2018 - Ridiculous Mini Bike Build

[Tpdingo]

As they say in Australia...

BEAUTY! BOBS YOUR UNCLE

 

[Mrturbo458]

Haha thanks!!!! Should have another update coming soon!

 

[landuse]

Nice work!

 

[Mrturbo458]

Thanks! I figured out the rear brake lever, oddly enough it's going to be heel actuated... Not what I'm used to, but it is how it has to be, unless I want air brakes haha. I also have determined that the seat height needs to be 6-7" taller than it is now, so I need to make up a seat frame for it as well (hopefully making it look decent as well). It's just a process of trial and error sometimes, but that's what makes it fun!

Have a weld on gas cap on the way, and a few other parts too, hope to get some work done before the weekend!

 

[Mrturbo458]

Small update! I got my brake line parts so I decided to start on the front brake setup. I'm running a Yamaha warrior 350 front caliper and the disc is from the ct70 I think. I turned a spacer to get the disc closer to the caliper, and the bolts are still plenty long. Even with the spacer I have to pull the disc to get the caliper off.

I have decided to change the rear of the frame quite a bit, it'll look better and be much stronger, plus the seat will be in a better spot for me as well. Minor setback though.

Also got the upper caliper mount welded on. Hopefully I'll have the brakes functional tomorrow and maybe I can take it for a little test ride before the frame gets hacked up..... But we'll see how it goes.

-MrTurbo

 

[landuse]

Excellent work as usual Whats wrong with the back end of the frame?

 

[Mrturbo458]

Thanks!

So, looking at the design of the squared u bend on the bottom (what would be the swing arm) I was noticing that the front 90's are basically all that are supporting the back part of the frame from twisting/left to right bending, which for a 212 probably isn't a big deal... But this is a bit different. My boss (engineer) also agreed that it was a weak spot.

Also, I decided my seat height needs raised up at least 6-8", and it is going to look kinda silly if the back section stays the same.

Hopefully I'll get it modified here in the next few days, and it'll make more sense. I'd draw it up for explanation purposes, but I'd rather use the time to work on the bike haha. Needless to say it may have a bit more of a sport bike-ish back end if I can pull it off.

 

[Mrturbo458]

Here is the latest update video:
https://youtu.be/6lOfdifsXtA

It helps explain the seat/frame change a bit better. And it has a teaser on the Baja blitz build that's coming up.

Got some of the frame re-work done, waiting on my 1.25" tubing to continue.... Then l can weld it up and add the seat brace and gusset bars in and chop out the unused portion.

Hope to get my gas cap and weld that up to the tank as well, and still working out some brake system issues as well.

-MrTurbo

 

[Tpdingo]

Rotate the frame 90 degrees and make a engine powered unicycle. Rename it the Death-O-Matic.

Just kidding, I love the progress of this thing.

 

[Mrturbo458]

Lol it could still be named the death o matic.... But I don't want to jinx it.

 

[Joe-405]

I would have added a hoop in the back of the original seating area. I’ve seen a few guys try putting their seat higher but it was unstable and uncomfortable so they changed it back. The closer you can get to the ground and farther back the better off you are for dragbikes.

Either way it still looks great tho. Build threads are always for improvements or ideas which is why I like them.

 

[Mrturbo458]

Thanks Joe!
Yeah, I don't like how high the seat is, and it feels like I am up in space sitting on the bike. Unfortunately my legs are super long (I'm 6'4" and it's mostly leg length) so I am finding it to be a challenge to fold myself up on the thing. The seat to peg distance had to be increased, and the pegs can't really go much lower. The seat hoop is only tacked on in case I need to change it up. A low c of g is the key, but it's all for nothing if I can't ride it LOL!


The sad part is I think I am going to rework the front of the frame next. The bike just doesn't look right to me, and I think I can modify the ergonomics of the bike a bit more. If I can lower the bike as a whole, I can get back some of the 6" I added to the seat height, thus lowering the CG. I think the rake angle needs kicked out a bit more, and the handlebars need moved up (steering bearing tube) and then the forks need extended to set proper ride height. Should be pretty simple to lower the rear down as well, all it takes is more time and elbow grease!

