8 hour off road go kart

[SGTTARD]

hey guys im new to DIY, also here is my off road Kart that i built in 8 hours. it kinda looks like a hack job but i dont care cuz its fast and fun. about the kart, it has a 300cc rotax 2stroke 18hp engine, turf tires all around. im using a jerry can for a fuel tank which works great if i run out fuel and have to walk. the most of the Kart is made from ski-doo parts so i guess the brand would be BRP, no name yet. it has clutches from an old 1970 ski doo oly, and the seat is out of my 1986 mustang. anyways here are some pics, if they work.

 

[mysteryboy28]

a (good) video of it in action would be cool!

 

[OzFab]

It does look like a bit of a "hack job" but, what do you expect from an 8 hour build.

In saying that, you've done well; as long as everything's in the right place & it works... you can always tweak it later.

I spent 6 months on a build & I'm still tweaking it

 

[SGTTARD]

soon i will get a video once it stops pouring here, been raining for a week now. right after it was done we went quading for 3 hours and about 60 miles. it ran perfect. but your right there is some stuff i want to change. like adding rear suspension and more roll bars for protection. i also have a 440f/c rotax engine that i want to install in it. i will keep adding as time goes on i guess.

 

[landuse]

Thats is brilliant build for the time that you spent on it. I wouldn't even have gotten the front suspension sorted out in that time

 

[SGTTARD]

i cheated and used the dimensions of a honda odyssey, except for the j-arms they would of taken too long to make so i just used an old ski doo's front suspension.

 

[SGTTARD]

i decided to tear down my buggy and redo the drive train. i am gonna swap my 300cc rotax for a 13-15 hp 4stroke utility engine. i am also getting rid of the torque converter set up and going for a chain drive centrifugal clutch with jack shaft. but i am not sure how to calculate my gear ratios for decent performance. my tire dia. is 16.5" and the axle sprocket i may use is a 52 tooth. now i just need to know what other size sprockets i need. can someone please help? thanks

 

[souperman000]

Why do you want to ditch the TC?

 

[mysteryboy28]

going from a sled engine with a TC to a utility engine with a centrifugal clutch will REALLY disappoint you! why would you do this??? sled engines rule!

tired of premixing? that's the only thing i can think... it's worth it for the power and RPMs!

 

[SGTTARD]

well im not 100% sure if i wanna get rid of the tc, i guess im tired of the clutches getting dirty and sticking all the time. want to make the drive system simple and less maintenance. reason for the engine swap is because the rotax is loud and has to stay in high rpms to make torque. i like to trail ride so having a quiet low rpm high torque engine fits my driving style. plus my niece likes to drive it and right now its way too fast for her.

 

[Amped]

Keep the sled engine and add a quieter exhaust and a tranny. That way it will be more versatile . You could make a pedal stop for when the kids ride.

 

[B man]

Keep the sled engine and add a quieter exhaust and a tranny. That way it will be more versatile . You could make a pedal stop for when the kids ride.

problem is the sled engine HAS to have that exhaust to run properly.

 

[exenos]

Eh, if you look closely its just a can. There's no expansion chamber on the engine and it came stock like that. If he just put a car muffler right after the stock one it would run just like it is now except a bit more quiet.

2 strokes do not need a expansion chamber to run properly. A engine that was set up to run with a chamber will run poorly with just a can or straight pipe untill rejected properly. All a expansion chamber does is shove escaping fuel are mix back into the cylinder, adding a bit to the power. The engine will operate fine without that extra fuel air mix, it will just do so at a reduced power output.

 

[landuse]

You are going to have to gear REAL low if you want to use a centrifugal clutch with 16" tyres. That means that you will prebably need a jackshaft, because you are never going to get an axle sprocket big enough to give you the reduction you will be happy with. You are going to have to gear to at least 8:1 with your kart

 

[Nodroz]

You are going to have to gear REAL low if you want to use a centrifugal clutch with 16" tyres. That means that you will prebably need a jackshaft, because you are never going to get an axle sprocket big enough to give you the reduction you will be happy with. You are going to have to gear to at least 8:1 with your kart

Don't forget it's 2stroke, they go higher in rpm and therefor I think he should get somehting like 9:1 or 10:1.

Would that make more sense?

EDIT: Oh wait. Ignore... I just read he's going to replace it with a industrial 4stroke engine. Disregard...

 

[Doc Sprocket]

Do keep in mind that even a centrifugal clutch is not immune to the elements. Instead of getting rid of your CVT and flushing and hope of performance down the latrine, maybe look at a creative way of keeping the crap out of it.

 

[SGTTARD]

well the 4stroke is for sure going in, they are just plain reliable. i dont have to tune for the weather conditions, and they are a throw away engine. prices for them are very low these days. you guys are right about the tc i think it will stay. now i just need to find a primary clutch that fits the engine and matches my belts and driven clutch.

 

[exenos]

Good luck with that, they don't show up on ebay often, even then expect to be paying upwards of $300 for one. You'd be better of to grab a mid sized bike engine.

 

[Amped]

well the 4stroke is for sure going in, they are just plain reliable. i dont have to tune for the weather conditions, and they are a throw away engine. prices for them are very low these days. you guys are right about the tc i think it will stay. now i just need to find a primary clutch that fits the engine and matches my belts and driven clutch.

I have some used CVT sets I might part with for cheap . What are your bore sizes ? OH and what country are you in? Are going to sale the ROTAX? If so how much?

 

[SGTTARD]

i found a comet clutch, a friend brought one over and i think it will do. on the good side if im really unhappy, i can go back to the 2 stroke cuz not much will change. just the engines will be swapped. the older rotax's are getting hard to find, so no sorry none of my rotax engines are for sale. but i have a 1976 evinrude 440 engine for sale though.