy setup that was sent to me a good while back. The sheath was just a hollow white plastic tube as his looks above, with the same compression adapter for termination. Problem was the brass adapter had a brass ferrule in it like for rigid plumbing applications, instead of a nylon ferrule like is used on plastic lines. The brass ferrule cut right through the plastic tube when tightened, cut it almost completely off. Kept the very small diameter ball-end cable, threw the rest away.
My tabs on the frame seem to be in a straight line, but the tab on the pedal seems high, requiring a bend in the linkage. It seems to me that ideally the tab would be in a line with, or maybe slightly lower, than the mounting tabs on the frame, but I'm not sure
 

madprofessor

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No good pics of my setup, but it's all custom built, made my own pedals, duals at that because it transforms from left drive 2-seater to center drive single seater, wouldn't be much help. I can tell you that all bends in my throttle setup are at 90 degrees, so no logarithmic? concentric? motion of throttle vs. pedal up to the tab that pulls at the throttle rod/cable setup on the right side. A rod reaches horizontal across from center to right side, pic shows it before cutting to fit, ending in that 3" ? tab. That tab pulls on a bent rod (just like the brake rod on the other side), which pulls straigh-line on my cable with the center-pull "similar" described before.
 

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MrGentry

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I'm not dig'n the angled cable in the pic i posted, I'd prefer a clevis installed in the Yoke for a strait pull instead: View attachment 125036
I have something similar to this, and also purchased a cable with a round mounting hole at the end. The problem I am now seeing is that I won't get much throw on the linkage. Maybe 3/4-1 inch of pull. Not sure if that's enough yet.
 
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