Newbie Learning the Kart Ropes. Lots of Questions...HELP!?

H

higgypoo

Member
Messages
33
Reaction score
11
Functional Artist said:
Progress is lookin' good! :thumbsup:

A couple of observations, if I may ;)

It looks like the dash may be pretty far away from the driver.

It looks like the caliper could be mounted a little bit closer to the rotor.

The brake "rod" looks like it could be a little bit on the small side (maybe ~1/4"?)
...& it also, looks like that bend (just behind the pedal) may "straighten out" upon hard braking
Click to expand...
Thanks. Yeah the caliper could mount closer, but it wouldn't really be doing anything, the pads inside are completely on the rotor, so I think that's good for now. As for the dash,...yes, it kinda far away, I wish I had done the steering support later. I basically guessed where I thought it should go...oops. but the gadgets are still pretty easily in reach for me so thats good.
Good call on the braking rod. It is 1/4" ,but I thibk it'll be pleanty strong. I'll have to keep my eye on it to see if it straightens at all. For right now, I might have to rig up some odd little doohicky to get more lever action from the pedal...Haven't solved that one yet, so if anyone has any ideas...throw em my way please!! :)
 
H

higgypoo

Member
Messages
33
Reaction score
11
Ok, got the kart up and running and took her on her maiden voyage. Got to the end of the block and back before I had some issues. Id love some help on these if anyone has some suggestions.

1) the live rear axle doesn't allow the rear wheels to spin independently so turning was almost impossible.

2)after a very short run, the engine stopped spinning and touching the accelerator results in a small jerk and a loud buzzing sound from the motor. Did I burn it out with a 2 min drive?

3) initial acceleration is really jerky until I get up to about 10-15mph.

Any remedies for any of these would be a tremendous help
 
R

redflash

Well-known member
Messages
650
Reaction score
619
you've learned your first lesson, go kart quality electric motors cost $1000. Thats why I dumped electric and went 420 gas. Far less technology, and far less problems.
 
Functional Artist

Functional Artist

Well-known member
Messages
4,406
Reaction score
1,686
Location
Toledo, Ohio
1.) Yes, live axles are notoriously known for making it difficult to turn, especially at low speeds

2.) What does it do "unloaded" (with the rear wheels "up" off of the ground)?

3.) Are you still running the 11T drive sprocket (on the motor) & a 54T driven sprocket (on the axle)?

This would be a 4.9:1 gear ratio (54/11=4.9) which like EZ said in post #3) is a very high (or tall) GR
...& could overload a small motor (especially trying to "muscle" thru a slow turn, with a live axle)
 
H

higgypoo

Member
Messages
33
Reaction score
11
Functional Artist said:
1.) Yes, live axles are notoriously known for making it difficult to turn, especially at low speeds

2.) What does it do "unloaded" (with the rear wheels "up" off of the ground)?

3.) Are you still running the 11T drive sprocket (on the motor) & a 54T driven sprocket (on the axle)?

This would be a 4.9:1 gear ratio (54/11=4.9) which like EZ said in post #3) is a very high (or tall) GR
...& could overload a small motor (especially trying to "muscle" thru a slow turn, with a live axle)
Click to expand...
Ah, ok, just spent some time in the shop and figured out what the main issue is...this solves problems 1 and 2 if I can solve it.
It looks likenthe axle spocket I have isnt exactly circular...this each rotation creates severe tension and then slack on the chain...when trying to start in the state of tension, it can't move...but it does work when there is slack on the chain. SO I think im going to have to spring for a new sprocket set and chain. The set I have was frankenstined together with cheap Chinese parts.
As for the rear wheels, no solutionnyet unless I want to build a rear differential at some point.

The gear ratio is in fact still a 11:54. Which i figured would give me more torque, bu I suppose I could go for something closer to a 60 tooth. Is that what would be easier on the motor?
I think I might need to move my seat forward to get more weight on the front tires for better turning as well.
 
Functional Artist

Functional Artist

Well-known member
Messages
4,406
Reaction score
1,686
Location
Toledo, Ohio
higgypoo said:
The gear ratio is in fact still a 11:54. Which i figured would give me more torque, bu I suppose I could go for something closer to a 60 tooth. Is that what would be easier on the motor?
Click to expand...
Yes, a too high of a GR is kinda like trying to start off (in a gasser) in 2nd or 3rd gear :eek:

A lower GR will give you more torque (like 6:1 &/or 7:1 will give you even more) & be easier on the motor
...& a higher ratio will give you more speed (but, more stress & strain)

It's best to "try-n-find" the happy medium between the (2) :cheers2:
 
nobled2

nobled2

Member
Messages
32
Reaction score
36
Functional Artist said:
Well, for test purposes, try removing the axle "key" from (1) of your rear wheels (& maybe smear a little grease on the axle)
...then, take it for a test ride
Click to expand...
or just use a trailer hub on one end of the axle....

I am the sponsor of a club in a high school for a solar powered go kart, electric go kart charged by solar panels. Someone else had done this years ago and we inherited the old kart. everything worked once we got it wired back up and we ran in to same problem with rear axle binding up whole thing when turning.

Replaced one axle hub with trailer hub secured by shaft collars and it worked great
 
H

higgypoo

Member
Messages
33
Reaction score
11
nobled2 said:
or just use a trailer hub on one end of the axle....

I am the sponsor of a club in a high school for a solar powered go kart, electric go kart charged by solar panels. Someone else had done this years ago and we inherited the old kart. everything worked once we got it wired back up and we ran in to same problem with rear axle binding up whole thing when turning.

Replaced one axle hub with trailer hub secured by shaft collars and it worked great
Click to expand...
oh yeah, nice. I hadn't seen this before, a trailer hub looks perfect! I'm going to give the live axle a shot for a week or so, and if its still giving me trouble, i'm going to order one of these. great suggestion. thanks. I'll just have to figure out a way to attach the wheel since its a live axle wheel without any anchoring holes.
Thats awesome that you're doing that with the highschool, solar panels are a great idea for something like this.

***Update: Ordered new axle and motor sprockets, i'll be going with a 9/60 tooth set up (6.66 ratio). Now to get these brakes to work better
 
H

higgypoo

Member
Messages
33
Reaction score
11
Hey, does anyone know how to figure out what a low voltage level for a battery is?
I've got a LiFEpo4 72v 42ah battery and I just want to make sure I don't overdischarge. I have a BMS on it, but I want to just keep an eye on things myself as well.
 
H

higgypoo

Member
Messages
33
Reaction score
11
After exchanging the sprockets and chain im still running into the same issue of the motor binding and seizing. Finally I removed the entire brake caliper and what do you know...works like a charm now. So evidently the disc and caliper were binding the rear axle. I can't seem to figure out what is causing this since the axle spun freely when the brakes were attached. So either need an alternative braking system or a way to get this mechanical brake to work properly
 
You must log in or register to reply here.
Top