spider box turned mini buggy

[gixxer kart]

i picked up this yerf dog rolling frame last summer for a hundred bucks. i was originally going to use a gsxr 750 motor on it but decided on a sled motor instead. power plant is a polaris indy xcr 600 sp liquid cooled triple cylinder rated at 116hp. i just finished up putting the axle together and mounting the engine. starting on the swing arm now. i bought a 2001 mojave quad rolling frame for the suspension, wheels, and tires. also using the hydraulic disc brakes and parking brake. but anyway, heres some pics at various stages. the kart is 5' wide and 9' long.


the day i bought it

 

[gixxer kart]

fitting the front suspension up

 

[gixxer kart]

welded up

 

[gixxer kart]

mocking motor up

 

[gixxer kart]

built a real frame under the cage tieing the front suspension, cage, and rear swing arm together

 

[gixxer kart]

took off the bolted on stock "cage" and put together a real one

 

[gixxer kart]

cage and engine support mostly finished up, motor mounted, and pipe fitment. now figuring out jack shafts and swing arm

 

[n1kogr]

looks good so far great work. But i would do independent rear suspension. It will be such a more enjoyable ride

 

[gixxer kart]

I thought about it but I think this will be more stable. Plus it didn't cost me anything to make it this way, IRS doesn't come cheap. Especially to hold up to 120hp

 

[gixxer kart]

Anyone with sled motor experience have any input on gearing? 22" tires

 

[souperman000]

Anyone with sled motor experience have any input on gearing? 22" tires

MysteryBoy28 might show up, or PM him. He builds his buggies with sled motors.

 

[mysteryboy28]

and here i am. lol.

i gear mine to almost 9:1 with 24-25" tires, using the stock gear box for initial reduction (29:17), then a 10t to 50t on the axle. that gives an approx top speed of around 60 mph and some good torque. with 22" tires you'll get a little more torque, and a little less top speed - which is a good thing for climbing hills and maybe popping some wheelies!

 

[gixxer kart]

Yea I'm shooting for around 60-70 top speed but I want plenty (as much as possible without sacrificing too much speed) of torque. I don't have the sled gear box but I'm planning two jack shafts to get the gearing down. Like a 13t to a 31t ish then a 13 to whatever I need on the axle. I'm using a #50/530 chain. I already have a 31t sprocket so I plan on using it somewhere in there. How do you figure out the ratio with the belt/clutch setup of the sled?

 

[gixxer kart]

Are you saying 9:1 not including the belt and pulleys, just assuming its around 1:1 final drive?

 

[mysteryboy28]

yup. the torque converter won't be EXACTLY 1:1, but close enough.

 

[gixxer kart]

Ok so 8:1 is giving me 69 mph with 22" tires. Probably going to shoot for that

 

[gixxer kart]

It will just be a starting point. Ill interchange the axle sprocket to fine tune it

 

[mysteryboy28]

i'd shoot for 60mph top speed. that'll guarantee you have awesome torque for amazing hill climbing ability. i mean seriously, where are you going to ride that thing going 70mph? when you're off-road, even 40mph feels fast! the extra torque will come in handy for making fun little jumps and whipping around corners just by tapping the gas.

 

[gixxer kart]

welded tabs on the rad for the shroud and fan, and got rad mounted to the cage.

 

[exenos]

Do you have any clutching experience?