# Firearms and Shooting > Projects and Home Builds >  2-Stroketastic!!!

## kimjon

At high school there was kid who had an"American pie" moment with a Swedish exchange student...poor guy saw out his days at high school with the nickname "2-stroke"... sorry funny story that always comes to mind if someone says "2-stroke".

Anyway, I've always had an affinity for proper gas engine 2-stroke engines. My parents weren't rich, so my love affair with these engines wasn't realised until I had an income of my own.

My first purchase was a MX bike. 250cc of craziness!

Then a 12A rotary RX7... technically a "2-stroke". Cheap speed, fun times! And although I'm more into my V8's now, I'm not afraid to admit the odd rotary catches my attention, and makes me smile.

Next was a Kt100 gokart. You'd wonder how a 100cc engine could produce so much power...actually I still do wonder how - absolutely incredible!

Then came gopeds. I have 5 goped sports, all in various extremes from near stock to insanity! This is my dream build...this bad boy will be nuttier than squirrel shit! I just finished the motor today, its a hybrid...I won't bore you with details, but lets just say it will be fast :Have A Nice Day: 





The expansion chamber is a work of art!

Anyway, the above is the result of the dangers of the internet and a paypal account :Wink: ... let this be a warning!

Oh and while my wife and three kids are away on school holidays...hell yes this gives me the right to build a gas engine on the kitchen table!

Kj

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## Sideshow

> At high school there was kid who had an"American pie" moment with a Swedish exchange student...poor guy saw out his days at high school with the nickname "2-stroke"... sorry funny story that always comes to mind if someone says "2-stroke".
> 
> Anyway, I've always had an affinity for proper gas engine 2-stroke engines. My parents weren't rich, so my love affair with these engines wasn't realised until I had an income of my own.
> 
> My first purchase was a MX bike. 250cc of craziness!
> 
> Then a 12A rotary RX7... technically a "2-stroke". Cheap speed, fun times! And although I'm more into my V8's now, I'm not afraid to admit the odd rotary catches my attention, and makes me smile.
> 
> Next was a Kt100 gokart. You'd wonder how a 100cc engine could produce so much power...actually I still do wonder how - absolutely incredible!
> ...


And use her best white towels :ORLY:  :Thumbsup:  man you going to be in the naughty books  :ORLY:

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## veitnamcam

You must bore us with details I insist! 

I too love the twostroke and their infinite tune-ability

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## deadidick

I hope you been keeping up with the house work and washing and better been changing yr undies @kimjon while the missus and kids are away. 
Very impressive looking 2 stroke there, have you chromed the expansion chamber? 
Stick a video up when you fire that bad boy up for us all to see.
 :Omg:

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## kimjon

> You must bore us with details I insist! 
> 
> I too love the twostroke and their infinite tune-ability


Started off as an already high spec little engine at 22.5cc.

It's a hybrid, meaning the bottom end is a zenoah 230rc, the cylinder is a Chinese clone that's had the head machined off. The cylinder head had 4 transfer ports...these have been port mapped and ever so slightly ported to change the port timing a tiny bit. The head has been replaced with a hemispherical dome head specially calculated to the right volume to run on 95 octane gas/oil mix. The new cc rating is now 28.9cc due to larger bore of new top end. The flywheel has been lightened. The timing has been advanced. Massive dominator tuned expansion chamber. Huge walbro carburetor. Velocity stack. K&N filter. 0.7" drive spindle. Third bearing support added. Chrome fan cover and pull start.



Yes...lost the plot...but everyone needs a hobby eh :Grin:

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## deadidick

So what you going to put it in? Skateboard, bucket racer? Looks mean.

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## kimjon

> So what you going to put it in? Skateboard, bucket racer? Looks mean.


You'll have to use your imagination a little at this stage. 



But this pile of "parts" will be made into a goped roller...the motor will go on it. Will be badass!

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## deadidick

Just googled it, yep that is going to be nuts. Be sure to show us the final result. :Thumbsup:

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## Maca49

How old are you? I've missed something in my life! Am I'm to old to catch up? I'm pretty good at two stroke  :Grin:

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## kimjon

Knocking on 40yrs old...still 18 at heart :Thumbsup:

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## Sideshow

:O O:

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## Maca49

Knocking on 40 FFS 26 yrs ago I thought that was getting old! Just outa nappies now, where did 26 years go ?

