My gokart

[daniel7250]

Hey guys.
Picked this up for free.
Mods i've done are: Custom exhaust, New intake, and hydraulic disc brakes. Only problem with the brakes are they dont work . so its abit scary. knocked my front fence clean over .
Mods to come: removal of the Governor, New steering linkage.
Specs: 5hp Mitsubishi Engine, top speed bout 30km/h

 

[Doc Sprocket]

Cool little kart. Why do the brakes not work? A hydro/disc setup should lock the axle up solid, no questions asked. So, what happened?

 

[daniel7250]

well im thinking they have air in them but also there is abit of fluid around the frame so they could be leaking ? . im not overly sure .

 

[honda-gx-power]

Would be better if it had one chain just from clutch to rear sprocket.(i no they not lined up)
What engine is that?And get a new one of them brake cylinders from a pit bike or off ebay for cheap.Good idea that what someone as done there.Im going to do same thing on mine when i get to the brakes part of project.Could do with getting rid of them back wheels as they will be very heavy.Good little cart tho.

 

[Doc Sprocket]

When you installed the brakes, did you bleed the system?

 

[devino246]

well im thinking they have air in them but also there is abit of fluid around the frame so they could be leaking ? . im not overly sure .

I wouldnt suggest driving until you've fixed them. Air in the lines could be caused my loose connections, so go over all the connections and make sure they're good and tight. All you need to do to bleed the brakes is make sure the reservoir is full, then open the bleeder screw on the caliper. Let it drip for a little while then close the bleeder screw. DO NOT pump the brake with the bleeder screw open, you'll just suck air into the system.

 

[devino246]

Would be better if it had one chain just from clutch to rear sprocket.(i no they not lined up)
What engine is that?And get a new one of them brake cylinders from a pit bike or off ebay for cheap.Good idea that what someone as done there.Im going to do same thing on mine when i get to the brakes part of project.Could do with getting rid of them back wheels as they will be very heavy.Good little cart tho.

He has the jackshaft to lower the gear ratio without having a horribly gigantic axle sprocket.

Specs: 5hp Mitsubishi Engine, top speed bout 30km/h

 

[honda-gx-power]

Top speed of 30km/h. whats that in mph as i dont understand km/h. Is it around 12mph?
If so i would of thought it would of done 30mph with a 5hp mitsy engine.Them engines are rare in uk and are builtproof.You want to try make it go faster than that.I would aim for 30mph at least.But you need brakes then,Cant crummble for nothing tho, even if you spend $100 on it, it will look better and you will always get back what it stands you at and a bit more maybe.Are you going to spay it?Spray it red,

 

[daniel7250]

yeah im working on how to remove that business at the back. ill take a pic of my brake set up and show you guys . ill upload in 10 . also i need to rebuild the brake pedal and setup. you can see in the first pic . any ideas ?

 

[daniel7250]

im getting a bucket seat from a rally car to put in it and im not sure what color to spray it . red sounds good tho
here's the break setup

 

[Doc Sprocket]

Let's start with the parts- what are the master cylinder and caliper from, and what kind of condition are they in?

Re: bleeding the brakes- sometimes the above-mentioned gravity-bleed method does not work well. It's okay if the pedal is rock-hard, and nothing but. Here's the harder (but 100% effective method:

1)Put a length of clear tubing on the bleeder screw, and into a clear jar, to the bottom of the jar.
2)Put some brake fluid in the jar, to cover the end of the tube well
3)Remove the master cylinder cover, and top up the fluid
4)Loosen the bleeder screw 1/2 turn
5)Press and HOLD brake pedal
6)finger tighten the bleeder screw
7)Release brake pedal
8)Repeat steps 4-7 until NO air bubbles appear in tube or jar. Remember to keep fluid level high in master cylinder
9)When bubbles no longer appear, wrench-tighten bleeder screw, and test pedal for firmness. If not firm, re-bleed. If still no joy, you may have a bad piston seal, scored bore, ot other internal problems.

NOTE- sometimes the above process is easier with two people. Have the guy operating the bleeder screw instructing the pedal guy when to push and when to release. Remember NOT to let the pedal up with the bleeder screw open.

 

[Doc Sprocket]

I suggest replacing that threaded rod with actual graded bolts. Let me see the pedal and master cylinder setup, please.

On second thought, see if you can move the rotor closer to the framerail, and get rid of the extra plate and bolt length.

 

[daniel7250]

yeah iv tried the gravity feed but i think it still had air in the tube. i also tried force bleeding from the bottom that work alot better but still spongy . i dont have 2 people to try the second method . all my mates are away on holiday atm .

 

[daniel7250]

the brakes are off the front of a pit bike. that second plate is there to hold the caliper so it doesn't spin because only 1 bolt would go in with the caliper on the disk . ill upload pic in ten

 

[Doc Sprocket]

I'm not sure what you mean by force-bleeding from the bottom. If you mean trying to blow fluid in thru the bleeder, that probably won't work well, especially if there's a check valve in the master cylinder.

 

[Doc Sprocket]

That caliper only has ONE mounting hole? WTF?

 

[daniel7250]

No ,no . it is like a normal caliper with 2 mounting holes, but if both of them were mouted on the same bracket on the frame only about a quater of the break pad made contact with the disk. so i made that plate to fit on properly. here is a pic of the master cylinder .

 

[Doc Sprocket]

If you can weld, I strongly suggest re-doing that. There will be some pretty impressive shear loads on thoe long, ungraded threaded rods.

What I can't see is exactly how the pedal acts upon the master cylinder.
Is that master held in place only by the handle pivot bolt?

 

[daniel7250]

i need to make a new pedal and what not. cos the one on is poor and bent. any suggestions for that ? i was going to put a piece of RHS on the other side of the bolts and maybe another plate, do you think that would do ? Yes 1 bolt but thats only temp till i work out how else to mount it. iv only had this kart for about a week and in between chemo, rain and blistering heat its hard to work on. stupid tassie weather :/ . todays looking alright tho

 

[honda-gx-power]

Mad that dont look strong as the metal crap and weak that the screw is in on that cylinder.There should be 2 holes and theres only 1 and thats the 1 the screws going in.Get rid and get a new cylinder off a pit an keep brake lever on it and link your brake pedal to brake lever on the cylinder so that when you press you brake pedal it pushes the brake lever in.Weld little piece of handle bar to kart to apply the new pit brake cylinder with the brake lever still on it.