treyfus
New member
here it is, i dont plan on going too crazy with it, probably an 80 lb motor and i weigh 145.
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Doc Sprocket
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If you're a competent welder, I think it'll be okay.
treyfus
New member
i suppose it would probably take a large amount of force to permanantly deform any of this steel, the 16 gauge will probably flex a bit more, but since its suspension components on the front there isnt a whole lot of weight on top of it. i will take my time welding and do it right. what speeds could i expect if i used one of those 16hp duromax clone motors with a comet 40? the youtube videos werent very impressive, which kind of puzzles me due to the large hp ratings, i mean the racers use the 5 and 6 hp motors that will run 60+! i guess its all in the gearing?
Doc Sprocket
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Gearing has very much to do with it. So does weight, RPM, tire size, and expected performance over specific terrain. 6.5hp race karts are very light, and run on a dead smooth track. Once they get going, they keep going. Also- race engines tend NOT to stay at the original horsepower, nor are they limited to 3600RPM.
To put things into perspective, this was my set-up for 4 years. 11hp Honda GX340, bone stock except for a custom-made muffler, and governor tweaked to 4200RPM. Comet 40 CVT. 4.8:1 final drive ratio, 17.5" (measured) rear tire diameter, combined kart and rider weight of about 450lbs. GPS and speedometer verified top speed of 46MPH.
Now- this is an off road kart. I could have geared higher for more speed, at a loss of low-end torque and acceleration.
To put things into perspective, this was my set-up for 4 years. 11hp Honda GX340, bone stock except for a custom-made muffler, and governor tweaked to 4200RPM. Comet 40 CVT. 4.8:1 final drive ratio, 17.5" (measured) rear tire diameter, combined kart and rider weight of about 450lbs. GPS and speedometer verified top speed of 46MPH.
Now- this is an off road kart. I could have geared higher for more speed, at a loss of low-end torque and acceleration.
treyfus
New member
this is very interesting, i would love to set mine up like that. so if i did get the 16 hp with 20'' tires and a similar gear setup i could expect similar results due to yours being slightly modified...did you feel yours had pretty good response and acceleration?
Doc Sprocket
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I'd advise staying to 18" tires or less, they really do rob power. I realize you are thinking about a 16hp, as opposed to my 11, but that 16hp will also weigh a lot more. Everything is a compromise...
Performance was really about as good as I could expect, given the overbuilt heavy chassis. It was originally geared at 4:1, which was too high. I fiddled with the CVT driven's shift characteristics, and finally regeared. It was quite an improvement.
I have since removed and sold the gx340. Once I again have some free time, I have a 250cc V-twin Virago engine and tranny going on it.
Performance was really about as good as I could expect, given the overbuilt heavy chassis. It was originally geared at 4:1, which was too high. I fiddled with the CVT driven's shift characteristics, and finally regeared. It was quite an improvement.
I have since removed and sold the gx340. Once I again have some free time, I have a 250cc V-twin Virago engine and tranny going on it.
treyfus
New member
thats the truth. 2 strokes would be awesome but they are loud vibrate a lot and arent made to idle. a vtwin motor would have much more torque, i really should try to look for one, i should get what i want now so that i wont have to waste money on a lesser motor and re-engineer motor mounts. yea i am very familiar with regearing due to change in tire size, i did it on my truck. went from 28'' tires with 3.42 gears to 33'' tires with 4.10 gears!what sprockets did you use on that
Doc Sprocket
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10T and 48T.
The bike engine I have is a free air 4 stroke. I may build a shroud, and/or engineer a cooling fan.
The bike engine I have is a free air 4 stroke. I may build a shroud, and/or engineer a cooling fan.
treyfus
New member
that would be a good idea. v-twin motors are very expensive new, 1000 dollars for a clone 20hp! that seems like a rip off.
Doc Sprocket
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It really is. Whenever folks ask me about alternative engine solutions, I suggest shopping for an old motorcycle. An industrial engine is great if you want traditional kart, or a race kart for a specific class. But if you're building a buggy or something that requires a "special" powerplant, don't use an industrial engine unless you already have it or can get it dirt cheap. Used bikes can be had all day long for much less than a big industrial, and there are many benefits- the biggest being the transmission. Furthermore, if you work things carefully, you can not only get your engine free, you can MAKE money on the deal. How? Shop carefully. Get a good deal on a runner, take the engine and whatever else you want. Now, break the bike down and sell the parts. Folks will pay good money for a straight frame with a title. Good body parts fetch good bucks. Good forks are worth money. Tires and rims. Nice tanks, too. You got it, sell it. It may take some time and effort to recoup your money, but it is very doable!
Pound for pound, cc for cc, EVEN hp for hp, a bike powered machine will kick the snot out of an industrial engine powered machine.
Pound for pound, cc for cc, EVEN hp for hp, a bike powered machine will kick the snot out of an industrial engine powered machine.
treyfus
New member
the more i keep reading into motors and clutches the more i believe you! that 16 hp motor (300$) will need a torque convertor (300$) thats 600 dollars for a decent ride...i could get a wrecked bike or even a good older bike for that much. in your experience, is it simple to rig up the clutch and shifting mechanism on a go kart? the traditional foot peg wouldnt be a good option then you would need 4 pedals! hahaha.
treyfus
New member
i was looking around for torque converters that werent stupid expensive, i found these:http://www.ebay.com/itm/1-GO-KART-TORQUE-CONVERTER-CVT-CLUTCH-Replaces-COMET-TAV2-30-100-218354A-TAV-2-/230710593998?pt=Go_Karts&hash=item35b76c49ceit says rated up to 13hp, the 16hp duromax motor was the one i was leaning towards, is this junk? Thanks!
