Anything Goes! Build-from-scratch Dutch minibike 4.0

Build from scratch Dutch minibike

  • yes

    Votes: 19 95.0%
  • No

    Votes: 1 5.0%

  • Total voters
    20
  • Poll closed .

Li'l Popeye

Well-Known Member
#1
This years entry will be another minibike.
Again a project for me and my 18yo daughter.
I really like the 2 minibikes that we've build in 2019 OldMiniBikes build off, and wanted to build another one, to add to the collection.
So; here it goes...

This Honda GX 160 engine will be used. I purchased it a couple of years ago and it has been in use since 2000-2005.
It'll be slightly rebuild.
  • Governor will be removed.
  • Charging coils will be removed.
  • ARC billet rod.
  • 31110-Z1V-810 aluminium flywheel.
  • Increase compression ratio with a thin head gasket.
  • Homemade open header (with small muffler).
  • Mikuni carb bolted to homemade intake.
The minibike will get a TAV-2 30 series Chinese torque converter, which will get a homemade sprocket to fit the #219 chain, that we'll be using.
The torque converter is already shipped from China and it should arrive within 3 weeks from now.

First I'll make some small improvements to my 3-D drawings of the minibike. That should help the building proces even more.
 

Steve73

Well-Known Member
#2
Should turn out great for ya. Paint some tulips on the mini once it’s done and ride it wearing your klompens. That would be hoot. Anxious to see how it all turns out!
 

Li'l Popeye

Well-Known Member
#4
Should turn out great for ya. Paint some tulips on the mini once it’s done and ride it wearing your klompens. That would be hoot. Anxious to see how it all turns out!
"klompens"... For the entry pic I thought about using Dutch wooden shoes, but as we don't have them, I wasn't able to do so. It's "klompen" btw. I might buy some to ride the minibike, once it's done.
Have you seen what they did last year? Mad skills!
Thank you.
 

Li'l Popeye

Well-Known Member
#8
Hello,
As I said in the first post, the torque converter should arrive within 3 weeks from then, well it didn't and I got a refund. I have ordered one again and some time later, the tracking of the first ordered one showed that it arrived in the destination country (Netherlands). So I might end up with a couple of torque converters. I will just wait and see what happens.

It's been quiet here, but last week we started working on the engine.

The GX160 engine is completely taken apart and cleaned, as it was very dirty.
It has a stock flat piston and a 18CC cylinderhead. Compression ratio will be increased a bit with replacing the standard thick head gasket with a thin metal head gasket.


Valve train parts after years of service and hopefully many more years to come. 18 Lbs springs will be installed, that will help prevent floating valves at higher rpm's.


No expensive fancy studs, but cheap ordinary studs installed. If the engine will be opened and closed a lot in the future, this will help to save the threads in the aluminium engine block.
The oilsensor and governor are taken out and the governor shaft is cut in half and used to block the top hole. The oilsensor hole is blocked with a piece of metal rod.
Also notice the rust in the cylinder (darker spots); we have honed it a bit and it feels good to the touch. So we'll use it this way.


The inlet valve seat was a bit damaged and as I don't have a valve seat cutter, I tried to fix it this way. I welded a piece of metal rod to a used countersink drill and turned it down in the lathe to fit in the valve guide. It seems to have worked ok.


Some valve lapping later... Checking for valve leaks with the use of cleaning fluid poured in the combustion chamber.


This is the welding-jig for the frame that was made last year.
And some new tubes for the frame. Sized 22x3mm, which comes closest to your 7/8"tube. The wallthickness (3mm=0,118") might be to big for the application, but the little extra weight brings a lot of strengthness and durability.

Engine will be assembled soon and hopefully a couple of torque converters will show up...
 

Li'l Popeye

Well-Known Member
#9
The engine has been partly assembled.


The stock piston is being used again, but pistonrings have been replaced with new ones (genuine Honda). The ring gaps are now within service limits again.
The stock rod has been replaced with an ARC billet rod.


