racing gokart build

[qj8f]

hey guys im planing to build a racing go kart and need all the help i can get i have a old a-frame go kart roller and i was planing to put a Suzuki 650cc motorcycle engine on it cuz theres a store by my house that sells 650s for 600 bucks you get the whole wrecked bike minus the forks swing arm and wheels the engine is going to be a four cylinder but in unsure if i want liquid cooled or air cooled cuz i plan to bring this to a drag strip so give me ur opinions liquid cooled or air cooled

all help is needed

 

[ipwnr]

air-cooled is the way to go because liquid-cooled is heavier then air cooled and theres less parts on a air-cooled engine to fail like coolant pump etc. IMO

 

[fowler]

what model are u after
the ealy air cooled engines may me lighter but they have alot less power
also air cooled engines only work if u can keep a high speed (u wont)

i dont know if suzuki make newer air cooled engines in that size

putting a 650 on a kart will make a tyre eater
if u use a 250 u will get the same speed as a 650

u wont be able to get power to the ground
u really want a junior dragster if u only wanna drag
or a mini buggy if u want other uses
more weight = better power transfer
bigger size = more stable at speed

u may have seen these things on youtube but dont forget only 1 in 20 are any good and that requires alot of money and skill

 

[qj8f]

but how would a 250 give me the same speed?

 

[redsox985]

They probably have close gearbox ratios as well as similar red lines. The only major thing that differs is that the 600 has more grunt on the low end. It may take longer to get up to speed, but it may not. With as little surface area as kart tires have on the road, that 600 may be too much power and the tires will smoke and not transfer the power whereas a 250 would put less power into them, but they would make stronger contact and grip instead of just spin and smoke.

 

[qj8f]

but is there anything a little higher cc than 250 with Suzuki

 

[machinist@large]

but is there anything a little higher cc than 250 with Suzuki

Yes; Suzuki,Honda,Yamaha all made air cooled bikes as big as 1000 cc or more. Some of them still have air cooled bikes in their new line up's.

 

[fowler]

if u want power to weight then get a 250cc two stroke dirt bike engine

iv the honda's in action on a bike that weighs more than a kart

u will wheelie that kart and it has power to weight nothing can match

 

[qj8f]

ya but i have no way of getting my hand on one but the bike shop by my house sells wrecked motercycles like sport bikes and stuff not dirtbikes

 

[fowler]

well thatll still work
but u not need 600cc

as for air cooled bikes
yes they are simpler
yes they are lighter
yes they are asyer to set up

but in my experiance they dont go so well on karts

the 250cc honda cm i have gets very hot
dont forget these engines are use to 50mph winds without restriction u wont keep that speed
dont forget the police changed to water cooled bikes because they were better in traffic (poting around at low speeds)

if u get an air ccoled bike make sure it has an oil cooler and is mounted on the side not behind the seat

 

[lewikenzie1]

You dont want to go as high as 600cc thats just a waste of petrol, youll never need that much power, go for a 250 or 350cc watercooled bike, ive just put a gx 390 in my little kart and fs it shifts, takes a couple of seconds for the centrifugal clucth to kick in then its like NOS haha, youll never even find somewhere to get the use out of something with that amount of power.

 

[fowler]

and a gx 390 is only 13hp a 250 bike engine is more like 22

 

[the-cyborg]

and a gx 390 is only 13hp a 250 bike engine is more like 22

Horse power is one thing, RPM's, torque, and gearing is another.
I have a cart with a subaru 13.5hp (404cc)
and another cart with a kt125 which would equate to roughly 5hp.
Now true the 13.5hp has raw low end torque hell I could pull stumps with it, the problem is even with the governor pulled the best I can hope for is 5k-5.5k rpm's maybe 6k if I lucky, combined that with with with power lost to friction, stroke and weight of the engine you only going to get so much top end out of it. don't get me wrong it is a bad a$$ powerful cart, but not for speed. top speed I've got out of it is 52mph
Now the cart with the kt125 can easly turn 7k-10k rpm without breaking a sweat and will easily reach 70mph, why?
lighter, shorter quicker stroke much less friction loss.
True they er on two totally different chassis, but even if I were to shoehorn the 13.5hp on the race cart chassis there is still no way it would ever achieve the performance of the kt125.
That being said I have made shifter carts with old air cooled 2 strokes and they work wonderfully, irregardless to what anyone else tells you on here you are not going to over heat engine to where it will do damage, I recommend you find you a 100cc to maybe 250cc 2 stroke bike engine and you'll find that you will achieve what your looking for,2 stroke engines are made for high rev, high performance under varying conditions.
What you have to keep in mind is power to weight ratio, you can have too much engine that is too heavy that will actually become counter productive and you will actually loose performance.
Then you have gear ratio, with an industrial 4 stroke engine setup you have a fixed gear ratio, that will either net you good low end torque or good high end speed, but rarely both either you'll put the engine and clutch under a strain in low end to achieve top end speed, or you'll have great low end torque but sacrifice speed.
with a 4 or 5 speed motorcycle gear box you'll have the best of both worlds because the gear ratio can be varied to the load and conditions while keeping the rpm's up.

