Peugeot 103 streetfighter, la derniere ligne droite

Enfin j’espere…

I’m starting to see the light at the end of the tunnel and should be able to fire up my street bike project very soon. I’ve been waiting 2 years for this moment.

Today was important, I hooked up all the water hoses to the motobecane stock radiator, the temperature sensor and the electric water pump. I just need to wire the pump to a regulator/rectifier or a small separate 12V battery.

Here’s what’s left on the list before finally starting the engine and do a bunch of test runs before painting the bike:

Finish all the electrical wiring (cdi, regulator,battery, fuse, water pump, vapor tachometer + temp gauge, lights, kill switch), lock the pedal shaft so the pegs don’t spin, custom make heavy weights for the malossi variator + the doppler spring way too strong, install the chain, the disc brake lines, the throttle + cables, mount the motobecane engine mount rubber bushings (rare on a kitted peugeot frame but recommend to absorb the vibrations and prevent breaking parts like the exhaust, etc…)  Now I wish I would have bought a 50cc h20 engine for less vibrations and overheating problems but at the time I had the “small piston complex” and wanted the biggest bore available like everybody else. That being said, the bike is so heavy that I might need the torque for a more comfortable ride and forget about a screaming engine or top speed.

Few hours away…

I just have to finish all the electrical wiring, install the throttle + choke cables, the fuel line, brake lines and I’m ready to fire up this bad boy!

We learn everyday. I just found out on Facebook that the peugeot 103 RCX/SPX engine is actually rubber mounted and the mount comes in 2 brackets connected together with a thick square piece of rubber between them. It seems like you take the engine down by just removing the bolt on the lower bushing and leave the black bracket on the frame. The more popular 103 SP version in the US doesn’t come with rubber bushings, the bike vibrates a lot with a powerful kitted engine often braking the exhaust. The answer might be to modify that engine mount by welding a rubber bushing just like on the 103 spx (left photo). The big polini cases with aluminum arms vibrate and sometime a powerful engine set up brakes the arms. The best cases are the malossi ones with 70cc kits and 21 mm carb minimum or the smaller polini cases (but expansive) using the stock peugeot mount steel bracket (maybe reinforced or rubber mounted would be the best) with a 50cc kits 19 mm carb max.

Bonus pics from french blogs:

A peugeot 103 spx prototype project with malossi cases, peugeot malossi crank 42,1 mm stroke (instead of 39,1 mm stock stroke) + new 85 mm rod (instead of 75 mm) adapted from an AM6 Minarelli scooter crank, Piaggio/minarelli scooter malossi MHR 70cc h20 kit (try to find the studs…), PVL digital ignition, Stage 6 exhaust modified, Conti power jet 28 mm carb, Conti CRX 4 petal reed block, RGD peugeot 103 variator, Giraudo clutch pulley, Giraudo engine spring. Rad…!


A new electric drag scooter prototype by MXS Custom. Check out that cool white Teflon 3D mold of the Zuma scooter cylinder ports.


  1. Eric

    two questions about your Streefighter…..1st. how are you gonna lock the pedal shaft?
    2nd do you prefer the variotop over the er3? looks super rad by the way!! nice work!!

  2. tomahawktuning


    1st, couple of options to lock the pedal shaft, like drilling a hole in the hardened steel shaft and tap the frame to lock the shaft with a screw, or bolt a small bracket between the shaft’s bicycle sprocket and the frame, or weld a small bracket on the shaft (after cutting off the sprocket) and bolt it on the frame just like I did on my streetfighter.

    2nd, with a stock clutch function set up and 13 mm belts, I prefer the doppler Er3 100 mm variator but I already had a malossi variator 115 mm laying around and it looks cool. I might invest in an Er3 in the future but I’ve already spent enough money on that bike.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s