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7/11/19 6:32 p.m.

This looks pretty. Great project!

Chappers Reader
7/15/19 10:13 a.m.

In reply to RichardUrena :

Thanks! It's been fun, due to the budget constraint, keeping cost down by reusing material etc..

I worked on the seat frame, i reused the original handlebars.

Chappers Reader
7/15/19 10:23 a.m.

Used some RM250 footpegs and a CX500 side stand and chopped off some superfluous brackets. 




Chappers Reader
7/15/19 10:29 a.m.

Got 2/3rds of the mounts done for the fuel tank and also cleaned out the rust with evapo-rust, that stuff works really well by the way!

Then wheeled it outside to clean the garage a bit.


Still to do:

Rear fuel tank mount

Better headlight mount (cheap brackets that came with the cheap headlight bucket are terrible)

Tail light and rear fender mount/frame 

Finish off seat mount (combined with rear tank mount)

Some sort of high mounted muffler

Skid plate

Mount front fender

Battery and wiring cover 

Intake snorkel and filter



Strip it all down and paint it.


Color scheme undecided..


Justjim75 HalfDork
7/16/19 12:36 a.m.

You're making that look fun, two thumbs up.  Giving me the push i need to start a similar idea ive had for way too long.

Daylan C
Daylan C UberDork
7/16/19 4:44 a.m.
Chappers said:
akamcfly said:

Do you have any other cx500 parts? laugh

You could talk to gearheadE30 on here, he’s doing a scramblerized CX500 a has a fair few spare parts...

That dude has a bunch of cool antics going on in a not very big space.

akamcfly Dork
7/16/19 3:34 p.m.
Daylan C said:

That dude has a bunch of cool antics going on in a not very big space.

I saw his entry to this build-a-bike competition. devil

As for space, he has a little more now that I bought some spare parts from him.

Chappers Reader
7/17/19 7:51 a.m.

In reply to akamcfly :

Oh yes, his bike is kickass!

And he knows how to ride! 

Chappers Reader
7/17/19 8:06 a.m.

I managed to get hold of a HMF exhaust system pretty cheap as the seller didn’t know what bike it was designed for. Its nice and light, thin gauge stainless. Came with 2 header pipes so I’ve got extra bends. 

Thinking high mounted, would like to have it horizontal ideally, but the frame sticks out too far and the muffler looked silly. 

Still looks a little too stuck out at the front,  but I’ll do some cutting and it’ll work. 

Bigger bore 

Not too far out from the stock header. 

Would hang too low like this, so I’ll either trim that first straight section off, or kick it forwards into the open space ahead of the engine! 

I’ll make all the cuts and tack weld it, then have a buddy Tig weld it. 


Also I took it for a ride around the yard yesterday, it ran dog slow and would bog when throttle was applied. Someone advised me that as I’m running open Intake and no muffler I should richen it up. So I dropped one groove on the needle and now it flies! Lots of fun.

Chappers Reader
7/18/19 8:10 a.m.

A couple more jobs off the list. 

Rear fender mount. 

Made from the passenger foot pegs brackets. 

The cheap bike eBay headlight came with a terrible bracket, wouldn’t clamp on the forks properly. So I chopped the clamps off the original scooter forks as they are the same diameter. 

And welded the headlight bracket on to them. 

Nice and solid! 


I had a brain fart with the exhaust though, as I wanted to mount the muffler high up on the frame, but the engine on this moves with the swing arm assembly. 

So I either need a flex joint in the exhaust (not any favorite plan)

or make a mount off the swing arm to mount the muffler higher up, but the mount may be too tall and unwieldy. 

We’ll see...


Chappers Reader
7/19/19 10:09 a.m.

Made a bracket off the swing arm to mount the muffler. 

There is 2.5” of suspension travel, so I had to lower the muffler height by that much so the bracket doesn’t make contact with the frame. 

Then cut up the header pipe and MiG welded this lovely thin gauge stainless pipe with plain old mild steel wire. Haha

Proud of myself that I didn’t make a complete balls up of it. 

Then tried to sit on the bike and realized that even my small size 9s would hit the header pipe, damn. 


Chappers Reader
7/22/19 8:29 a.m.

Bought a rather large sheet of 12ga T6 

made a tail light bracket

I’m not planning on turn signals

I also got a ‘performance’ CDI and coil, and a jet kit. Bit of playing around with the carb and I’ve settled on 120 main jet with the stock needle height.

I also ordered a set of lighter roller weights for the variator. 

Decided to chop the right side foot peg off and move it forwards 4” so I can actually put my foot on the peg without risk of melting my shoe on the header. 

It’s odd having the foot pegs staggered like this but I’ll get used to it...

jfryjfry Dork
7/23/19 2:30 a.m.

And you can’t move the left one forward because....???

Lof8 Dork
7/23/19 7:19 a.m.

This is looking really cool. I bet a lot of people are going to look at this and think, “wtf?! It’s got no engine!”

Chappers Reader
7/23/19 8:32 a.m.

