Does this sound right?

[Renegade]

Aight, yal just tell me what ya think please... I was searchin the web for designs i liked that looked relatively cheap but cool lookin and ended up on Spider Carts website. Meand my 8 year old agreed on the tarantula. The thing looks easy enough to build without orderin the plans (Im hell with legos, lol) seriously im no stranger to fabricating and im a 4 wheeler mechanic by trade, besides i was gonna modify the plans a little anyway to come up with a mix between the tarantula and the arachnid... although more based on the tarantula i wanted to incorperate a mild front suspention on it with single a arms, one of my concerns was the speed of this thing. Its pictured with a 60 tooth rear sprocket and 12 on the front clutch, any ideas how fast this thing will top out at or how hard it will pull out the hole with just a 6.5 hp motor on it, im debating on a 10hp but being a go cart im not sure about speed and gearing, im intending on using 18in rear lawnmower tires, well, now that i think of it i may just sit the craftsman up on blocks and jank all the tires off her! Anyway just let me know what yall think... and yeah i guess its for me as much as my oldest son but hey... at 8 years old he drives my Can Am Renegade by hisself all the time. What can i say, its in his blood.

 

[r_chez_08]

If this kart is primarily for the 8 year old, then 6.5hp should be plenty. I would gear for approximately 15mph, and then you can always regear later if they find it too slow.
See this link:http://diygokarts.com/speed-calculator.html
You may require a jackshaft to gear the kart down further as your gearing may require a rather large rear sprocket.

 

[Renegade]

Well... ha ha, guess ya caught me! Long story short i ride atv's alot, went riding with my buddies the other day and 2 were on golf carts, i switched up with 1 of em and just decided i wanted somethin else to ride besides an atv, and a golf cart is way to slow, My boy will probably ride it some but primarily me and just on dirt and back roads. Ill be specific about what im looking to accomplish. I want this thing to run around 50mph, have good torque and even more fun factor. I got access to a 10hp side shaft briggs but not against gettin an equivilant predator from harbor freight. I plan on using 18in tall rear tires and a lil smaller front tires. Pretty sure i can handle the front, just need advice on the back. I wanted to use a live axle(keyed) with disk brake and just run the chain from motor to axle like in the pic. I also wanted to use the typical classic go cart clutch/ sprocket. With the 6.5 the plans say 12 front 60 rear... id love to know how that performs and even more so with a 10hp. I am sorry for my lak of knowlege on this, Id love to be able to finish this thing though but the rear end and gearing is what caused me to scrap my mini buggy project and i just dont this to go the sape way.

 

[Renegade]

Did the calculator, with a 12 tooth clutch and 45tooth rear, 18 in tires and 3600rpm it would hit 51, question is how long would it take to get there with a 10hp motor. Anyone out there runnin a similar setup?

 

[Bluethunder3320]

for an 8 year old? dang. wont be able to get that with a centrifugal clutch..

 

[r97]

well according to this calculator, with a 265lb total weight, it will take you 325ft of flat ground,
http://gokartguru.com/engineering_tool_kit.php

Of course that is all theoretical, you will not be reaching 50mph, and your clutch is going to be screwed.

your going to need to either settle for much less speed, or look into a better drive train. bigger engine, a multiple speed transmission (CVT maybe). a dirt bike engine might be what your looking for.

 

[Doc Sprocket]

with a 12 tooth clutch and 45tooth rear, 18 in tires and 3600rpm it would hit 51,

Not going to happen, except off a cliff. Please keep in mind that gearing calculations are theoretical, and based on the assumptions that the engine has sufficient power, the clutch can tolerate the abuse, and several other factors.

Your calculated ratio is far too tall for the reality of what you're building.

True life example, might help you- My stats

Weight- 340+lbs with driver
Rear rubber- 18" advertised, 17.5" measured
Engine- Honda Gx340, 11hp
Clutch- Comet 40 CVT, delayed driven
Final drive ratio- 4.8:1 (10T, 48T)
RPM- 4200-ish
Max speed- (per GPS and Speedo)- 45.5 MPH

The reality of it-

Acceleration tended to be a bit more sluggish than I'd like, so I really was at the highest gearing that I'd want to be. If I wasn't changing drivetrains, I would have regeared lower, to 5.2:1 or maybe 5.4:1.

In short, had I geared to approx 4:1 like you propose, I would never reach it. In fact, I WAS geared 4:1 (12T, 4.8T), and my max speed was actually slower due to the engine not having sufficent power to meet the load demands, and therefore never reach peak RPM.Hope this helps illustrate things for you.

 

[r_chez_08]

Buy a 40 series for the 10hp and you could reach 35-40mph (coming from me who has his 6.5hp clone and 40 series clutch geared for 44mph offroad!)

