Anything Goes! Another Dutch minibike build from scratch.

#41
Today after work I was able to make a little progress. Here's a short update.

First I cut off the over length of the front fork tubes and I milled down the tubes, where the front axle supports will be welded in place.


Front forks with the front axle supports tacked in place.

I also tacked the upper frame tubes.

Checking the fitment of the new seat with the upper frame tube. It's a perfect fit and the tube bending radius is the same as the radius of the seat.
The seat is an aftermarket "short version" buddyseat of a Puch moped. Reasonably priced.

Now I need to find a way to notch the tubes in the correct angles, diameters, offsets and places. All this in a way that combined they'll become a frame.

"Stay tuned"
 
#43
Wow...!

It looks like your math formulas as to where to bend etc, really pays off in getting the second frames bends to appear identical to the first frame.

Great work, and thank you for all the detail and photos.
 
#44
Wow...!

It looks like your math formulas as to where to bend etc, really pays off in getting the second frames bends to appear identical to the first frame.

Great work, and thank you for all the detail and photos.
Thanks. Here's what I did:
First I calculated the total length of the tubes and I added some extra length on both sides. I cut all tubes the same size and marked them all together as to where to start the bends.
When putting the tubes in the tube bender, I placed the marks at the edge of the bender die.
After I bended the first tube I checked and measured it and as it was all good, I bend the others as well.
 
#45
Well, we've got some things done this weekend.
Below you'll find some pictures of past weekend.


This is the upper frame tube, while it is being notched on the Bridgeport mill. I tacked it to a structure of some square tubing, which I clamped in the vise. This worked out great. Correct angle of notching. Unfortunately the other tubes couldn't be notched like this, because they wouldn't fit in the correct angle on the Bridgeport...


...So I used a print out of an online tube notching calculator for the side frame tubes.


Before cutting with a grinder, I double checked if I would cut at the proper spot.


Here I am double checking and measuring if the tubes have the correct position in the frame jig before my daughter would tack weld them. This was time consuming, but the effort paid off. With dimensions I kept very close with the drawings. If you don't, you'll end up with grinding parts.


My daughter tack welding the frames.


2 Frames tacked by my daughter and some help of me.


2 Front forks already tacked.


Frame, front fork, gastank, seat and some pieces of wood to keep it all together. I'm very happy how this turned out so far.


Engine mounts bolt together with the engine mounting plate. Measuring tape and a drawing with dimensions to place it where it belongs. On the back of the engine mounts is a mounting plate for the rear fender.


Perfect fit of laser cut parts. No grinding needed. I love it when a plan comes together...


Rear axle supports in place. These have been milled, where the axle slides in from the back. This prevents the axle from turning.
To keep the correct width of the frame, I placed some pieces of metal (with the correct distance) between the tubes, before tacking the rear axle supports in place.


Here are 2 frames and forks welded. Including the fender mounts.
The engine mounting plate is angled, which allows the use of a torque converter.

Gastank mounts and the mounts for the seat and battery will be added later.

"Stay tuned"
 
#46
The spatters from MIG welding the frame and forks have been removed and some ugly welds have been cleaned since last update.

Before adding the gastank mounts I have welded the gastanks. I think they don't leak, but will have to check that to be certain.

I added the fillernecks and welded the gastanks. Made from 1,5mm thick stainless steel sheetmetal.

To mount the gastanks I plan to weld 3 nuts (M8) to it. The lasercut mounts are basically some metal strips with 8,5mm holes in them. 1 mount goes on the back on top (2 bolts will hold it in place here) and the other mount goes in the front on the bottom (1 bolt will hold it in place here).
I'm not sure when, but you'll see in my next update.

"Stay tuned"
 
#47
I have spend some time in the shop again and got the tanks and seats mounted to the frames. I also checked the tanks for any leaks and they are fine.


Pictured here is how some pieces of wood can be helpful to hold the gastank in place, while tacking the tank mounting brackets.


Both minibike frames with their gastanks. The gaps look good to me.


The filler-neck is right in the middle of the frame. And this picture also shows the top mounting bracket, with the 2 nuts welded to the gastank.
Don't mind the long bolts as I didn't have any shorter ones, yet.


This is the bottom of the seat (aftermarket Puch moped seat). Here it shows where the original mounting bracket was located, which I cut off the seat.
I first added 4 blind rivet nuts in the seat. The new seat mounting bracket is now bolted to the seat.


