kool go kart help

[saladtossser]

ok i'm in this friendly competition to make a cart, i dont wanna race just for fun

my dad is a very demanding person, i need the engine but he will only pay for one if i showed that i made effort to finish the body of the cart, so he doesnt "waste money" if i "whimp out"
so i better get this right, since i dont have an engine to work off of
oh and i want everything to be bear mininum, no room for "just to be sures" and "margin of error", i'm short of cash

heres a few pictures of what i plan
see
the d3 design is the one i wanna try
i am confident that design will hold up, yellow is 1/2" thick plywood, the dark grey stuff is those L shaped steel rails with predrilled holes
steerings is a no-brianer

complex said if i use a 6.5 hp engine (most likely) i need a 7.5:1 gear ratio, my wheel diameter is 6", i want to go at 30 kph
30 kph=19685 inch per minute, circumference of wheel 6*3.14=19
19685/19=1036
so i want 1036 rpm on the axle
engine max is 3600 rpm (correct?)
math tells me i want a 3.5:1 gear ratio
i estimate the cart to weight 150 kg with me included
is 6.5 hp enough? if not, what is?
also i see some go karts being sold, 6.5 hp, 6" wheels, something like 40 kph, so with my horrible noobish skills, a 6.5 hp, 6" wheel, 3.5:1 gear ratio cart certainly could do 30 kph right?

do i want roller bearings or are ball bearingsgood enough for 1000rpm?

i want the drive train to be simple, gear on engine, chain, gear on axle.
is a clutch a must? will an engine idle even though it's shaft stop spinning?
or can i use a belt to solve this? as it will just slip on the pulley and continue spinning after i stop
and i know i can get a clutch if it is needed but is there anything specific i should ask for?
and how do i mount one?

what wheel should i use? metal with rubber tires? metal with urethane tires? plastic with rubber tires? plastic with urethane tires? plain plastic/rubber/urethane/metal? i think plastic with rubber will do, but you guys are the pros, what do you think is bear mininum?
EDIT i found two 6" plastic wheels, not good enough, no traction

if the engine comes with a muffler, it's useless right? i dont care about noise, i mean, come on, i shoot spuds for a hobby

oh, and this has to be made with out any welding or machining

and if you care enough
http://www.reliablebearing.com/
is a 30min walk from my place
sells gears pulleys chains belts wheels motor bearings clutch pneumatics and other stuff + machining, cnc mill lathe they have it
it's like a all in one place for go karts except no hardware or engines

[jrrdw]

Yes you need a clutch, no matter how you decide to set it up. In your case the simpler the better, get a centrifical clutch that goes rite on the crankshaft, it should allready be taped so the center bolt will hold it on. Yes 6.5 will kick butt with a centrifical clutch. Yes leave the muffler on that came with the engine you will get BETTER PREFORMANCE TRUST ME!!!! If your refering to axle bearings, roller ball bearings are stronger, in this case rule of thumb is YOU GET WHAT YOU PAY FOR!!! As for the bolt together design, use lock nut AND lock washers with them, or you will be forever retighting them. Wheels-depends on rideing surface, but i recamend steel rims and rubber tire setup, pneumatic of course, not solid, pneumatic with give you some shock asorbance, good luck, WIN WIN WIN your contest, let me know if your have any other questions.

[saladtossser]

i have some crapy hollow plastic 6" wheels that i used for looks, they suck, i might actually use a 7:1 gear ratio and double my wheel size.

but most likely i wont, but i need give the cart too little clearance, the front wont touch the ground until i trim a bolt down

for the nuts and bolts, too late, i've already started wit lock washers but regular nuts, dont worrie i never forget maintance on anything
i still have a chance to replace them i guess

in other news, the right front wheel is on, although i might replace the wheel

stupid me cut the clearance for the wheel too big

can i make my own clutch? i saw some pictures and i thought, a few levers, a few adjustable springs, and rubber stuff...
do some special sprockets come with a built on centrifical clutch?

[jrrdw]

Check this link out from top to bottem, this is where i get all my lawnmower repair parts http://www.jackssmallengines.com/clutches.cfm well most of the, they don't do John Deere or Cub Cadet. They will send parts anywhere far as i know.

[saladtossser]

woot got a champion brand 6.5 hp engine! shiny and new from costco and only $140 canadian!!!

gonna go clutch hunting soon, got a hand full of companies to call up, thx dude

this might turn out nice after all, i will cover the wood up with some sheet metal to hide the crappyness of plywood

the L shaped steel beams are not strong enough, i'm switching to square.
my dad is getting a metal cutting blade for our mitre saw
dollar store saws SUX especially with a dull blade.

[Benny]

6.5? i cant wait to see it.

[jrrdw]

Yea with a good clutch it's gonna rock out! Get some good pics up. Afer all this talk, i'm excited to see how it turns out.

[saladtossser]

engine manual
http://www.freewebtown.com/crazylilproj ... ine001.pdf
lol i scanned it

pics of engine
http://s35.photobucket.com/albums/d171/ ... er/gogogo/

[jrrdw]

Looks like a knok off of a Honda engine, the set up is normanly used on portable aircompressors. Very relieable, and esy starting, good choice. What clutch did you decide on?

