60mph goal, horsepower and gearing questions.

[ChattaBrony]

So my lovely friends i have decided to embark on a project. I own a substantial amount of land in North Cariolina (in the Hiwassee dam area, if anyone is close maybe we could hang out?) and i know for the frame i am going to build something with decent ground clearance, for the sake of utility, and of course suspension. The trails are fairly smooth but I think suspension would help the ride. Now the thing is on those mostly unused roads in the area i would like to be able to get in the 50mph territory. what horsepower would i need to be able to get that fast with good acceleration? I have a 20 horsepower engine that I can convert to horizontal shaft, and then use a comet 40 series CVT (would that be okay for this size engine? im open to ideas), but i've also seen 18hp horizontal shaft hondas floating around on craigslist. is this goal achievable or do i need significantly more horsepower in order to have good acceleration?

 

[OzFab]

A high top speed is all in the gearing; as you mentioned ground clearance, let's assume you'll be rolling on large tyres, say, around 20". To achieve 50mph you'll need 7:1 gearing with the engine revving at 6000rpm, not impossible but, not cheap either...

The better option is a motorbike or snowmobile engine but, since you're in NC, I think they might be a bit rare so, lets stick to a bike engine. With multiple gears, you get the best of both worlds, low gear for acceleration & a massive top speed...

Having said all that, I hope you have teriffic welding, engineering & fabrication skills because, if anything goes wrong at that speed, more than likely, it won't mean a trip to the hospital, it'll mean a trip to the morgue!

 

[Half-breeder]

NC here too... what size wheels you wanting to run?

Plz fill out your profile plz.

 

[mckutzy]

I saw this earlier this morning. I didnt really know how to respond. It kinda is outside the realm of our little world here. Our machines here dont typically go that fast, and for good reason.

 

[firemanjim]

You're gonna WANT a dirt bike engine around 125cc to 200cc. That will be more than plenty to get you through the muck and then on the open road, you can quickly get up to 50+ mph..... You can buy a new Lifan engine on ebay for $200-400 depending on what size you get.....

 

[ChattaBrony]

Having said all that, I hope you have teriffic welding, engineering & fabrication skills because, if anything goes wrong at that speed, more than likely, it won't mean a trip to the hospital, it'll mean a trip to the morgue!

i am fairly confident in my fabrication skills, thank you for the concern i initially thought a gearbox would be best, i just dont like the idea of butchering it out of some used vehicle, i would like to spend the money to make something new that will last. any ideas for the gearbox?

 

[ChattaBrony]

NC here too... what size wheels you wanting to run?

Plz fill out your profile plz.

Profile is filled out now I have no idea what wheels i will use

 

[firemanjim]

Buy a new Lifan dirt bike engine off ebay. It has built in gearbox with either a 4spd with/reverse, 4spd, and 5spd, depending what size you want. That's the only way you will get 50 mph on a big kart/buggy/utv....
I'm fixing to order a Lifan with reverse, for a special future (up coming) build. Decent engine, good power, good longevity...... It'll make a yard kart and racer with the quickness.... I know first hand, a 90cc 4 spd will make you grin and cry at the same time.....

 

[Half-breeder]

Wheel size will also determine you top speed, is why I ask...

I run a gx200(pushin close to 11hp now), no governor, n 30 series TC(TAV2), on 16" wheels... Im geared at 5:1... I do 50-57 mph(aint opened it up...yet. Just rebuild motor yesturday)... n boy does she fly!

 

[KartFab]

I can't do the math now, but yes you can get 50-60 mph on a larger kart/mini buggy, even with an automatic trans.

I'll throw in another perspective:

Briggs vanguard 35 hp with comet 94c duster clutch and 94D driven unit. The v-twins are pretty nice and reliable honda gx620 and up, kohler.

Then you won't have to worry about shifting.

 

[ChattaBrony]

Buy a new Lifan dirt bike engine off ebay. It has built in gearbox with either a 4spd with/reverse, 4spd, and 5spd, depending what size you want. That's the only way you will get 50 mph on a big kart/buggy/utv....
I'm fixing to order a Lifan with reverse, for a special future (up coming) build. Decent engine, good power, good longevity...... It'll make a yard kart and racer with the quickness.... I know first hand, a 90cc 4 spd will make you grin and cry at the same time.....

yes!!!!!c this is literally perfect, and i found a rich friend that is willing to pay half can you recommend a good carb?

 

[Datsun]

If you end up with a 125-160cc lifan pit bike 4 speed have a look at this carb ~ http://www.dhz.com.au/buy/oko-28mm-flateslide-race-carby-kit/CARB-05-28-KIT


The first link is a good performance carb, the second link here :http://www.dhz.com.au/buy/mikuni-30mm-racing-carburetor-kit-140cc-150cc-160cc/CARB-002

It's a great carby, but isn't a high performance one like the first link, but they still work great.

You can buy them on ebay, but that will give you an idea of what you're looking for.

Also if you end up with something 125 or smaller I suggest you use a smaller carb, 19mm-26mm etc.

 

[will221sd]

A beetle any body

hey maybe you can get an old bug and strip it (maybe shorten it) and add a roll cage. stiffen and lower suspension for less body roll