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## Maca49

> Started off as an already high spec little engine at 22.5cc.
> 
> It's a hybrid, meaning the bottom end is a zenoah 230rc, the cylinder is a Chinese clone that's had the head machined off. The cylinder head had 4 transfer ports...these have been port mapped and ever so slightly ported to change the port timing a tiny bit. The head has been replaced with a hemispherical dome head specially calculated to the right volume to run on 95 octane gas/oil mix. The new cc rating is now 28.9cc due to larger bore of new top end. The flywheel has been lightened. The timing has been advanced. Massive dominator tuned expansion chamber. Huge walbro carburetor. Velocity stack. K&N filter. 0.7" drive spindle. Third bearing support added. Chrome fan cover and pull start.
> 
> 
> 
> Yes...lost the plot...but everyone needs a hobby eh


You've got talent! :Thumbsup:

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## 300CALMAN

Awesome I love 2 Strokes!!!

You have to post a video of it going

My tally so far (now all gone):

GT200 Suzuki
S3 400 Kawasaki
H1 500 Kawasaki  :Psychotic: 
RZ 350 Yamaha  :Zomg: 

various outboards and lawnmowers :ORLY:

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## 7mmsaum

Idiot tries 2 stroke drifts on bike 

Bloody made me laugh

http://youtu.be/lVdKxqJ6JzU

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## JoshC

If you like that, you might appreciate old Ronnie Mac  :XD: 

https://www.youtube.com/watch?v=tCI62cw7_zM

https://www.youtube.com/watch?v=I8b30u1lKGw

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## kimjon

The frame I picked up didn't quite live up to the trademe description...but beggars can't be choosers. These aren't that easy to come across in NZ.

So rather than dwell on negatives, I welded up the broken bits, and stress fractures. 




Next came a trial fit, a few extra holes were needed. And with the magic of a mig welder and a grinder...a few holes disappeared!




Next will be to send the frame off to get some type of coating. Toying with ideas, but thinking out loud something like HPC coating?

I've got to figure out forks and some form of head set arrangement to hold it in place. Handle bars will then be the next headache. But I like a project and an idea (cheap idea) will come to mine :Have A Nice Day: 

Kj

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## Tommy

Powdercoat it, add some clamps and a Renthal bar hahaha trick as  :Grin:

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## longrange308

> Awesome I love 2 Strokes!!!
> 
> You have to post a video of it going
> 
> My tally so far (now all gone):
> 
> GT200 Suzuki
> S3 400 Kawasaki
> H1 500 Kawasaki 
> ...



You need to add a rotary to that list

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## 300CALMAN

> You need to add a rotary to that list


 @longrange308 you don't even know me and you want to kill me?
Had a good go at that once on a motorbike. Drive slow 4x4s and family cars now, call me a pussy but it keeps me above ground. Still temped to buy a nice slow motorbike like a firestorm or TRX850 or maybe a 250 2 stroke trail bike  :Grin:

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## kimjon

Frame all finished. Found more stress cracks, drilled holes in the ends of the cracks (old trick, logic being that a crack will stop at a hole) then ground out a v into the crack and welded it all back again. Finally ground the welds back flush and you'd never know any different. 


I took it all back to bear metal, and dropped it off at local car painters for a coat of etch primer and some 2 pak paint. I looked at other options briefly...then thought paint is as good as anything else, and secondly it is just a big kids scooter after all, not a show car.

Kj

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## 300CALMAN

> RD400 ,,, perhaps ?


Definitely, with the coffin gas tank and flat seat... the one that doesn't hold your butt on the bike as you accelerate wildly down the street!

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## 300CALMAN

> Frame all finished. Found more stress cracks, drilled holes in the ends of the cracks (old trick, logic being that a crack will stop at a hole) then ground out a v into the crack and welded it all back again. Finally ground the welds back flush and you'd never know any different. 
> 
> 
> I took it all back to bear metal, and dropped it off at local car painters for a coat of etch primer and some 2 pak paint. I looked at other options briefly...then thought paint is as good as anything else, and secondly it is just a big kids scooter after all, not a show car.
> 
> Kj


 @kimjon stop teasing us your photos don't work, says you image was linked incorrectly.

