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Sachs Madass Performance upgrades from FastTrails
By: fasttrailsperformance ( 1373Feedback score is 1000 to 4,999)  Top 1000 Reviewer
23 out of 24 people found this guide helpful.

Hello from the staff at fasttrails! We are writing this article to shed some light on what we here at fasttrails have learned about the Tomberlin Sachs Madass scooter (called the AMG Nitro in Canada).  This scooter can be transformed into a capable street scooter with help from Fast Trails Performance.   The stock 50cc is fun, but very slow, so FTP has stepped up to offer the best performance upgrades availible for the Madass

This little scooter is probably the coolest looking scooter around. Unfortunately, in stock form the 50cc version is not a good performer. This is the only scooter that we think looks 'cool' to ride, but when kids on BMX bikes start pedaling past you, you will soon want to increase the horsepower of your madass.

There are many ways to do this. And as the old joke goes, the question "how fast can I make it go?" can be simply answered by "how much do you want to spend?"

There are a few 'stages' you can take your madass to.

1) Stock engine internals, but upgraded Carburetor, Intake, CDI box, and possibly exhaust.

2) Stock engine Big bore kit

3) Replacement engine. Ditching the stock 50cc engine in favor of a manual clutch 125cc engine like the new 125cc Madass, or a Performance 140cc Engine, 150cc engine, 160cc engine and even 172cc Engine with 4 valve head!

Starting with the stock Madass, first thing to do is remove the stock restrictor in the CDI harness. 'De-restricting Sachs Madass' in google will point you to many online resources explaining how to do this simply mod. Not much performance gain, but at least it untaps the full power potential of the little ole' 50cc.

Note: We have not found this restrictor on any Canada versions of the Madass (called the AMG nitro).

The next step to improving the madass is to replace the tiny stock 13mm Mikuni carb and intake. Fast Trails Performance has 18mm mikuni carbs that are the same as the stock one so you can maintain the use of the handlebar operated choke. Carb and intake upgrades are usually good for at least almost 5 MPH or 8Km/hr, with better mid range power. Upgrading the stock exhaust to a big bore exhaust will further improve this gain. Or even 'gutting' the stock exhausts cataylic converter will help a little.

If you want serious increase in power, you need to up the CC's of the stock engine. This can be accomplished by a simple bolt on big bore kit. But it is highly recommended that you get a quality big bore kit which includes a big valve/ big port cylinder head.

The stock madass cylinder head has the same port and valve size as a Honda XR50. VERY Restrictive! So to get any reall gains from an 88cc cylinder piston combo, a performance head really needs to be installed. 75cc kits using the stock head are, in our opinion, not worth the money for the gains provided.

The Sachs madass 88cc big bore kit with race head offered by FastTrails is the best kit availble as it includes some required parts for the madass build. With an 18mm Mikuni carb, FTP 88cc kit and 13T front sprocket, we have seen 45mph or 73km/hr.

The weakness in using the stock madass engine with a big bore kit, is the limitations of the stock Madass Transmission. Many call the fully automatic a '2 speed' when in reality it is a single speed transmission. '1st speed' is when the clutch is slipping, and '2nd speed' is when the clutch is locked up. the manual 4 speed madass is a much better set up for getting speed from your Madass.

The best option is to replace the stock madass engine all together. A few things to note when replacing a stock madass 50cc engine:

1) The madass uses a unique 3 phase stator / alternator in order to supply enough power to all the bikes electrical accesories (lights, horn, signals, starter motor, etc). When replacing the stock engine with a electric start 110cc or 120-125cc engine, the best / cheapest way to simplify your conversion is to re use your Stock 50cc madass Stator and flywheel. With the proper flywheel puller, available at FastTrails, this is a fairly simple task.

If you are replacing your stock electric start engine with a kick start only engine, the best idea is to purchase the FastTrails Exclusive 3 phase stator for kick start engines. If you purchased your Madass engine from FastTrails it will already have this installed. So you simply bolt in the engine and plug it into the stock wiring harness. No splicing of wires, no addition of relays, no dead batteries etc.