Next step was to place the seat (with the mounting bracket bolted to it) where I wanted it, with the correct gaps. Some pieces of steel helped with creating the correct gaps. When it was in place, I tacked the seat mounting bracket to the frame.


Here is a view of how it looks like from the bottom. As you can see it is a bit hollow seat. This gives me space to add a small 12V sealed lead acid battery.
The battery holder is the next thing to weld to it. It will also carry some switches, a charger plug and a fuse-holder.

"Stay tuned"
 
#49
I'm back again.
I haven't done much to the bikes lately, but below are some pics of the progress since last update.
Keep reading, because it is a rolling chassis by now...


I have added the battery containers/brackets. It's a small 12V sealed lead acid battery, to power the analoge tachometer. In the rear section is a support to place a charging socket, fuse holder and some switches.


Rear brake caliper bracket mounting to the frame.


Front brake caliper bracket mounting to the fork.


Time to put tires on the new rims. Tubeless.

When I build my first minibike, I made my own fenders for it and at the time I did make 6 pcs (4 spares). I will be using the spare ones for these bikes.
Below are some pics of making these fenders.

I placed the tires and the engine with torque converter on the bike. I also located the fenders to see the clearance between each part.

Torque converter installed. I looking for a way to put the driver closer to the engine. If possible...


Clearance torque converter to rear fender.


Clearance torque converter to frame.


Still a lot to do.
 
#53
Looks Great! I love the gas tanks
Thanks! And for this bike I'm using the same tires as you're using at your scratch build Harrison.

Well, the minibikes needed foot-pegs, but I ran into a small problem with clearing the engine with torque converter while feet on the foot-pegs.
The problem is solved and I have made some solid foot-pegs. I was planning to weld a straight tube to the frame to be used as foot-pegs, but that wouldn't do the minibike justice. So I took the sample 90 degree bends (bends that I made to "test" the tube bender) and cut them in half.


One end will be welded to the frame and the other end is plugged with a cap nut welded in place.


Foot-pegs welded to the frame. The height is the same as the front- and rear axle.

With the foot-pegs in place it's time for another thing to do; Intake and exhaust manifolds.
Because I have drawn the intake and exhaust flanges (that already have been lasercut), I can easily measure what size tubing I need to exactly match the cylinderhead of the GX160 engine.
Because I don't have the matching bending die (and not willing to purchase for that price) I will be making the intake and exhaust with stainless welding bends and straight tube.


This is how I cut welding bends. I tack weld it to a metal support I made, which is clamped in the vise of the bandsaw. This works easy and no matter what the angle is, the bend is cut at the right place. Just make sure, the metal support is nearly touching the bandsaw.
Here is a 90 degree bend cut in 2 pieces; a 60 degree, which I'll need for the exhaust and a 30 degree, which I'll need for the intake.

Tomorrow some more work to do.
 
#54
Another weekend well spend; I've made intake- and exhaust manifolds for both minibikes.

Both are made of 26mm inner diameter tubing/welding bends. Because the "D" shaped intake port circumference is smaller as this 26mm inner diameter, I had to make a special piece to go from 26mm inner diameter round tube to the smaller "D" shaped intake port.


I took a piece of tubing and cut out some metal to get the right circumference.


Squeezed the tube together and welded it.


Next step was to make the "D" shape to the tube. Pictured above are the tools used to do so.


Adding a 30 degree angled welding bend in the right orientation.


Added the Mikuni flange. It needs a little bit of cleaning on the inside. But overall, I'm happy with the result.


After welding I milled the surface to a flat surface.


Carburator attached. Everything is level.

So much for the intake; now let's see how I've made my exhausts, including muffler.


These are the parts I used to make the muffler. Outer tubing, perforated inner tubing and end plates. All stainless. Muffler is filled with isolation between the inner- and outer tube.


A small piece of round tubing used to go from the "D" shaped exhaust port to round.


Adding the 90 degree and 60 degree welding bends.


Muffler added. This is the complete exhaust. It's short and the sound is muffled...

"Stay tuned"
 
#55
Hello again,
After most parts had been made, I had to mount the fenders.


This is how I measured and draw where to drill the mounting holes. I drilled the holes a bit oversize to make sure I can line up the fenders correctly with the tires.


Fenders mounted on this "General Lee" frame. The fenders for the second "Herbie" minibike have also been drilled, the exact same way.

With this most parts have been made and it was time to start spray paint with cans. After the dismantling and preparations for paint. And I also welded some brackets to the frame which I can use to ziptie the cables to. This will hold the cables solid where I want them to be. Unfortunately my welder ran out of gas, so I finished it at work.

