GHS Shop Class Build- Alignment issues

[gijoe985]

Hello all,

It's been a long while since I have posted, but we finally got a kart for our shop class to work with. From the kid plate, it appears to be an Emmick kart. I honestly know very little about brands, etc.

Right off the bat we've got two things to work on. 1) the chain does pop off when you go at it hard. But more importantly 2) the kart understeers HORRIBLY.

Right off the bat, what I've noticed is this, when you turn the steering wheel all the way in one direction, the outer wheel will begin point outward. I.e. the pitman arm goes past 3/9 o'clock and begins to turn out again. So, do we need a stop to limit the steering, or is there some other issue/solution. I'm a car guy, so I'm trying to wrap my head around the simplified kart setup.

This was a junior kart which was modified some for a larger guy. In the end I'll probably want to change the steering column angle, and move some of the gas/brake pedal linkage to accommodate someone with longer legs. But for now, being able to turn would be great.

I also think the turn radius is poor. I was somewhat tempted to drill new holes to locate the tie rods closer to the spindle. Just barely. But I think that'd help our turn radius. Right now I cannot even turn around in our shop and it is pretty decent sized. I assume one should be able to turn around in a 16ft wide space.

I can post a video and some pictures later if that helps. I am excited. This looks like the perfect project for us. I hope to replicate this cart and make 2-3 more soon.

 

[HONEYBADGERFTW]

1)"The chain on your go kart should be lubricated before every ride. The chain should also be checked for tightness on a regular basis. If the chain is too loose a popping sound can be heard and the go kart will jerk under acceleration, or the chain will just jump off altogether. If the chain is too tight it will be noisy and bind, this can be felt by pushing the go kart with the motor off."

2) Look at this :https://www.bmikarts.com/Go-Kart-Steering-Alignment I also had alignment issues, until I discovered that the used kart I purchased was supposed to have a spacer between the kart and wheel hub on each front wheel, they were like this \---/ when steering was straight, now they are like this |---|.

I'm no expert by any means, hope that helps though.

 

[landuse]

Your sprockets are probably not aligned perfectly or your chain might be too loose.

You probably will find that something on the front of the kart is bent so the steering is not so great, or you might find that the kart has horrible steering geometry from the get-go. Post some pics of the front end of the kart from the top. A pic of the top with the wheels pointing forward, and then a pic each of the wheels turned either way. We will then be able to see.


Ackerman steering and geometry + potential fix
http://en.wikipedia.org/wiki/Ackermann_steering_geometry
http://www.ihpva.org/Projects/PracticalInnovations/ACKERMAN.GIF
http://www.kartbuilding.net/racingkart/Old_Racing_Kart/ackerman.htm
http://image.absoluteastronomy.com/images/encyclopediaimages/a/ac/ackermann.svg.png
http://blog.kartbuilding.net/2007/07/12/steering-geometry-and-setup-for-go-karts/
http://www.diygokarts.com/vb/showthread.php?t=11760
http://www.diygokarts.com/vb/showthread.php?t=11798
http://www.rctek.com/technical/handling/index.php
http://www.diygokarts.com/vb/showthread.php?t=23785

 

[gijoe985]

I'll get some pictures up. I'm very familiar with suspension geometry. I used to work on formula cars. The irony is that I've just never seen a problem like that before. And I'm trying to think if I just need to limit the steering or if there is something I am missing...

 

[jandj]

I’m interested to see your pics.
Post a pic of the ID tag also.
Some racing karts use steering stops.
If we know what model it is, it’ll make things easier (hopefully).
We can at least see what the steering is supposed to look like as compared to what you have now.
Also, when you say “Junior Kart” do you mean the Emmick Kadet model for older kids?

 

[gijoe985]

Steering at 12 o'clock

Steering at 10 o'clock

Steering at 8 o'clock

All that said, I am a total noob concerning karts, so the guy I bought it from said it was a "junior kart". I assume that would be the Emmick Kadet. I don't see anything on the kart that states a model except that it said Emmick on the floor pan.

Here is another picture of the whole kart-

 

[jandj]

Here’s a pic of an Emmick Kadet Kart.
You can see the where the Pitman arm attaches to the steering shaft is higher up from where it goes into the mounting tube and the tie rods are straight.
I can’t say why yours sits lower.
Maybe you can pull it up and put a lock collar above where it goes in the mount, assuming there’s enough left in the mount.

 

[FieldstoneDriveKarts]

http://www.vdm46.com/emmick-kart-id.html

---------- Post added at 09:53 PM ---------- Previous post was at 09:47 PM ----------

My Emmick has a straight pitman arm, with one bolt through both tie rods ends.

 

[FieldstoneDriveKarts]

My Emmick Elite kart

 

[FieldstoneDriveKarts]

Btw, Emmick karts usually have a model/year code on the back bearing hanger, or under the brake caliper.

 

[Flyinhillbilly]

What if you mounted the tie rods under the knuckles? That looks like that should help with the geometry some.

 

[gijoe985]

I am going to try mounting the tie rods from the central hole and see how that changes things. This will be a fun project for kids to learn on.

 

[jandj]

Is there enough of the steering shaft going through the lower mount that you can loosen the upper steering shaft block and pull the shaft up to the point where your tie rods are straight instead of angled like they are now and then readjust the length of the tie rods so the wheels are straight?
If so, I’d try that before I remounted the inner rod ends.

 

[gijoe985]

Is there enough of the steering shaft going through the lower mount that you can loosen the upper steering shaft block and pull the shaft up to the point where your tie rods are straight instead of angled like they are now and then readjust the length of the tie rods so the wheels are straight?
If so, I’d try that before I remounted the inner rod ends.

I'll give that a try. Not sure yet.

 

[gijoe985]

Ok, we made the simplest change that we could that required no drilling or irreversible procedures. Thus far it made a big difference. The turning radius was increased and the outer wheel no longer turns outward while turning. We've had the chain pop off again and I'm sure it needs to be tightened.

One thing at a time though.

 

[jandj]

Saw your post at Bobs, sorry all you got were snarky replies about Ackerman and no help.
Like every site, there are always a few who revel in their own knowledge.

 

[gijoe985]

Haha, thanks. Yeah, I was trying to explain that while Ackerman is a related issue, the problem I was running into was kind of unique to a super simple (kart style) steering and that you'd never see that on a racecar. Using the single hole to mount from has helped. If we decide to go with that long term I may need to cut off the outer parts since it binds slightly.

 

[jandj]

What you did was effectively what I was thinking when I mentioned raising the steering shaft.
By straightening the tierods you basically lengthened the “throw” of your steering linkage.
That lessened the distance they traveled and by extension the amount the wheels turned.
Hope that made sense.
You’ll find that unless you’re driving a really tight twisty course you won’t be turning full lock frequently.

 

[gijoe985]

Well, We've got our steering doing MUCH better. In the long term my goal is to build more of a concession kart. Very safe, not ridiculously fast, safe... but also with certain features (like hydraulic brakes) that make it more like a real car, so kids can learn some basic principles.

I may make some sort of a cover that covers the entire rear axle, brake, and chain area.

 

[KartFab]

Saw your post at Bobs, sorry all you got were snarky replies about Ackerman and no help.
Like every site, there are always a few who revel in their own knowledge.

yeah it seems like that's becoming more common in the forum there like a magnet for *******s who group think.