Viper Off Road Build

[mysteryboy28]

for a light kart and light driver it may be ok. but if you've got any real weight on the kart, and you're hitting some good bumps, things are gonna get screwy pretty quick!

 

[exenos]

Its not ideal I agree but I dont see any issue with it. Quad bikes done seem to have any handling issues related to having a monoshock rear.

 

[OzFab]

I'm more concerned that the big, heavy engine is sitting behind the axle, that may cause handling issues; that combined with the massive wheelbase & your steering is gonna be a bee-arch

 

[gjpgonzo]

I'm more concerned that the big, heavy engine is sitting behind the axle, that may cause handling issues; that combined with the massive wheelbase & your steering is gonna be a bee-arch

Yes I tend to agree. We just sat the motor anywhere for the pic, it was not in its final position, but I do agree that there may be a seesaw affect, what would you suggest….move the axle under the motor after the motor Is in its final position???

 

[OzFab]

IIWM, for starters, I'd move the shocks & put the engine where the shocks are; where it is right now, the kart will be heavy on one side; you can get away with it with a smaller engine but, the big engine will make a big difference. Then move the axle accordingly...

 

[gjpgonzo]

That would work very well. You may want to put a vertical support as well but I dont think you will need it because the upper arm wont be taking much if any vertical force, mainly horizontal.

How does this look?

 

[gjpgonzo]

Steering

How long should the steering (Spindle) arms be? How long should the Pitman arm be, and how do you properly locate it on the steering shaft?

 

[gjpgonzo]

How long should the steering (Spindle) arms be? How long should the Pitman arm be, and how do you properly locate it on the steering shaft?

Any one out there

 

[gjpgonzo]

IIWM, for starters, I'd move the shocks & put the engine where the shocks are; where it is right now, the kart will be heavy on one side; you can get away with it with a smaller engine but, the big engine will make a big difference. Then move the axle accordingly...

Progress Pictures, just waiting for the TC to come in for the motor.

 

[gjpgonzo]

IIWM, for starters, I'd move the shocks & put the engine where the shocks are; where it is right now, the kart will be heavy on one side; you can get away with it with a smaller engine but, the big engine will make a big difference. Then move the axle accordingly...

more pics

 

[mysteryboy28]

i think we are all just enjoying watching your build.

 

[OzFab]

I don't wanna say this but I have to: If you're thinking what I think you're thinking, it's not the best idea; placing the engine where that plate is will put the bulk of the engine weight behind the axle which can &, most likely, will cause handling issues because the front will be too light, similar to that of the early Porsche 911s...

 

[KartFab]

Wheelies bwaaaa!!!!!

 

[gjpgonzo]

I don't wanna say this but I have to: If you're thinking what I think you're thinking, it's not the best idea; placing the engine where that plate is will put the bulk of the engine weight behind the axle which can &, most likely, will cause handling issues because the front will be too light, similar to that of the early Porsche 911s...

Very good point and thank you for mentioning it. Here is my latest dilemma. The engine is big, (predator 420cc 13hp), and a GTC T2 1004 Torque Converter (#40/#41). I was thinking of placing the motor in the middle of the rear deck for weight distribution but….. with the center of the axle being 7 ¾” off the ground and a 60t sprocket that has a 9 7/8” diameter that will only give me close to 3” of ground clearance. So I am rethinking the plan to move the engine to the middle and place it closer to the wheel to help protect the sprocket.

Also…. The torque Converter has a 10t sprocket and 60t on the axle so my ratio will be 6:1

So to sum it up…..
15” tires
13 hp motor idle RPM is 1800 +- 50
6:1 ratio
GTC T2 1004 Torque Converter
….any idea how fast I can go in this puppy? Any idea what kind of off road performance I will be getting?

 

[mysteryboy28]

Google kart speed calculator. You should easily find the one that is on this site. At 6:1 ratio and 15" tires, you should have gobs of off-road torque. I've got a 6:1 ratio with 20" tires and 13hp motor and its pretty quick with my fat a$$ on it. you could probably get away with a 54t axle sprocket and still be fine with torque.

Faster is not always better than quicker. Torque rules when off-roading!

 

[gjpgonzo]

Google kart speed calculator. You should easily find the one that is on this site. At 6:1 ratio and 15" tires, you should have gobs of off-road torque. I've got a 6:1 ratio with 20" tires and 13hp motor and its pretty quick with my fat a$$ on it. you could probably get away with a 54t axle sprocket and still be fine with torque.

Faster is not always better than quicker. Torque rules when off-roading!

What brand of motor do you have, I can't find the top RPM for mine.

 

[mysteryboy28]

all the industrial motors run about 3600 top RPM, unless you tinker with the governor (which you shouldn't do without some good research to be aware of the safety concerns).

 

[gjpgonzo]

all the industrial motors run about 3600 top RPM, unless you tinker with the governor (which you shouldn't do without some good research to be aware of the safety concerns).

Then it looks like 27 mph really that's it?!?!?!

 

[landuse]

Then it looks like 27 mph really that's it?!?!?!

How fast do you want to go? You might have to play around with the engine a bit for more power

 

[exenos]

Do you already have that torque converter? If you haven't bought it yet you may want to look into a 40 series instead of a 30.