Author Archives: Carsten Lorenzen

Puch M4 2 Speed Engine Assembly

I made another video, this time i’m assembling a Puch M4 engine. I cover the replacement of the bearings, seals and gaskets. I also show you how to measure and adjust the radial play of the shafts and the order how everything gets assembled.

The information in this video can be used for several Puch shifter engines to some extend, i will also make a video in the future of the most popular 3-4 speed engine.

Watch the video on Youtube:

Piaggio Moped Engine Tuning

I’ve made a video where i show the steps to make a Vespa moped go faster. It’s a Vespa Si engine from my friend Kim, it came with a Athena 43 mm cylinder kit, but the engine case was not adjusted for this cylinder.

I’ll show you how to enlarge the intake for a 13 mm Dellorto SHA, adjust the transfer and boost ports and adjust the inlet timing on the crankshaft. Watch the video on Youtube here:

Helpful software can be found here: Jaap’s Puch Calculator (let me know when the link is dead).

Attached is a degreewheel you can print and use, it’s made in 300DPI so the size is correct when you print it. It’s 100 mm outside, cut the inside at 77 mm from center and it fits your Piaggio engine. Click on the image for the full size.

Vespa Malossi Clutch

Just a quick warning, don’t buy the Malossi clutch for the Piaggio/Vespa engine. All the materials are very soft, there was nearly nothing left after only a few rides. Look at these pictures:

 

I used softer blue polini springs, which reduce the wear even more than the stiff black springs that it’s shipped with. Luckily i was close to home and not on a long touring ride.

The last pictures are of my new Newfren clutch that i lightened, works great so far.

Moped USB charging

When i’m riding long trips with my phone for navigation, i drain the battery pretty fast. On my Kreidler i have a 12V 80W system, more than enough power to charge my phone. But most of my other mopeds can only provide 6V and 17-18W. I’ve found a solution to charge a USB device that is ready to buy and mount. It’s a german made bicycle dynamo adapter, the model number is M172N and it’s made by a company called Kemo.

It’s rated at 0,8A charging current and it’s able to take an input voltage of 6-70VAC.

I have it mounted on my Vespa Bravo at the moment and it works great. You obviously need to turn the lights of to charge. The stock ignition only makes 18W and i have a 15W and 4W bulb connected.

Yamaha RD50M – Engine

I pulled the RD engine this weekend and disassembled everything. Of course it will get new bearings and seals, the crankshaft is still very good, as are the gearbox and clutch. But the clutch has to go, it’s a two plate model, i will try and fit a four plate clutch from a DT80.

There will be some machine work done to the crankcase, as i will fit a cylinder from a Minarelli scooter engine. The gasket surface needs to be lowered 2-3 mm, the bore for the cylinder skirts will be enlarged and the transfer ports need to be matched.

Yamaha RD50M 1979

A new project again. I’ve had this Yamaha RD50M for a while, and no plan for it. It’s a german 5 speed model, it can never be ridden as a Moped in Denmark. What better to do than a tuning project?

Right now i’m stripping it for parts that i don’t need, less weight and fewer parts that can fall off đŸ˜‰

The engine will get new bearings, seals and some porting for a larger cylinder kit. At the moment it has a 45 mm Polini kit with a 20 mm Mikuni. A good daily driver with a topspeed of 80 km/h, nothing you can win a race with. I need something faster, more about that later.

The gallery will be updated with more pictures in the future.