 

[the-cyborg]

BTW a 250cc bike engine will be closer to about 8-9 hp not 22hp
a 20hp engine would equate to roughly 625-630cc there about .

*Edit a honda gx240 is a 8hp engine, you do the math.

 

[anderkart]

What... most 2-cycle/250cc motocross engines made in the last 10 years have around 60hp: http://www.motorbikes.be/en/Honda_CR_250_R_2003.aspx

 

[qj8f]

so should i get a 300cc and call it even but if i get the 300 wat should i get with it water cooled cuz its heavyer or air cooled with an oil cooler

 

[Rustydog2010]

BTW a 250cc bike engine will be closer to about 8-9 hp not 22hp
a 20hp engine would equate to roughly 625-630cc there about .

*Edit a honda gx240 is a 8hp engine, you do the math.

That maybe true for industrial engines. I have a GPZ750, and by your logic that would be what? 22-25 hp? It is rated at over 90hp.

@OP, you want the largest 2 stroke air cooled engine you can find. With the right gearing that will smoke a 650. I also have a DT400 which is a 2 stroke 5 speed dirt bike engine rated at about 30hp. That thing goes and would be lethal on a light shifter frame.

 

[the-cyborg]

What... most 2-cycle/250cc motocross engines made in the last 10 years have around 60hp: http://www.motorbikes.be/en/Honda_CR_250_R_2003.aspx

1 cubic inch ( cu.in. ) = 16.387064 cubic centimetres ( cu.cm. cm3 or cc )
1000 cc = 1 liter
1 hp (UK) = 0.7457 kilowatt ( kW )
rpm = revolutions per minute
15 to 17cc = 1 hp or about 1 cu.in. = 1 bhp for a modern car.
lets do the math
250cc/15=16.66hp or 12.428 kW
250cc/17=14.7hp or 10.966 kW
1000cc / 250cc= 4 or .4 liter
but these equations are flawed were missing key info

how do you get 250cc= 60hp
key pieces of info in the equation we are missing is rpm's and torque.
Horsepower = (torque * rpm) / 5252
so therefore on that cr250
hp= (37.6*8000) /5252
hp= 57.27hp @ 8k rpm
but drop the rpm down to say 3600 rpm (typical stock industrial engine) which is going to effect the torque foot pounds
Now lets use the specs of a briggs 1150 series engine rated at 250cc
hp=(11.5*3600) /5252
hp= 7.88
as you can see rpm is relative to torque is relative to hp
therefore if we could get that briggs to stay together at 8k
rpm perhaps we could get 57 hp out of it, and conversely that cr250 at 3600rpm will equate to approximately 8hp prove me wrong.
so a 250cc could in theory be any any hp it just depends on the torque at a given rpm.

In reality there is no formula that exist to convert cc (cubic centimeters) to Hp you can convert cc to ci (cubic inch) but that has little to no bearing on horse power, these are measurements of area or distance
Horsepower is the relationship of torque at a given rpm divided by 5252.

 

[sexyvicta]

BTW a 250cc bike engine will be closer to about 8-9 hp not 22hp
a 20hp engine would equate to roughly 625-630cc there about .

*Edit a honda gx240 is a 8hp engine, you do the math.

bull****

get an rs250 and you'll have 70hp.

the capacity of the engine is not the only factor involved in making horsepowerZ

 

[fowler]

there is no connection between ccs and hp

just type cc to hp convertion

i asked that when a first jioned hopeing to get a very rough conversion formula

and well u can read the results

dont forget the qualitly of the engines have a big part to play

the bike engines will run finer tolerances sure as windage as this lets less power escape but causes more wear and would last that long, but who care u only run it on weekend or maybe drive it to work on nice days

an industrial engine needs to run 24/7 for its whole life and if its a water pump or part of a machine it doesnt matter u cant afford to have it fail so the tolerances are larger and it lasts longer but some power escapes
they counteract this by makeing the engines large displacement so they have pllenty of touque


ask yourself this
an f1 car has a 2.8L v8 that makes 980 hp (wiki fact)

an 05 mustang GT has a 4.6 L V8 that produced 300 hp (wiki fact)

now tolerances aint the only factor but it is a big one among many others