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## kimjon

> @kimjon stop teasing us your photos don't work, says you image was linked incorrectly.


Hmmm, I can see them. But I'm viewing it on a phone. Wonder what's going wrong?

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## kimjon

I milled up this plate too. The rear fender was snapped of the frame, I could have replaced it like for like...but I had this idea in my head for something a little different.


I think I will look the part once final assembly takes place.

Kj

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## sako75

How is the mill going?

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## kimjon

> How is the mill going?


Awesome! It completes me :Grin:

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## rambo rem700

awesome stuff. love my 2 bangers, had 2x rgv250, one race one road  2x rx7s, cr125s,250s kx500 the list goes on lol.
cant wait to see it finished

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## Bill999

just mount it on a surf board like those thai kids do and clock 140km/hr

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## kimjon

Started the motor for the first time today. It roared into life with relative ease. I soon realised it was starving for air, so tore it down again looking for reasons why. Didn't take long to see why, the velocity stack had an internal diameter of 15.4mm, but the carb internal diameter is 19mm!

I bored out the inside, then while it was dialed true in the lathe, thought I'd contour the shape to aid flow. Pretty happy with how it turned out.

Kj

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## Smiddy

Kimjon - you the man 


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## Sideshow

:O O: Has she found that towel yet? :Thumbsup:

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## kimjon

Okay, things are happening fast with this one.

Here's a before pic of what I was dealing with:

And after:


Chrome "bothy" forks


DDM Racing third bearing support




My milled aluminum rear fender:



Tank, with billet DDM cap all installed with my own lathe turned aluminium spacers.




That's it for now. I've ordered a few parts off ebay that I'm waiting on to complete this project with. I'm going to machine/weld up the handle bars this week while waiting on ebay parts to arrive. I'm pretty happy with the silver...I've been known to say unkind words about silver in the past...basically it does suck as a paint colour, but for this project I think it compliments the chrome nicely without being overly tacky? I'm going to put some blue parts in the mix too break it up a little... all will be explained later. :Grin: 

Kj

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## sometimes

cool making honey out of dog shit :Cool:

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## stug

Needs a red racing stripe, because we all know red is faster :Thumbsup:

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## kimjon

> Needs a red racing stripe, because we all know red is faster


Red is faster Stu - it's a well known fact :Have A Nice Day:

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## 300CALMAN

Awesome I can see the pics now... Yes red is definitely faster and sexier but it's usually Italian and unreliable  :Psmiley:

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## Micky Duck

your nuckin futs Batman...cant wait to see final result.

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## 300CALMAN

> . Italians are ok ..... just that there seems to be a disproportional amount of penis fingered wankers owning them ..............I have several


 @hamsav never said I didn't like them but they do have an affinity for the workshop.

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## 300CALMAN

> yeah ya gotta wonder at the Ferrari add that sez  " 11000kms , new clutch , new cam belts .... "   , especially when you know that's an "engine out" job . Desmo valve gear has an undeserved rep for being expensive , hi maintenance ( having said that most workshops will gouge as much as they can on this one )..... old story  the longer and closer you spent at the red line the more often you have  to adjust clearances . I enjoy working on them as much as riding them


Fair comments. Never owned one only jap bikes so no real personal ownership experience except for riding a couple of 900SS Dukes. Great fun but I found them a little cramped for my large frame, strange they must have the foot pegs close to the seat. They did seem to spend a fair bit of time being fixed but as you say "Time on the Red Line = Garage Time"  :Grin:  

Going back to two strokes Vespers and Lambretta seemed to go ok.

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## kimjon

Had a cool idea for a kickstand. The originals had a large two sided loop. Hard to explain, but irrelevant as I didn't have one anyway. So I welded this up:



And lean it to the right and it automatically "springs" up under tension. The spring holds it out of the way...pretty trick!