Doc Sprocket
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I would NOT trust that CVT to hold up to 16hp. I don't know who manufactured it, and you'd be exceeding the max input power. There's a user on here who has exceeded his max input power with a similar unit, and was chewing up belts all over.
I love sellers that have no idea what they're talking about. The description boasts, "This clutch will help you get more power of your small engine by reducing engine load with nearly a 10 - 1 overdirve. A torque converter acts similar to a transmission, allowing higher speeds of your small engine, and smoother acceleration."
First, that's underdrive, NOT overdrive. If it had a 10:1 overdrive, you wouldn't move. Furthermore, this idiot has no idea what he's talking about. The engagement (low) ratio of this unit is 2.7:1, NOT 10:1. Second, it's not a "clutch" that "acts similar to a transmission", it is a power transmission that features a clutching function. Third, it does NOTHING for engine speed, and fourth- smoother acceleration? WTF? Get bent. Oh yeah- and fifth- you do NOT get "more power" out of your engine. It makes better use of the power that IS available, through gearing. Gearing down divides speed and multiplies torque. Conversely, gearing up multiplies speed and divides torque.
Engineering the clutch and shifter really isn't that difficult. The bike clutch will be either mechanical (cable) or hydraulic. Either method lends itself well to remote mounting. Most folks would go to a pedal, but some guys will mount the bike's clutch lever to the new shift handle.
The shift mechanism will require a mechanical linkage, which will require some thought and engineering. Don't worry though- when you reach that point, we'll guide you through it.
I love sellers that have no idea what they're talking about. The description boasts, "This clutch will help you get more power of your small engine by reducing engine load with nearly a 10 - 1 overdirve. A torque converter acts similar to a transmission, allowing higher speeds of your small engine, and smoother acceleration."
First, that's underdrive, NOT overdrive. If it had a 10:1 overdrive, you wouldn't move. Furthermore, this idiot has no idea what he's talking about. The engagement (low) ratio of this unit is 2.7:1, NOT 10:1. Second, it's not a "clutch" that "acts similar to a transmission", it is a power transmission that features a clutching function. Third, it does NOTHING for engine speed, and fourth- smoother acceleration? WTF? Get bent. Oh yeah- and fifth- you do NOT get "more power" out of your engine. It makes better use of the power that IS available, through gearing. Gearing down divides speed and multiplies torque. Conversely, gearing up multiplies speed and divides torque.
Engineering the clutch and shifter really isn't that difficult. The bike clutch will be either mechanical (cable) or hydraulic. Either method lends itself well to remote mounting. Most folks would go to a pedal, but some guys will mount the bike's clutch lever to the new shift handle.
The shift mechanism will require a mechanical linkage, which will require some thought and engineering. Don't worry though- when you reach that point, we'll guide you through it.
treyfus
New member
thank you for that explanation...I think those comets are way overpriced for what they are. My friend has an older vtwin 600cc suzuki mid 80s model he was restoring and lost steam on it. I heard it run myself. May be a good option if I beef my kart up a bit.
Doc Sprocket
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...Beef it up a LOT. That's a lot of engine.
Let's clarify something that I feel strongly about. The "Comets" may be pricey, but well worth the money for the right purpose. I beat the snot out of my Comet 40 for four years without so much as a hiccup. Performed like a dream, zero maintenance.
The CLONES of Comets are a whole other story! I wouldn't buy the one you linked to even with a gun to my head.
Look up CVTech CVTs if you want to see gnarly pricing.
Let's clarify something that I feel strongly about. The "Comets" may be pricey, but well worth the money for the right purpose. I beat the snot out of my Comet 40 for four years without so much as a hiccup. Performed like a dream, zero maintenance.
The CLONES of Comets are a whole other story! I wouldn't buy the one you linked to even with a gun to my head.
Look up CVTech CVTs if you want to see gnarly pricing.
treyfus
New member
i see. im just always looking for the best alternatives, even when there isnt a better one. goodness now THAT is expensive!
treyfus
New member
i have been looking around at different kart and buggy plans. the edge plans seem to be well thought out and solid. the trax 2, taipan, and sidewinder look to be very nice. they quote these karts at up to 3000$$$ do build... am i reading that wrong?! thats without drivetrain. haha they just seem like simpler stronger karts, whereas the arachnid looks fragile in comparison.
r97
Measure twice cut once
IMO, steer well clear of spider carts.
Edge buggies are definitely built much stronger. I was turned away by the larger dimensions, weight, cost, and not having access to metric sized steel stock.
Edge buggies are definitely built much stronger. I was turned away by the larger dimensions, weight, cost, and not having access to metric sized steel stock.
treyfus
New member
ok thank you. so your building your own custom then? i hope you love it! modeling it after anything or are you totally engineering it yourself?
r97
Measure twice cut once
I'm kind of taking the styling from the sidewinder, although dimensions, suspension, and power plant are all being designed by me.
http://www.diygokarts.com/vb/showthread.php?t=14403
http://www.diygokarts.com/vb/showthread.php?t=14403
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