What is a good ride height? 2-3" bottom of frame to the ground?

It's all trial an error, but I enjoy solving puzzles and building things!


Stay tuned for more pics! I'll be posting more up soon here.

-MrTurbo

 

[Tpdingo]

Thanks Joe!
Yeah, I don't like how high the seat is, and it feels like I am up in space sitting on the bike. Unfortunately my legs are super long (I'm 6'4" and it's mostly leg length) so I am finding it to be a challenge to fold myself up on the thing. The seat to peg distance had to be increased, and the pegs can't really go much lower. The seat hoop is only tacked on in case I need to change it up. A low c of g is the key, but it's all for nothing if I can't ride it LOL!

What is a good ride height? 2-3" bottom of frame to the ground?

It's all trial an error, but I enjoy solving puzzles and building things!


Stay tuned for more pics! I'll be posting more up soon here.

-MrTurbo

Put the seat low and put the pegs out far and use your knee to help yourself fit.
This, well maybe I just drew a chopper but here you go.

Also, my prediction is that MrTurbo has a huge head and wiggly arms.

 

[Mrturbo458]

LOL That's a very nice drawing.... yeah, that's a chopper.

If you watched my youtube updates you'd know if I had a huge head and wiggly arms

 

[Tpdingo]

LOL That's a very nice drawing.... yeah, that's a chopper.

If you watched my youtube updates you'd know if I had a huge head and wiggly arms

Big head...not so much. Wiggly arms...I was right

 

[Mrturbo458]

Haha yup.

 

[Mrturbo458]

Here is the latest on the progress. Got the gas tank filler cap welded up, machined a bung and tapped it 1/8 NPT, welded that to the tank. Leak tested it all, and no leaks! Next I need to weld up mounts for the tank.

Got the rear frame section hacked out, though it looks odd now, it isn't complete yet... But it is taking shape.

Also got a stick of stainless pipe for the exhaust, might need to expand the warrior header a bit to match the pipe, and then figure out how to mount it. (Looks ridiculous right now).

Definitely going to rework the front end, so I'll see how that changes things ergo wise and CG wise.

-MrTurbo

 

[Tpdingo]

What I'd it if we're me Id make a small vertical cutout in the tank and mount a glass cover so you can see a little strip of how much fuel is in the tank. That motor is going to be pretty hungry for fuel, sp you'd probably want to know more than approximation or opening the lid.

Like this:

I think you could do it by drilling two holes, putting two 90 degree fittings at the top and bottom and putting come kind of clear tube right in the middle. I think the floating gas gauge look might look pretty cool.

 

[Mrturbo458]

That would be pretty cool! I'll have to look into that.

It will probably do pretty good on fuel consumption I'm guessing. Plus I don't need that much fuel to do a few drag runs here and there. But it would be nice to see the fuel.

 

[Mrturbo458]

Ok, so I got ambitious today (and I have to work all weekend) and I changed a few things around on the bike.

1st being the tube angle going to the steering bearing tube, and the length of that tube (made it shorter). This does a few things.....

It increases the rake angle (good for drag bikes), it looks better I think, more comfortable seating position, and it allows the seat to be moved back a little bit. And no, the crotch stabbing bars are not staying

Cons- I'll have to extend/reinforce the forks (more bending stress on them), I have to move the seat back a tad bit (which makes the seating position tougher), and I might lose some wheel base (most likely not though).

I like the lines of the bike much much better, and I came up with a few ideas for the foot peg location that will work with a lower seat height. But the gas tank will look slightly more out of place, but I can always change that later.

I was also stealing measurements off the doodlebug and seeing why I can ride that comfortably (besides peg location) and that helped me think things out.

All I can do is give it a shot and see if it works or not! Worst that happens is I'll have to change it again lol

-MrTurbo