[saladtossser]

the engine is actually meant for champion brand generators, it advertises that is it an "universal" engine

for a clutch i'm looking for something cheap and basic, 3/4" bore with 3/16" keyway and 12 teeth #35 sprocket

if i cant find it locally, i'll get it here
http://www.mfgsupply.com/m/c/4-455.html
cheaper

i'm a little short on cash, had to use some for a business class sale...

i managed to remove the key that came with the engine with a screw driver and a hammer...

is #35 chain the same size as a bike chain? and what does 35 mean? width?

[jrrdw]

No, not the same as a bike chain. The size (35) is overall size, the pins, pitch, lenth, width, not really interchangeable, you can get 35.2, 35.5, 40, 420, 40.5, all inbetween, under to really small to 2+"s. You can allso get half links, i get mine from True Value hardware store. Check out my thread on- go-cart with BALLS!!! We went with a 480 on it. The 225 CC engine has enough tork to break 2 chains allready, and we spun the center out of the right rear wheel/rim. So it's temporary down for the count rite now.

QUESTIONS-What size sprokets did you find to use? Real go-cart one's? Off of rideing mowers??? Manco go-carts call for a 420 chain, we used a 480 to fit the counter sprocket on the engine better, the motor cycle had a 520 on it, thats pretty stanerd for things over 200 CC'S.

[WOW!!]

I can give you a list of parts you need for the whole thing. You want ball bearaings. Pillow blocks are good becasue the bolt right to the frame. For the clutch you should use a Tourque converter but centrifical clutches are fine. Try and go for disk brakes, band/scrub are O.K but there wera out and the disk's give more stooping power. You want metal hubs, metal wheel and rubber tires, i like to have bigger tires in the back and smaller in the front. Make sure when you weld on your spindles that they are around *10. Becasseu you dont want to have to much toe, and... i forget hte other words for it. WHen you go to weld it all up tack everything together first and then weld it all up so this way if you have to go back and fix something it is easyer.

When you go to put the engine, make sure that it is allined with the axle and spricket, weld the axel first so it is easyer to allign everything up. For chain go woth #35 it is good all a round chain. I have to go ill repost later.

Josh

[saladtossser]

ok i understand the chain thing now

what ever sprocket from 39 teeth to 84 teeth (round it to the nearest if you want) will be fine depending on the wheel size i choose
since the cart will have one wheel, the sprocket will not be attached to the axle, simply bolted to the wheel, the wheel will either have a bearing right in it, or is on a very short axle

scrub brakes should be ok, i might consider making my own band and use a smaller solid rubber tire wheel for a drum
what the hell is "toe"?
how much slack should the chain have? if any?

out of cash for now... waiting for the business class money back + $30 for next weeks lunch... should be enough for a clutch

is a stick for throttle and brake at once ok?
i want the brake to engage when the throttle is low and disengage as soon as the clutch spins

oh and the engine has a on/off switch on it, and two wires that have one of those flat connectors, how do i attach a kill switch? what amp and volt rating should my wire and switch have?

[jrrdw]

Toe is when the front tire is turning in or out while you are looking at it from the front to the back. The best handling when your toe is dead center, parrell to the frame rails. Any amount of toe will create drag/push to 1 side or the other, also will slow you down, (don't wan't that).

A single stick for both throttle and brake will work fine, make it so you push to give gas and pull to brake. SAFTY REASON FOR PULLING TO BRAKE-It's allways easier to pull then to push, you will have stronger brakeing power to pull it.

If the switch can be removed from the engine, just extend the wires to where you remount the switch.

Wire is measurered by gage size, the smaller the number the heaver/thicker/the more strands the wire will be. For what your doing with the kill switch 16 or 14 gage will work fine-TECH TIP: The longer the wire, the heaver/thicker/more strands it has to be, don't use smaller then 16 gage. The flat connecters are really just quick disconnects so you don't have to cut the wires when removeing the flywheel cover to work on the engine, you can get male/female quicke connectors cheeply just about any auto parts store/walmart/hardware store/radioshack, they are just about everwhere. Or save the 5 dollars and cut and splice the wires to do what you need. Normanly i charge $1.00 a question- http://home.att.net/~j.weber/wsb/html/v ... html-.html but since your a fellow spudfiles member i don't mind helping you out, besides i like being on a winners side/or helping a side to win, know what i mean?

If you haven't seen it yet, check out this little silent video of the go-cart i helped built, we named it the PASTURE BLASTER http://s82.photobucket.com/albums/j246/ ... udfile.flv

[WOW!!]

I would use pedles instead of levers so both hands can be on the wheel. http://www.bmikarts.com They have good gokart parts. For more tourque/harder lanches go with a 12 tooth clutch and a 72 tooth down on the axel. For more top end speed go woth a 11 tooth on the clutch and a 64 tooth on the axel.

Dont go with scrub, put on band brakes they are better. Depending on how much money you have i would go with the dosk brakes. You should have to much slack in the chain, to much and the chain can come off and to little the compontents can become miss alligned. You should have enought so you can move it up and down a lttle bit.

You dont need the brake to be ingadged when you start the engine, that is waht the clutch is for, to stall the engine out. Where the kill switch is on the engine splice into one of the wires so that you have 2 switchs, 1 on the engine and in right in the sterring wheel of some were that is close to you.

O and jrrdw do you know anything about hydraulics? Because i have a John Deere SRX75 that i took the engine off of and put a 5hp B@S on it and iam putting a hydraulic sytem for the drive system. O and it has a 13in lift on it

If ya got any more questions just ask.

Josh