2018 - Ridiculous Mini Bike Build

[Mrturbo458]

Nope, I will upon final assembly though. Just in case I need to take it apart or change something. We're a ways off from loctite assembly, sadly. Haha

 

[Mrturbo458]

I've received just about all of the parts I need to get cracking on this thing. Need my sprocket hub and axle bearings (Monday) to really start frame work.

I have all the stuff for wheelie bars, and pretty much everything else for the engine, brakes etc, minus a few components. Sprockets, chain, air filter, new levers, and the front wheel hub showed up for the ct70 front wheel I'll be running.

The air shifter is making great progress, waiting on the kill box board design/manufacture, and 2 12v solenoid coils. The regulator and gauge are for testing purposes only, btw.... It will be push button up shift, no clutch no blip, and push button down shift (with clutch obviously).

Haven't had much time to just sit in the shop and fabricate/weld on it, but I will soon!

-MrTurbo

 

[Joe-405]

MPS make a nice compact kill for the ignition for full throttle shifts. It’s only $160.

 

[Mrturbo458]

Yeah I saw that, if I can make one with parts the shop has it'll be free though, and I can add features to it that the mps doesn't have. Plus it's more fun to build it!

 

[Mrturbo458]

Got some work done on the frame today, cut the rear wheel hoop apart to be widened and got the frame extension tubes cut and notched. I had to turn the inner sleeve tube in the lathe (.010" off) to get the 13/16" tube to fit in .095" wall 1" tube, but it fits nice and snug. At this point I think my rear axle is going to be 16-18" long, but I need to do more mock-up and testing for a final number. I think I will barely get by without using a jackshaft if I machine/weld up an offset sprocket for the transmission output. The Warrior 350 quad calipers for the front and rear seem like they will be perfect AND they will provide lots of stopping power as well.

Didn't take any pics today, (sorry!) but I did upload a new YouTube video just now (for those that aren't using dial up internet haha jk!!!!)

Here is the latest video link! ---> https://youtu.be/E-sfnGsaJL8

I will have progress pics up tomorrow though!!!!!!

-MrTurbo

 

[Mrturbo458]

As promised, pics! (pic heavy, sorry!) I got the rear section of the frame tacked up, ended up widening it 3" for tire, brake, and sprocket clearance. Lathe turned the inner sleeve tube, as I did for the main frame section and added the 3" extension tubes in.

Using a scrap of conduit, I made a mock-up axle to get a rough idea of the layout and spacing of the components. The new wheelbase should be around 58-60" (hard to measure accurately alone)

Once I am happy with the rear section, I will weld it up fully, and then weld the front portion of the frame back on to the widened rear, and then figure out the home of the engine and start making engine mounts!


Hope ya'll are enjoying this build! I know it's a bit overkill, and might not make sense. Normally I would hunker down and have it built in a week, but I'm really taking my time on this one so it's built well and so I can have fun on it later and not worry about problems.


-MrTurbo

 

[landuse]

Looks cool, but I was just wondering if you aren't worried about the tyre hitting the top bar if you go over a bump or something. You have so little space between the tyre and the frame that it looks like it might be a problem

 

[ezcome-ezgo]

This gap will solve the clearance issue...

 

[Mrturbo458]

Ez is correct. If you look at where the bearing mount is, you'll see that it's about 9" (18" tall tire) lower (on center) than the mock up axle. The picture is showing width, primarily.


-MrTurbo

 

[Mrturbo458]

Got the rear and bottom of the frame welded up all the way!

No, it isn't done, it needs more bracing, and real axles, and 100 other things. BUT I hacked it together just to give you all, and myself a concept of what it's going to look like.

With wheelie bars, it's almost 10 ft long! Crazy. I might shorten the bars up a bit, but I was reading 80-100% of the wheelbase is optimal for bar length. But I think I'll see if I need them first. I can also make some quick release pins to take the bars off for transport/storage.

Next is figure out the engine placement, frame bracing, top bar, engine mounts, etc. It's definitely taking shape, and coming along.


-MrTurbo

 

[landuse]

This gap will solve the clearance issue...

Ez is correct. If you look at where the bearing mount is, you'll see that it's about 9" (18" tall tire) lower (on center) than the mock up axle. The picture is showing width, primarily.


-MrTurbo

Aaah. I didn't think to look at where the bearing hanger was situated

 

[ezcome-ezgo]

Looking good!

 

[Mrturbo458]

Got the lower section of the frame back together, it needs a lot more reinforcement, and I'm going to change a few things up on it. Need to get some scales and figure out weight balance for the engine placement, but I kinda want to just pick an optimal location and run with it. We'll see how serious I get with it.

Keep in mind, it has fake axles in the pics and they are for mock up/photo purposes only....

Ordered the rear axle, so that will help with mock up, and assembly. Going to order more tubing for the upper rails and bracing. Then it's on to engine mounts, and then it'll be engine testing time!

Also, here is a YouTube update video: https://youtu.be/69oipUXAmBc


-MrTurbo

 

[landuse]

Looking sweet so far. You speak about bracing.......will the circled area get some bracing too?

 

[Mrturbo458]

That area is going to get completely redone/braced up. The main weak point right now is the middle of the frame. It's pretty flexy, but that will get fixed.

 

[ezcome-ezgo]

I am thinking custom fab'ed I-beam.

 

[Mrturbo458]

Haha that's awesome.

 

[Mrturbo458]

And so the front modifications start.... Been pretty busy lately, but I got this done at least. It needs more love, obviously. But the idea is to have 4 tubes supporting the bearing tube for the handlebars. Need to spend a bit of time making some tubes and then figure out engine placement weight balance wise and then get busy making engine mounts and frame bracing stuff.

-MrTurbo

 

[Mrturbo458]

Don't have much of an update sadly.... I picked up double the hours at work (good for money, bad for extra time) so I'm super busy. But I am still working on the mini bike, and I'm making a little bit of progress.

Got the engine mounts drawn up in CAD and made some templates to cut them out. This will at least help keep the engine level while I figure out the weight balance.

Stay tuned, I should be getting more done soon!

 

[Tpdingo]

I am thinking custom fab'ed I-beam.

No you are doing it all wrong.

Put a big V8 right in the middle.

Fill the rest of the frame in with brazed aluminum.

Solved the seat, the engine, and the excuse to cash out on the life insurance policy all at once.