A new aftermarket crankshaft has replaced the stock crankshaft as the stock one gave to much clearance with the new rod.


Connecting rod and crankshaft together.


Engine side cover mounted. The bolts in oilfill holes will be machined to replace the stock plastic plugs.


It doesn't look new, but will run better as new. Hopefully...


Measuring some things. As far as my calculations go, compression ratio will be close to 9,6:1. Just by replacing stock headgasket with a thin head gasket.
 

Li'l Popeye

Well-Known Member
#10
Still not building the minibike frame, but we're getting closer each time. Parts are being gathered, slowly.
Meanwhile my daughter has set up an Instagram page/account about the minibike. I don't have Instagram, but for those who do; here's the link:
https://www.instagram.com/lilpopeye3/.
The number "3" in the end, was the starting number of our tractorpulling tractor called "Popeye".
I thought it would be nice to call this minibike "Li'l Popeye".

Some steel parts for the minibike have been lasercut. Not all, just the 8mm thick parts, for now.


The 8mm thick steel parts being lasercut at work.


This is the 8mm set for 1 minibike. The parts will need some machining done to them.
On the left: the sprocket carrier for the rearaxle assembly.
In the middle: 2 wheel carriers for both front- and rear axle assemblies.
In the top right corner: these 2 pcs will be welded in the frame and the rear axle assembly will be bolted between them.
In the bottom right corner: these 2 pcs will be welded in the fork tubes and the front axle assembly will be bolted between them.


The first ordered torque converters haven't arrived, but I got a refund for them. So I ordered a new one (from a diffrent seller) and it arrived within a week. I was very pleased with the price and the quick shipping, so I ordered 4 more from this seller.


The extra 4 ordered torque converters also arrived within a week. They're not needed for the minibike, but maybe I can make some profit out of them by selling them locally. And otherwise I can use them for other projects. The torque converters are very nice and firmly packed, which is way different then the torque converters I got a year ago.


Also arrived is a new tachometer with a digital speedometer and other indicators build in. It was around $20,- shipped. I will have to find out if it will work with the GX160 ignition. It needs a 12V (8-18V) power source. A small battery will be no problem to mount to the minibike. If I don't get it to work or dialed in, at least I tried. If I get it to work it's a nice addition.
I rather have a bolted down speedometer over an app on my smartphone (how to bolt down a smartphone to a minibike). And it's also a tachometer. It came with 3 small magnets and a speed sensor.

For the gas tank I have found another filler neck and cap as the gas tanks I made for previous minibikes. These new ones have a better price, but might also have other dimensions. So I will have to order them, measure them and addapt my drawings to them. In order to get the right stainless steel parts lasercut for the new gastank.
 

Li'l Popeye

Well-Known Member
#11
A quick update of what has been going on.
To build a minibike frame I have a manual tube bender. It's a Cowley HPB-40 and looks like a JD2 model 3.


Some time ago I had to bend several tubes for work ($$$). This helps with buying parts for the minibike.


Several tubes bend. These are 25x2.5mm stainless tubes. They were hard to bend and gave a lot of spring back.
And I have seen a picture of a model 32 bender, which has a ratchet to prevent spring back. So that was what I needed and was going to make for my bender.


I had to cut a piece of metal with the saw, but the cooling pump didn't work. !@#$%


The cooling pump was stuck and full of dirt, after all these years. So I had to fix this first. I think the oil/water mixture was to rich.


I cleaned the coolingpump and loosened it up.


I also cleaned the cooling fluid tank and filled it with new cooling fluid. This time with 1:80 oil/water mixture.


Saw cleaned and functioning again.


Drilled holes in the piece of metal, that will be the ratchet.


With a grinder the ratchet was shaped.


Piece of tube welded to the ratchet at the correct position. Otherwise it will not function.


Testing the ratchet and I had to make some small adjustments with the grinder.