It's the devil in the detail :Have A Nice Day: 

Kj

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## kimjon

MKII model:


I had to make it clear the part where the deck bolts on, as I forgot about the rubber isolator. Looks a bit more shapely now with a few more curves :Grin:

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## sometimes

just the thing for a crate day when its finished that will sort the men from the boys after a dozen big bottles  :Grin:

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## Sideshow

> MKII model:
> 
> 
> I had to make it clear the part where the deck bolts on, as I forgot about the rubber isolator. Looks a bit more shapely now with a few more curves


Looking good.....but did your arms shrink in the wash with that towel? Because those are some bloody short handle bars :Thumbsup:

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## kimjon

I'm skipping a lot of the detail in this thread. Things take hours of time to make and involve countless steps in their production...but that would be tedious to read through. The motor alone has about 30 hours of my time for example.

But this is a Labour of love, I'm doing it because the inner child in me always wanted one like this...and now I'm doing something about it :Wink: 




I made these handle bars up. The original bars were fucked! They used OD28mm x 0.8mm wall aluminium - I guess to save weight, but they are very fragile. I managed I find some 3mm wall thickness aluminum, but in OD30mm. The bottom clamp is for a mountain bike and is ID32mm and the top bar clamp is a goped performance part with an ID of 28mm...problem!!! But after some head scratching I made a shim to increase the bottom of the pole to 32mm and I turned down the top of the pole to 28mm. Result!

Kj

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## veitnamcam

How does it drive the tire? Friction drive on the tread? direct drive? chain an sprokets? gears?

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## kimjon

> How does it drive the tire? Friction drive on the tread? direct drive? chain an sprokets? gears?


It has a friction drive. Basically out of the motor, directly connected to the crank is what looks like the knurled handle of a socket wrench. The drive spindle is about 19mm in diameter and the wheel is roughly 190mm in diameter...so giving it roughly a 10:1 gear ratio. 

This knurled drive is a direct drive...i.e. no clutch, so when the motor is going, so are you. It's single speed, no gears. The engine should top out at 19,000 rpm (give or take). I haven't done the math, but it will do about 40-50km/h. Doesn't sound fast, but it will get to top speed pretty quickly!

As the tire wears, you can move the tire up to meet the motor which is in a fixed position. 

Very simple design. It does have a few negatives, but overall its perfect for this application.

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## veitnamcam

> It has a friction drive. Basically out of the motor, directly connected to the crank is what looks like the knurled handle of a socket wrench. The drive spindle is about 19mm in diameter and the wheel is roughly 190mm in diameter...so giving it roughly a 10:1 gear ratio. 
> 
> This knurled drive is a direct drive...i.e. no clutch, so when the motor is going, so are you. It's single speed, no gears. The engine should top out at 19,000 rpm (give or take). I haven't done the math, but it will do about 40-50km/h. Doesn't sound fast, but it will get to top speed pretty quickly!
> 
> As the tire wears, you can move the tire up to meet the motor which is in a fixed position. 
> 
> Very simple design. It does have a few negatives, but overall its perfect for this application.


Ah so a smart(or silly) man with a lathe could gear it up to take advantage of the extra power :Wink:  :Wink:

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## 300CALMAN

Careful we don't want any attempts at the Darwin awards  :O O: 

50km/h will seem like warp 3 when you are on that tiny thing, Those small wheels wont stop too fast either!

BTW I love it already, it looks like all motor and expansion chamber.

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## kimjon

Yes VC you're on to it, but at the cost of acceleration. Standard spindle size is 0.6", because of the extra power I'm hoping/banking on getting from my porting and other mods, I've gone to 0.75" spindle diameter. This will hopefully raise top end speed from about 30-40kph to about the expected 40-50kph I'm going for. 

Hopefully it doesn't bog too much at the low end due to the taller gear ratio...but only time will tell? :Grin:

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## deadidick

Looking sick Kimjon, at 50kmph I'd say you are going to scare hrs elf and any citizens nearby shitless when you scream past them on the footpath. 
You are going to have to post a video. 
Maybe down the greyhound track riding it dressed as a rabbit?

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## puku

I think I need one! 

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## specweapon

But can it drift?

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## kimjon

My parts arrived from the U.S. today. Ebay rocks!

Anyway, just waiting on one last package, some fancy billet clamps, but for now two $0.02 cable ties will do just fine.

So as they say..."that's a wrap!" The photos don't do it justice, I spent hours polishing all the aluminium to look like chrome, and every detail has had an obsessive amount of attention. 

