Motorcycle Powered Kart: Father Daughter Project

[Dale]

I'll just leave this here for more info on the engine. Found it on mychinamoto.com forum.

Hey dualero thanks for that info.

and the sheep hotel screen shots....? ;D ;D

Ill see what I can do! :-D

nice models, does your software also by any chance have a stress simulator built in?
I used autodesk inventor for several frame designs, and the fram simulator is an awesome tool.
Let's you apply forces anywhere, any way, shows you frame deformation, peak stresses etc...

Oh nice! Great looking frame. Im more familiar with Solidworks, which as you probably know has very similar functionality to the Adobe product.
FreeCad does not seem to have Finite Element Analysis, but I could be very wrong. A quick google gave me a ton of options.
Free apps like LISA ( http://lisafea.com/ ), will give the cheap seats Free Cad users this functionality.
I haven't tried it yet, but apparently you save out your object as a .step file and import into Lisa.
Most definitely worth getting my teeth into this, as its going to take a bunch of guesswork out of things.

.... AND onto that note: my current progress: (again WIP)

Frame is starting to look the way I want it to, but I've got under constrained areas, and as well as some areas that can potentially be optimized.
The blue tubular areas are the new framework, and the grey is the existing framework.

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STEERING

• The ATV has a simple system for pushing and pulling the steering rods, and initially I was just going to use that.
• But the handlebar will definitely give more leverage than a small steering wheel.
• And "A" has the strength of .... an 8 year old little girl .
• I figured that it wouldn't be much fun if she was wrestling the steering.

Late'ish model VW Rabbit.

Picked up a steering box from a junkyard. The guy phoned around and found me a steering column at another junkyard.
Waited while they removed it from the car for me.
Got a new universal linkage.
Bonus was that the Rabbits steering column has the clutch and brake pedals attached, so Im going to incorporate these.

I got an adapter for the VW column to fit our aftermarket steering wheel.

 

[farmer92]

just out of curiosity, what sort of weight figure did you come out with for that frame?
Granted that "A" will probably not be racing this around the nurburgring anytime soon, but i would be interested to see how this design handles torsional stress.
Any chance you would send me a STEP or IGES file to test it?

 

[Dale]

Excellent! Yeah! Thanks.

Ill Pm you and we can sort out how I can get it to you.
And then feel to post your findings here. I'm sure there will be something to learn from it! :-D

 

[Erskine]

I'm interested in hearing how the motor performs. I've built a trials outfit with a 150 big bored from the 125, that hauls two adults well. I'm now building a small road outfit and I'm considering boring and stroking a 125 bottom end using off the shelf parts to get me a 200. I like the pushrod engine. We've had the Honda CG 125 in the UK since the early 70's, and the design has beyond stood the test of time, it laughs at a life time of abuse getting passed on from one spotty 17yr old learner to the next. Some CG's taught whole towns to pass their bike test. Enjoyed reading the story so far.

 

[DohcBikes]

Looks like it's going to be heavy. That's ok, just an observation.

 

[neevo]

Looks like it's going to be heavy. That's ok, just an observation.

That was my impression from all the extra tube going in. Be interesting to see how the little motor copes. Given its for a daughter though maybe a bit down on power to weight is a good thing.

My original concerns were with the wheel mounts. I was interested to see if a small quad wheel would not only support a spacer but all of that extra frame weight too. Seemed a bit light.

I have no idea what I'm talking about with these things though, so I assume it should all be fine (partly posting to get the updates

 

[Dale]

This is 26mm OD tubing guys. Keep that in mind.
But let's see what Farmers findings are.
And we'll take it from there.

 

[Dale]

http://www.thyssenkruppaerospace.com/materials/steel/steel-tube/weight-calculations.html

mmm. According to my manual calc, frame currently weighs in at around 60kg.

 

[Dale]

Density of mild steel is 7.850 g/cm3

 

[Brodie]

On the note of frame weight, engine performance and throttle limitation, why not fit a large rear sprocket to up the "grunt" whilst lowering top speed.

 

[Dale]

Brodie, solid idea. Its currently got a 15 drive and a 46 rear. I could definitely go up a few teeth without having to worry *too much* about ground clearance.

I pushed up the rear sprocket on my NSR 250, and got definitely got a good result from it. Cant remember what what the ratio was too long ago!

http://www.dotheton.com/forum/index.php?topic=37055.0

Here's another project Im busy with. Rear is a 56 tooth - had to have it specially made up Check out the diameter on that thing! ha ha

 

[Dale]

... while Im talking NSR's ,and going SO OFF TOPIC HERE!
This was my little MC21 Track bike.
We all ran no filters.
Had sets of jets, and you would jet the bike for the morning / afternoon / entire day - whatever.
Lots of opinions on that Im sure! But it worked. And it was what everyone was doing at the time.
And I dont have the bike anymore. So it doesnt matter. Lets talk Karts!

https://www.youtube.com/watch?v=YdP1KmW-CdU

 

[Nj732port]

all this weight talk reminds me of when niki lauda is telling his crew the car is too heavy and then asks for titanium

I think brodie had a good idea about the sprockets/gearing

 

[DohcBikes]

Brodie, solid idea. Its currently got a 15 drive and a 46 rear. I could definitely go up a few teeth without having to worry *too much* about ground clearance.

Much easier and cheaper to install a smaller cs sprocket. You can get as small as 11 tooth, maybe smaller.

 

[Dale]

Yeah exactly!

 

[Erskine]

I'm running 15/45 on my outfit and that's a good ratio for a mix of lane and field work. These engines are so torquey it's only when you drop the gearing that the capability becomes apparent. I'm planning on doing some proper off road stuff later this year and will probs go up to 52 on the back for a real granny 1st gear ratio.
The competition trials bikes that have had the OHV engine swapped in place of the OHC use 12/60.

 

[Dale]

Thanks Erksine. Good info!

BTW, I did a quick search on ebay and these motors are selling for between $1100 and $1400 (!)

 

[Eleganten]

This is just amazing! What do you do for a living? The design work is excellent!


Sent from my iPhone using Tapatalk

 

[Dale]

This is just amazing! What do you do for a living? The design work is excellent!

Thanks for the compliment! I'm just a regular garage guy.

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@FARMER: If you havent done any tests on the frame, I'd hold off ... Ive got a lot of changes Im currently busy on. Its still going to look like an X-Wing from the back tho! Ill post these when I've done them, and we can regroup in this.

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My dad unexpectedly popped in today with welder in the trunk! I honestly had no idea.
Miss "A" went to watch movies with her mom and do girl stuff (she would just be too curios, and wouldn't be able to help herself from looking at the welding going on)

My dad and I had a look at what I had been playing with in CAD, and he gently told me where it was good, and where we could improve things.

So with plans in hand, we started!

My bike trailer doubled up as a type of a jig today.

I cut and grinded (mostly). He welded. What an awesome day with my pop!

In case you were wondering, I didnt look while taking those pics!

This is how far we got today. We should be able to finish the frame with one more days work.
My dads pipe bender is on the farm, and hes only going there in a couple of weeks, to bring it back.
Ill be in San Francisco when he gets back, and Ill only be able to work on the Kart again in April. :-(
Had so much momentum going! All good.

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Did another little exercise. Ive got a spreadsheet going now, where Ill be weighing in all the final parts as we go along. Frame now has a target ceiling of 20kg. This is where we currently are at.

 

[Tune-A-Fish]

Triangulation is a good thing. the two mid ladder bars could be an X. One long bar and two short, Speedway Motors sells a cheap notch cutter for tube also.

Looking good!