Weight and power? Avg weight and power? Ratio?

leiget

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What are some weights, or even and average weight, for single-seat off-road gokart/buggy?

For something around 500 lbs, how would the Predator 420cc 18.5 ft/lbs and 13 HP engine do?
 

G.W

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I am not sir how to answer this question. I have a single seat Murray full sus6buggy, but I haven't weighed it. I am going to mount a 459cc predator soon. It ran about 25 witha 212 and 4.2 to 1 ratio.
 

Denny

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What are some weights, or even and average weight, for single-seat off-road gokart/buggy?

For something around 500 lbs, how would the Predator 420cc 18.5 ft/lbs and 13 HP engine do?
If we are talking 500lbs kart and rider it would be a rocket with a 40 series CVT and proper gearing! If you are talking 500lbs just for a kart then that’s the size engine you should be using already with the 40 series and proper gearing.
 

leiget

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I've not completed it yet, but I weighed it with a scale on the front and back, and they add up to about 350-400 lbs. It'll be about 450-500 when done. I'm 240 (chucky booooy).

The gear ratio I plan on is about , 10 teeth on the 40 Series to a 60 tooth axle gear, so a ratio of 6:1. I'm also going to modify the governor to limit at 4200 RPM if possible. The max possible speed would be 48 MPH.

At low gear on the CVT the ratio is 2.43:1, so I think that the final torque, at the wheels, would be 23.5 ft/lbs. Don't know for sure, I just tried calculating it without knowing for sure how to do so heh.

But the top speed it about what I want, but if I need a bigger axle gear, then no problem.
 

BaconBitRacing

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I've not completed it yet, but I weighed it with a scale on the front and back, and they add up to about 350-400 lbs. It'll be about 450-500 when done. I'm 240 (chucky booooy).

The gear ratio I plan on is about , 10 teeth on the 40 Series to a 60 tooth axle gear, so a ratio of 6:1. I'm also going to modify the governor to limit at 4200 RPM if possible. The max possible speed would be 48 MPH.

At low gear on the CVT the ratio is 2.43:1, so I think that the final torque, at the wheels, would be 23.5 ft/lbs. Don't know for sure, I just tried calculating it without knowing for sure how to do so heh.

But the top speed it about what I want, but if I need a bigger axle gear, then no problem.
Pretty sure you calculated the wheel torque wrong, 13ft/lbs is a reasonable estimate for engine torque, though it may make more. Then multiply that by 6 equals 78 then factor in the TC low gear.
 

Denny

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I've not completed it yet, but I weighed it with a scale on the front and back, and they add up to about 350-400 lbs. It'll be about 450-500 when done. I'm 240 (chucky booooy).

The gear ratio I plan on is about , 10 teeth on the 40 Series to a 60 tooth axle gear, so a ratio of 6:1. I'm also going to modify the governor to limit at 4200 RPM if possible. The max possible speed would be 48 MPH.

At low gear on the CVT the ratio is 2.43:1, so I think that the final torque, at the wheels, would be 23.5 ft/lbs. Don't know for sure, I just tried calculating it without knowing for sure how to do so heh.

But the top speed it about what I want, but if I need a bigger axle gear, then no problem.
Sounds like you have a good solid plan! It should work great!
 

student👍

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i always wear lethar or converse style shoes for karting
personally i feel like the right shoes can make a difference in how you drive

lol sor that was so off-topic
 
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G.W

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i always wear lethar or converse style shoes for karting
personally i feel like the right shoes can make a difference in how you drive

lol sor that was so off-topic
Shoes do make a difference. Wearing boots gives no room for fine adjustments, I prefer convers or leather shoes for driving in general because I can make adjustments easily
 
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leiget

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Pretty sure you calculated the wheel torque wrong, 13ft/lbs is a reasonable estimate for engine torque, though it may make more. Then multiply that by 6 equals 78 then factor in the TC low gear.
Oh, it's that simple? Okay then.

The engine puts out 18.5 ft/lbs at 2500 RPM, so the final torque (including with the 23" tires) should be 106 ft/lbs, which sounds much better than 23.
 

BaconBitRacing

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Oh, it's that simple? Okay then.

The engine puts out 18.5 ft/lbs at 2500 RPM, so the final torque (including with the 23" tires) should be 106 ft/lbs, which sounds much better than 23.
Yep that'll haul ya. 23 inch rear tires like to cause problems for people who don't plan. What's the driven TC shaft diameter? 3/4 or 5/8?
 

student👍

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i think my kart is slightly lighter than me by like 40 or so lbs
but im currently gaining so that's why im moding
turns fast as heck though
maybe too fast
 
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G.W

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My kart is way heavier than my bike. My bike wighs maybe 100 lbs total. It is surprisingly light
 

student👍

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as colin chapman said "simplify then add lightness"
you're fine though ur engine should make up for it
but still simplifying the kart could make it significantly lighter
 

G.W

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as colin chapman said "simplify then add lightness"
you're fine though ur engine should make up for it
but still simplifying the kart could make it significantly lighter
Trust me, my kart is very simple, but it is a factory full suspension.
 
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