My wife is back from her holiday, I can see her eyes glaze over as soon as I mention this project...I'm going to be banned from talking about it around her soon, I can feel it :Grin: 








So as silly a project this is, I'm pretty happy with what I've made. Now is time to ride it, well maybe tomorrow...it's dark outside and raining right now... :Grin: 

Kj

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## veitnamcam

And after the test ride you can order the Nos kit  :Thumbsup:

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## 223nut

Rain could make it really imteresting!!

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## deadidick

Fuck yea! Looks bad arse all right.

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## kimjon

Okay, yeah/nah...won't be in a hurry to fit nitrous oxide to it...pretty fast alright, definitely not disappointed in its performance that's for sure.

This thing is a beast! Wants to run fast, does bog a little from its idle, but from low/mid range upwards the power band is massive. If you keep it out of absolute idle, i.e. low/mid upwards there is power to burn with very quick throttle response. Best I can describe the feeling is like running any performance car/bike as if stuck in second gear.

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## Nibblet

So gopro footage?

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## veitnamcam

> Okay, yeah/nah...won't be in a hurry to fit nitrous oxide to it...pretty fast alright, definitely not disappointed in its performance that's for sure.
> 
> This thing is a beast! Wants to run fast, does bog a little from its idle, but from low/mid range upwards the power band is massive. If you keep it out of absolute idle, i.e. low/mid upwards there is power to burn with very quick throttle response. Best I can describe the feeling is like running any performance car/bike as if stuck in second gear.


Bigger pinion on its way then ay   

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## kimjon

I'll have to figure out a nasty way to film and upload it, probably with my phone.

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## MSL

Bring it round the workshop on Monday night and I'll film you banging down Ellis street

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## Beaker

> I'll have to figure out a nasty way to film and upload it, probably with my phone.


Chest mount for the phone.....

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## Beaker

You are a bit of a prick though (never met), as you have planted the thought that I may beable to make one of these things. As they look like HUGE fun.....  :Have A Nice Day:  

Another project! Maybe a motorised chilly bin, or a lazy boy, or a mobility scooter, or a wheel chair, or or or ....  :Have A Nice Day:

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## 7mmsaum

Belt drive a chainsaw engine to the back wheel, epic fun

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## deadidick

Get someone to film ya while they are giving chase in a car or motorbike or something, put a go pro on a selfie stick up high an in front as well so we can see the look of joy on your mug, as you fang it down the road. 
Maybe you should have applied for funding from Broadcasting NZ at the start, made a mad doco, funding might have paid for it?

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## kimjon

> You are a bit of a prick though (never met), as you have planted the thought that I may beable to make one of these things. As they look like HUGE fun.....  
> 
> Another project! Maybe a motorised chilly bin, or a lazy boy, or a mobility scooter, or a wheel chair, or or or ....


Is an easy project. I made one from a weedwhacker engine last year. It was functional and worked...but it was nicknamed the "slowped".


Was pretty easy, hardest part was machining an adapter plate to hold the motor to the frame. But this could have been avoided by a better choice of motor (I had to run this one on the opposite side as it ran backwards compared to normal engines).

Kj

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## kimjon

"America - Fuck yeah!" Yes, the puppets from that movie Team America said it best. Ignoring Donald Trump, a history of keeping slaves and the KKK and all the other negatives...there is some seriously cool shit made there. Think of most really cool stuff like AR15's, Harleys, Chevrolet cars, monster trucks, motor cross etc etc... America, Fuck yeah!

And from the land of the free arrived yet another awesome little package. It contained the nicest set of cable clamps money can buy...and after a quick rebore from 28mm out to 30mm to suit my home made pole, they looked ever so awesome on my goped:









So that's it. All done!

Kj

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## Ryan_Songhurst

we want video

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## Sideshow

All you need to mount on that bad boy now is a big ass rifle rack  :ORLY:  :Thumbsup:

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## deepsouthaussie

A mate back home had something similar but more trike style and an esky for the seat.. He'd take it every getting right shitfaced as he went about..
Ended up getting booked by the cops. Haha He had a winge and the media listened a ran a story on the local news. Was funny as..

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