Newbie just bought a Kart with potential

[perceptionist]

Hey all,

My most recent purchase on Friday 7-11-08 happens to be what led me to these forums.

It is a homemade go kart with a 600cc motorcycle engine from a Kawasaki GPZ Ninja.

I have always wanted to build one of these. The engine runs fine but could use some TLC. I cleaned the carbs last night and now it idles without help. The guy I bought it from had it for 4 months and never changed the oil or filter, and never had a fuel filter on it which would explain all the junk in the carbs. I still need to synchronize them.

I am happy with the engine. I think I might be able to do better on the frame once I get myself a welder and learn to weld. I am undecided on whether I want to build a whole new frame around the engine or use the existing design and attempt some upgrades.

The only reason I can't drive it at the moment is the weld that held the brake caliper on the frame broke loose and the brake pads were lost. The caliper is not from the motorcycle the engine was from, so I don't know which pads to buy. I do have a neighbor who offered his old motorcycle to salvage parts from, it has good calipers and discs front & rear.

I am unhappy with the design of the rear axle. It does not seem to be designed for swapping out parts (sprocket, brake disc, U-joints etc...) as everything is welded together. I would like to look into some sort of axle kit or try my hand at fabricating one.

The suspension and steering in front also could use a face lift. (rack & pinion from a fiero?)

I have looked into the pros and cons of live axles and single wheel drive. I would like to design or find a 2 piece live axle that has two steel plates that meet and can be easily bolted or locked together when on the dirt or sand for power to both wheels and then I can disengage for driving on hard ground to facilitate easier turning. Has anyone seen a design that resembles this?

I am exploding with ideas on what I would like to do to this thing. I will definitely be frequenting these boards to pick some brains in my journey.

 

[Kenny_McCormic]

Nice, I hope he didnt run it without a filter.

 

[2or3wheels]

U want a limited slip diff rear axle

 

[oorgle]

do not go solid live axle you already have independent rear suspension. if your u-joints are welded to the axle i would just buy new u-joints and new axle shafts and then bolt them together.

if I were you i would not try to build a new rear end i would just swap out anything thats welded together for new parts. the new parts should be able to be bolted on as well. for offroading the rear setup you have is much better then a solid live axle.

you can use the dirtbike brakes but you may have trouble finding a hub to mount the disc to the axle. I'm actually in the same situation. they make go kart hubs but not hubs meant for bikes/quads AND karts.

your not going to find a 2 peice live axle that bolts together to give you live or single wheel drive. you can get a differential but they are expensive and not worth the money for an offroad kart. offroad you WANT both wheels spinning.



the frame looks fine other then it looks incredibly painful to try to get into lol.



your steering setup is not rack and pinion its just a standard hydrolic gearbox torn out of a car. you actually don't need that gearbox at all. it may make turning a little bit easier but i doubt it.




overall it looks like a great project and that 600cc will gives loads of power. you may want to invest in some meatier tires as that 600cc will burn the rubber off those ones in no time.

 

[sayre315]

thats is a big engine
its gonna have loads of torque at the same time have good speed

 

[modelengineer]

With that big of an engine dont worry about a differential, or one wheel drive, or any of that. You will EASILY be able to turn on any surface by spinning the rear tyres (unless you get some massively wide racing slicks or something)

I'm with oorgle, try to keep the independent rear suspension. It's good to have. Best bet would be to just replace the parts that are there with splined universal joints and axle so that you can dissassemble and reassembly easily.

If you want to buy parts such as disc brakes and hubs and such, I would look here: www.edge.au.com
No affiliation, just a happy customer. The stuff they have is REALLY heavy duty, designed to work with even their Hayabusa powered buggies.
I'm sure there are other places to get this stuff in the US if you don't fancy the shipping.

 

[GoAlterBridge]

^^^ I agree ^^^

 

[Dang]

Man that thing look sweet, you might wanna get bigger tires for it. How much did you paided for?

 

[perceptionist]

Saw it on Craigs List for $400, went to check it out and took it for $350. Although the front and rear suspension/steering assemblies could use some improving, oh and the wheel bearings were shot, I think the motor alone was worth it.

I just changed the oil & filter yesterday. Old oil was pretty thin & dirty. Definitely needs new plug wires and plugs. The tires on it now are all cracked and ready to burst so I will be looking around for some. This kart has definitely seen better days, but it is a great starting point for something cool.

 

[Dang]

dude thats an awesome deal, that kart will haulass once you get it up and running.

 

[perceptionist]

Little update. I got the new plugs & wires. Also bought new straight boots for the plugs. Now it idles great and revs ok. I plan to synchronize the carbs tomorrow in hopes that it will smooth out the revving.

Still no brakes, but I am really itching to take this thing for a little spin

 

[redcali]

you can use the dirtbike brakes but you may have trouble finding a hub to mount the disc to the axle. I'm actually in the same situation. they make go kart hubs but not hubs meant for bikes/quads AND karts.

he doesnt need to find a mounting kit as he has a disc already mounted.

just take the caliper into a bike shop and ask them for new pads for it. and if they dont know what it is take it to an auto parts store.

more then likely though, it is a motorcycle caliper of some kind.


i would work on a new front end of some kind. it looks like anything you hit and causes damage that isnt a foot in height will be taken up by your steering setup.

 

[redcali]

and if they cannot work it out, worst case scenario.
you measure the diametre of the hole where the hose attatches to the caliper. which will most likely be 10mm
and buy a new caliper with a 10mm screw and you are done.

 

[I like karts]

look at those beautiful carburetors.

For an axle though, for a kart with that much power, I would just go to the nearest junkyard and take the rear axle from a small car (/w diff)

 

[perceptionist]

How would I make the chain drive motor compatible with the shaft driven diff? I would like to eliminate the chain/sprocket assy altogether if I could find a shaft drive unit to bolt to the motor.

 

[AutoMX]

well you just answered your question, you get a shaft drive unit and dump the back half (90 degree > shaft > another 90 degree that you dont need) and just somehow secure the shaft to the car driveshaft.
weight would be a concern, the car diff, regardless of how tiny the car seems, is gonna be like 1/4 the weight of the engine/tranny you have. way overkill in my opinion, and diff = good on street, bad offroad. if you're gonna have a diff offroad, you pretty much need a locked diff which again defeats the point of doing all the work. you would have a 150lb rear axle which would slow down the kart by who knows how much and every bump would compromise the frame from all the weight flying up and down.

look at the setups on http://www.minibuggy.net/forum/
they build exactly what you have

 

[redcali]

can someone point out the need for two sets of shocks on the rear?
the drive setup you have at the moment is the best for basically all applications of this kart. enjoy it, dont make it more work for yourself!

 

[perceptionist]

I don't know what the idea behind that design was, but the ones w/o the springs are air adjustable if that makes any sense. Perhaps the double shock setup was an attempt to make up for a poor suspension design or old worn shocks.

 

[AutoMX]

bike shocks, when used on [light] cars, are usually doubled up to make up for the weight.

 

[perceptionist]

Well I just got the pads for the brake caliper today and finished welding the bracket nice & sturdy to the frame. I took it for a ride around the block. Absolutely no complaints on the engine/clutch/throttle setup, however it handles like absolute crap. As I mentioned before the steering setup is horrible and the live axle seems to greatly mess up the handling. When I try to turn, it just pushes on straight forward. In order to do a u turn on my street, I had to get out and push it back & forth in like a 10 point turn. Need to solve this somehow, this cant happen with all live axle assemblies does it?

As for the steering I found the front end for sale from a yerf dog spiderbox with rack & pinion steering, couldn't hurt to try it out...