This functions great! Why didn't I make this earlier?! Springback is now between 0,5-1 degree. Without the ratchet it was 3-5 degrees (depending on material).

Here's a video:
>>>Video of tube bender with ratchet<<<
Nothing about minibike building in this post, but maintenance of tools is also needed.
 

Li'l Popeye

Well-Known Member
#12
Some parts for the minibike have arrived.
I have made a list of parts that go into building this minibike, I checked what I had in stock and ordered what I came short of.


Some parts (like seat, handlebars, grips, cable hardware) are the same as my previous minibikes.
The bearings have another dimension, as I am going to make minor changes to the axle setups.
For this minibike I'll be using thick wall tubes as axles in the wheels and neck.
I ran out of the fillernecks and gascaps I used in my previous minibikes, so I had to order new ones. This time I found some in Netherlands, but it didn't have any dimensions. The price was good (€8,96 for cap and fillerneck), so I ordered. It turns out, it has the same dimensions.
Tommorow a 85T rear sprocket for #219 chain should arrive.
Other parts, like calipers, carburator and angled air filter are on their way from China. I have ordered them at Aliexpress. They should arrive somewhere at the end of this month or somewhere in April.

As long as the government doesn't "make" a complete lockdown (regarding the Corona-crisis), things can get started. At the moment there's a partial lockdown; all Dutch schools are closed. Bars, restaurants, all public places are closed. All events have been cancelled. The first Dutch F1 grand prix, since 1985 has been cancelled.
People are advised to work from home, as far as that's possible. So we'll have to see how all this turns out. It might end up with a complete lockdown.
Positive tested people is growing each day with about 25-30%.

Stay healthy and stay tuned...
 

Li'l Popeye

Well-Known Member
#14
Popeye, my coolant pump for the saw does the same thing if I forget to run it a few minutes every week. The coolant turns into slime and gristle if it sits stagnant for too long.
That's what I thought. The saw isn't used every week and the coolant mixture was way to rich.
 

Li'l Popeye

Well-Known Member
#16
Latest news (as of yesterday); here in Netherlands there's a "partial lockdown" until june 1st. It's not a lockdown like in France, Italy, Belgium. We are allowed to go to work and to go outside alone, if we want to. We are not allowed to gather in groups of 3 or more. Always keep 1,5 mtr distance to others. And lot of other regulations.
This can change into a complete lockdown if government feels it it needs to do so. If people do not listen.
So, at the moment, I'm still able to go to the workshop, which is about 10 miles from here.
 

brown boonie

JUST REMEMBER-EXPECT IT WHEN YOU LEAST EXPECT IT!
#17
Latest news (as of yesterday); here in Netherlands there's a "partial lockdown" until june 1st. It's not a lockdown like in France, Italy, Belgium. We are allowed to go to work and to go outside alone, if we want to. We are not allowed to gather in groups of 3 or more. Always keep 1,5 mtr distance to others. And lot of other regulations.
This can change into a complete lockdown if government feels it it needs to do so. If people do not listen.
So, at the moment, I'm still able to go to the workshop, which is about 10 miles from here.
here in the NY STATE, just essential workers allowed to go to work, no large groups, all restaurants are take out only with pre call and a time for pick up with most. told to keep at 6 feet (2 meters) away from each other when possible. grocery stores are getting back to semi normal at this point. lots of people working from home also. keep safe and keep mini biking.
 

Li'l Popeye

Well-Known Member
#18
here in the NY STATE, just essential workers allowed to go to work, no large groups, all restaurants are take out only with pre call and a time for pick up with most. told to keep at 6 feet (2 meters) away from each other when possible. grocery stores are getting back to semi normal at this point. lots of people working from home also. keep safe and keep mini biking.
Ok. Here it's recommended to work at home, if possible. For me (welding) that's not possible. It's not an essential job, but we are still allowed to go to work.
 
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