If you purchased a kick start only engine elsewhere, it is almost imperative that you contact Fasttrails for one of their kick start only stators for the madass. Attempts to use the 1 phase stator used on chinese engines will result in much frustration and poor results.

2) The next thing to note is that the Sachs madass uses a larger upper motor mount than other engines of this design. If purchased from FastTrails your madass engine kit is a direct bolt in. If purchased elsewhere, you will have to drill or machine the upper motor mount of your engine to fit the stock madass chassis.

3) Any engine over 110cc will really benefit from Gearing and Exhaust upgrades. The stock 50cc madass exhaust is restrictive even to the stock 50cc engine. It will severly limit the output of your 110cc + engine.

4) Gearing: the stock 50cc madass uses a very large 52Tooth rear sprocket with a tiny 12Tooth front sprocket. This super low gearing is required with the low torque of the stock 50cc engine in order to get the bike rolling. Once you increase your torque and HP you will want much higher gearing in order to keep the more powerful engines in the power band.

A 110cc install is fairly straightforward, but most 110cc engines do not use the best cylinder head. A 125cc engine from FastTrails is a much better option as this engine uses the 'big Valve, big port' cylinder head. So it will perform much better than a 110cc engine despite only having 12cc's more.

To simplify the install, most 110 and 120-125cc engines with electric start will need a stator swap. Get a flywheel puller and use the stator and flywheel from your stock 50cc engine.

In our opinion, Upgrading to a 140cc+ manual clutch engine provides the best bang for your dollar.

We do not recommend any engine with a 1 down 3 up shift pattern, These engines have an inherent problem with false neutrals, which is why you see all engine from FastTrails with 'all up shift patterns'>

It is also important to spend a little extra and get a 'start in any gear' engine. These engines have the Clutch Mounted on the main shaft of the transmission rather than the crankshaft. A much stronger, reliable design.

Those offered by companies like Fast Trails Performance, who specialize in the Sachs Madass, are very easy to install as no modifications to engine casing (for larger sach motor mount) or electrical (for sachs madass 3 phase stator) are necessary.

With a Performance 140cc engine, or Lifan 150cc engine (one of the most 'streetable' upgrades you can expect massive increases in performance.

Example: FTP 150cc Madass engine kit, FTP 39Tooth rear sprocket, FTP heavy duty 428 chain, and FTP big bore exhaust (with catalytic converter still in place), will net over 60mph.

For ALL OUT Sachs madass performance an example is FTP's ultimate Kit.

Madass 160cc Engine package, with optional 172cc Big bore kit and Performance 4 valve head, 39T rear sprocket, 428 Chain, Performance CDI box, Big bore exhaust, and Koso Flatslide carb :

An easily attainable 70mph, Wide open, with very comfortable cruising speeds of 55-60mph.

First Gear Madass Wheelies are possible with most 140-160cc engines. And I don't mean 'clutch it up wheeles', I am talking gas it and yank on the bars! The heavy Madass is fairly well balanced though, so once you get comfortable with the balance point, you will get looks of disbelief while riding out long 1st gear wheelies!!!

Things we always check on bone stock OR modified Madass bikes:

1) the nuts holding the rear fender on can back out and let the bolt under the fender come into contact with the rear tire, wearing a grove in it and possibly ruining the tire.

2) The 'adjuster' nut and bolt on the rear brake pedal can back out if not adjusted and tightened correctly. This can result in the rear brake dragging, resulting in worn brake pads, overheated discs and/ or calipers, and possible engine overheating/ damage.

Stay tuned for more tips, upgrades, and videos from

Fast Trails Performance Ebay Store  is a world leader in Performance upgrades for the Sachs Madass, With extensive testing knowledge to draw from Fast Trails Performance knows where and how to spend your Madass money for maximum gains.

Guide ID: 10000000013894459Guide created: 10/15/09 (updated 08/31/13)

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