I took all parts from the workshop to my house (10 miles seperate) and decided to spray paint it at home. Weather forecast for this week is ideal for painting outside. Next week is a different story.


Frame and fork of "General Lee" minibike with a light grey primer.


Gas tank and fenders also with the light grey primer on it. This primer was really nice to spray. It covered the frame in 1 time.


This is the frame and fork of the "Herbie" minibike. Because of the white color it will get, I choose to go with a white primer. This primer wasn't as easy to spray as the grey version. But I managed to cover the frame in 3 times.

That's it for now, next time there will be more colorful pictures. I hope.
"Stay tuned"
 
#57
Today after work, I spray painted both frames and parts.
Yesterday I sprayed primer on them and I didn't sand them after the primer was applied, as I didn't think it was necessary to do so.
Both minibikes are sprayed with 2 layers of spray paint and 1 layer of clear coat. No sanding between any layers.


General Lee minibike after 2 layers of spray paint (ral 2003) and 1 layer of clear coat.


Herbie minibike after 2 layers of spray paint (ral 9001) and 1 layer of clear coat.

I'm very pleased with the result so far.
Next thing will be to paint the intakes, exhausts, engine covers and recoil starters.

Greetings,
John
 
#58
Since last update the intakes, exhausts and shafts/axles (for both bikes) have been spray painted, too. Also 1 engine cover, 1 recoil starter and a brake caliper set for the General Lee bike is spray painted, by now. Everything in a matt black color.
That engine cover and recoil starter was in a bad shape and needed some attention. The engine cover and recoil starter for the Herbie minibike look good and don't need painting.

As I do have my own Roland vinyl cutter, I used it this morning to make some decals for both minibikes.


With design software I created the decals for both minibikes. The designing started some weeks ago and got me busy some evenings. Pictured above is a design, just before it is send to the vinyl cutter.


The vinyl cutter doing what it does best: cutting vinyl.


Creating and applying the decals. Pictured here is the decal applied to the freshly painted recoil starter.


I also replaced the old, worn rope with a new and longer rope. It is a 5MM polypropyleen rope. It looks strong.


Decals made and applied to the front fork of the General Lee minibike.

After all decals had been made and applied to both minibikes it is time to start final assembly of both minibikes.


We started with the General Lee minibike, but will build up both at once. I only have 1 lift, so we have to switch between the bikes.
The LED lightning in the workshop makes the colors in the pictures a bit flat.


Fork, front wheel assembly, rear wheel assembly and gas tank mounted.

"Stay tuned"
 
#59
Today we finished with the first start of the General Lee minibike and we started the day with assembly of the other minibike aka Herbie.


First I had to put those tires on the rims. To get and keep air in the tires I used a strap around the tire. This makes the beads go outside, just enough to get some pressure in them (not to much with the strap around it).


Herbie on the lift and the front fork mounted to the frame.


Fenders and gastank mounted. Also applied some decals on the fender mounts.


I really like this color combination.


The front- and rear axle have been assembled and together with the wheels they have been mounted in place. Next thing was to mount the calipers. For this bike I kept them red.

After the partial assembly of Herbie, it was time to switch minibikes again.

General Lee back on the lift. Mounted the engine, torque converter and aligned engine with rear sprocket. Also mounted brake calipers, exhaust, intake, Mikuni carb, fuel line, etc.

I replaced the 95 main jet with a 120 before I mounted the carb. Set the airbleed screw at 2 turns out (2X360 degrees), put gas in the tank, put the enrichment on and started the engine. It took me a couple of pulls, but it fired! Some small adjustments done to raise idle rpm. As there is no throttle cable attached, yet I used a blade screwdriver to gently give throttle. The torque converter seems to function, but we'll see what happens with that when it's connected with a chain and under load.

Here's a video of the engine running a bit to high on idle.

"Stay tuned"
 
#60
Hello,
Yesterday evening I connected all brakes en throttle cable of General Lee minibike and made a chain to length and mounted it.
Time to ride it!
It started first pull. Good so far...
This torque converter really hooksup compared to a clutch.
I rode it a couple of times down the street WOT untill it made a strange sound and stopped running. Didn't start anymore...
As it was already to late to work on it, I found out today I broke a rocker of the exhaust valve. Standard rocker.
Not sure why it broke. I have 18lbs springs installed. That should not be the problem I guess?!
 

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