 

[Renegade]

Ok, now that im seeing the reality of it yeah i reckon my expectations were way out there... 35-40 top end more realistic sure i can handle that, but im trying to stay away from jack shafts and cvts. So would a 12 tooth clutch and 66 axle be a better choice? calculator says 36 on top and i can live with that long as its bretty snappy, and will a typical go cart clutch hold up with this setup...... Also i just want to thank all yall for ya replys and help on this, instead of just lettin a noob screw this up and waste time and money yall jumped on in and helped, helluva lot more than i got on other forums (reguardin mini buggy building)! Thanks!!!

 

[Doc Sprocket]

You might be a little closer to reality with that. The 18" tires are quite a load though. My advice FWIW- buy a high quality clutch like a Noram, gear down a bit more, like 72 on the axle, and adjust the governor out to max, which is generally 4100-4200 rpm.

 

[Renegade]

thanks for that info bro, been checkin on axles and chains and not sure weather to get 3/4 or 1in axle shaft and either a 35 or 40 chain... obviously the bigger the better i reckon...lol, as for the tires they aint heavily treaded or nothin, just rear lawn tires, figured that would add to the fun factor slippin and slidin round! Looked at the noram clutches too, dand that cheetah looks sweet!, but they like it too, one thing i learned though is ya gotta pay to play, but would the GE or GE ultimate work? Oh forgot to mention one thing at the beginning of this thread... Im 6'1, 220 lbs... am i too big for a go cart...LMAO!

 

[machinist@large]

Oh forgot to mention one thing at the beginning of this thread... Im 6'1, 220 lbs... am i too big for a go cart...LMAO!

Halleluiah!!! Welcome Brother!!! (I'm 6'4", 250 lbs; I'm feelin' for ya!!)

 

[fowler]

if u are an atv mechanic by trade then try to find an old bike motor
that will work far better than any cent clutch or comet tc

 

[getting kart smart]

Did the calculator, with a 12 tooth clutch and 45tooth rear, 18 in tires and 3600rpm it would hit 51, question is how long would it take to get there with a 10hp motor. Anyone out there runnin a similar setup?

Tried that. You cant gear that high with a centrifugal clutch. You will smoke your clutch. You will need to get a torque converter and a jack shaft. You can play with your gears on the Jackshaft to get the speed and torque you want.

 

[qtband]

I am in agreement with the rest of the posters. I had 15" tires with a 60T sprocket, 8hp, cent. clutch and it only could go down hill! LOL!!!! Spend the extra for a torque converter and you'll be MUCH better off. Or as others said, put a bike motor on it and don't tell the kid how to get out of 2nd gear!

 

[bighead]

An old ATC (atc110) engine may work. They have low and hi gear range as well. You can pick them up really cheap as well. They have large tires and loads of torque. I am cose to 275 an my ATC110 will carry me up hill all day. Auto trans as well.

I have a complet Honda FL250 J-arm front suspension for sale. Complete from tires to steering wheel with controls.

Been wanting a person to use an Ody front end for a long time now. With this setup you have hand controls for the little ones. Although 8 year older may have a problem with grip for the brakes. On the throttle side you can rotate the lever down to set the throttle for the 8 yeal old. Take out the screw and rotate the lever on the spline.

You would need to locate the cross bar the J-arms slide onto. I have everything else.

You get:

Steering Wheel with brake and throttle levers
Steering column
Steering shaft with pitman arm.
Shocks
Tierods
J-arms
spindles
hubs
wheels
Okay tires

$75 plus shipping.

Parts are the same as these pics below but in original condition. Not sure if it works for what you want to do. But you kill a lot of birds for $75.

 

[landuse]

thanks for that info bro, been checkin on axles and chains and not sure weather to get 3/4 or 1in axle shaft and either a 35 or 40 chain... obviously the bigger the better i reckon...lol, as for the tires they aint heavily treaded or nothin, just rear lawn tires, figured that would add to the fun factor slippin and slidin round! Looked at the noram clutches too, dand that cheetah looks sweet!, but they like it too, one thing i learned though is ya gotta pay to play, but would the GE or GE ultimate work? Oh forgot to mention one thing at the beginning of this thread... Im 6'1, 220 lbs... am i too big for a go cart...LMAO!

A 1 inch keyed PTO means that will have far less options regarding cent clutches, and they will be really expensive. A 3/4 PTO has loads of clutch types you can choose from, as well as being cheaper. A 40 chain is stronger, but personally I would only really use it if you are building a big offroad kart with loads of power. To be safe though, just go with the #40.

Just make sure when you buy sprockets and chain that they are all the same pitch. You don't want to be getting a #35 clutch and a #40 sprocket by mistake.