In reply to jfryjfry :

Haha, I've got one leg longer than the other of course! 

Chappers Reader
7/23/19 8:49 a.m.

In reply to Lof8 :

Thanks. Hey now, it's just mid engined! The gaping hole is my "Frunk". 

I did a "top speed" run last night, erm quite disappointing, only managed 43 mph indicated on my Garmin GPS.

Looked like the front brake rotor was binding in the caliper (a result of my very poor DIY machining job). Zip tied the caliper out the way and managed 46mph - still not good.

These 16" wheeled 150cc scooters are supposed to do 60mph. The variator weights are 12g, I'd previously ordered some 10g weights to try, (not arrived yet)  but I think that will make top speed worse, but its very easy to test. 

Also sounded like it wasn't reaching a very high rpm, so I've ordered an induction style tach.

Going to my buddy's machine shop tonight to true up the rotor. 

Chappers Reader
7/24/19 10:36 a.m.

Found a way to get this sucker to 60mph! 

Took it to my buddy’s machine shop, we machined the rotor mounts on the wheel and now the front brake doesn’t grab. Wheel rim had 20 thou lateral run out and almost no radial run out! 

You’ll see I also moved the left foot peg forward to match the right side.

variator weights and tach arrive today - so I’ll have test result available tonight. 


akamcfly Dork
7/24/19 4:10 p.m.

The space where an engine usually goes should house a mini bar - not that I encourage the two activities combined.

Chappers Reader
7/24/19 10:12 p.m.


12g weights gives 6600rpm and 46mph

10g weights 7200rpm and 49mph

then took air filter off (just a hunch) and it managed 50mph. 

This is an average of two 1/4 mile runs in either direction. 

The 10g weights feel quicker to accelerate, but I don’t have data to validate that. 

I might try some kind of app to record the speed with my phone. 


Not the boost in speed I was hoping for unfortunately. 

adam525i Reader
7/25/19 11:27 a.m.

Seems like the ugly fairing and slick tires made a decent difference in top end, it looks awesome though.


Chappers Reader
7/25/19 12:22 p.m.

In reply to adam525i :

Yup I think you're correct. 

It dawned on me that I'm only running 15psi in the tires, perfect, for off road!

On my WR250R running 15psi all the time makes no difference to top speed. 

So I'm going to test them aired up tonight.

A "performance" cam arrived today so I'll make one change at a time and publish the results.

Oh here is the video of the 46mph run.


Justjim75 HalfDork
7/25/19 5:18 p.m.

Im enjoying this thread, even tho my version of your project is powered by 24 volts.  I use the Speedview app on road trips and to test top speed of my son's dirtbike and my electric mini bike, just set the yellow circle to Max by pressing and holding and the red arrow points to a gear where youll find settings including clearing max speed.

Its free

minimac UltraDork
7/28/19 11:51 a.m.

Awesome build. Good work and skills!

Chappers Reader
7/29/19 1:00 p.m.

In reply to minimac :

Thanks! Although this is by no means good work, I feel like I've had to cut corners to keep the budget low. So far I think I'm around $600 total cost.

I wish I'd had a bigger capacity scooter as the basis, Piaggio and Aprilia have liquid cooler 250cc models with 16" wheels and 60-70mph top speeds, but they are substantially more expensive than this $100 initial purchase price. Plus if I want to spend $1000 on a bike I probably wouldn't even pick a scooter..


In the pursuit of more speed or more power, I've tried the different roller weighs (only lighter than stock) and I tried jetting the carb, seems to like no more than 120 main jet.

I also tried a "performance" (A12) cam, i say that because there is very little information for these cams, ive not seen a comparison of the power curves on a base engine, only conjecture from people of forums that say their moped/buggy performed better with A9, A12 cam etc..

So I gambled the $25 on this A12 cam, it is heavily reground as I was on the absolute max of the lash adjustment screws. 
The result was absolute zero difference in top speed and slightly reduced acceleration response. 

With the cam I tried running 1/2 the stock 12g roller weights, effectively running 6g, which increased RPM to 9000 and reduced the top speed. So that must be outside of the engine's power band. 

Increasing the carb size from 24 to 30mm could have been an option, but someone YouTube guy tried that already and verified they had no increase in top speed. (saving me wasting $100)

I ordered taller final drive gears, but the company refunded my money as they were out-of-stock, talking to them afterwards it would have been futile anyway as you need more HP to really utilize the gears to get higher top speed. 

Unfortunately I don't think there is any more low hanging fruit to gain more top speed on this engine. The next steps would be spending a few hundred dollars and I don't want to do that on this "cheap bike challenge" build. 

So 50mph top speed it is! 200 miles down to Kentucky is going to feel like a looong way...

Chappers Reader
7/29/19 1:08 p.m.

Well if I can’t go any faster, I may as well look good going slow...

painted the front fender

Heated up and bent some chopping board

3 feet of skid plate! 

Then came apart for tidying up and painting the frame. 

I started making a template for a cover to hide all the gubbins under the seat. 

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