Tagged: peugeot 103 rcx

Melvin’s motobecane 50cc polini for sale


Melvin is selling his fast motobecane av10 50cc polini fully loaded. He’s building his next fast moped a Peugeot 103 RCX 50cc Doppler h20 electric water pump with stock clutch pulley and kick start.


Stock mbk cases, doppler crank, ported 50cc W polini kit, doppler high comp head, dell’orto 19 carb, doppler exhaust with custom ball joint, mbk cdi, kick start, doppler er3 variator, doppler clutch pulley with Tomahawk Xtreme kit + special 2 way bearing with outer grease nipple for easy maintenance, custom launch lever.


Custom frame brace, custom disc brake, custom swing arm, 5 star mag wheels, Ebr hydraulic fork with custom brace, custom clip-on handlebars,  custom seat and upholstery, LED tail light, brake light, Ruckus front headlight, 6v battery, key switch, kill switch, horn, gps aluminum mount, rotating license plate holder.

Peugeot 103 RCX project:

Frame with stock kick start imported from France. Stock clutch pulley and Doppler 50cc h20 kit from Treats. The engine will be ported, assembled and tuned by Tomahawk.



The Tomahawk moped nest is taking shape:

The roof frame is done.

Look… a little wounded bird landed next to the Tomahawk nest:

Commissioned project moby 40T frame with 6 star mag wheels + stock av10 cases, polini reed block, powerful malossi 50cc h20 Gr2 kit, stock cdi, 19 carb, stock cdi, doppler er3 variator, doppler clutch pulley, doppler spring. We’re gonna bring this awesome bike back to life with a new ebr fork + disc brake.

Two very powerful 50cc motobecane engine builds in progress:

Stock mbk small cases + stock 2 petal reed valve + 21mm carb + stock cdi, doppler er3 variator, electric  water pump.

Just got those 2 polini 50cc h20 kits from Treats. For proper seal, the heads and cylinders will be machined to fit 1x 45mm and 4x 7mm viton O rings to replace the weak polini head gasket. The combustion chambers might be machined and modified later to fit Bidalot flat head pistons. The cylinder decks will be milled down to raise the port duration to Gr2 specs and the W shape exhaust ported for high rpm monster power. That motobecane setup should be faster than my race moped peugeot 103 rcx 50cc h20 + malossi cases + 21mm carb.


Thanks Treats! treatland.tv

RCX monster green

Damn that thing is bad dude!

Peugeot 103 rcx 50cc race moped/show bike with a new paint getting ready to compete in the West Coast motorized bicycle/moped 1st race event April 7th in Southern California.

Frame semi gloss black with very light metal flakes by Master Mario.

Powder coating: wheels and seat clear reflective, swing arm and frame brace frosty black, official monster green parts + black exhaust high temp ceramic coating:

SoCal Moped Race Sat April 7th 2012 Grange Track, Victorville

The monster is track ready. It looks mean and hungry for some 18 hp 200cc 4T go kart and 12 hp 50cc h20 Morini engines. The fairings have to come back in style, plus they’re so much more efficient on the track.

First videos:

The main jet is rich to protect the engine. It four-strokes and only revs at 13,000 rpm for now. At this level of tuning those small 50cc engines pushed to their limit are very sensitive to any wrong setting or weather changes . I’ll jet it on the track and will use a velocity stack or an air box for better air flow. But in general I tend to keep the carburetion rich to protect my race engines even if they lose a little bit of power. The races are just for fun in California, we’re not running a championship and it’s not worth blowing up an engine.

High tech catch bowl from 99c store :). It prevents the fuel overflow from leaking on the race track and create dangerous slippery spots.

The gas tank leak repair with POR15 looks great.

– My motobecane Av10 50cc air cooled 19mm carb single variated with launch lever is track ready. The only thing left is to install the much needed Kawasaki NHK adjustable steering damper I got for cheap on ebay. Unlike on a big motorcycle, it has to be mounted as close to the frame as possible so that  it doesn’t feel too stiff, guru’s word. No more test runs before the race to save the brand new piston ring for maximum power on track day.

Doppler clutch trick by Tomahawk race team:

I’m using the Tomahawk pulley Xtreme kit + push start bearing upgrade HFL 3030.

The stock Doppler clutch pulley often shutters during the shoes break in period creating vibrations resulting in broken stock 6mm posts or broken stock one way bearing. A good trick is to deglaze the cluth bell and the clutch shoes after the first couple of miles just on the edges where they make uneven contact.  We did it quickly for the video but you can spend more time for a better finish. The clutch will engage smoother and later at higher rpms for super fast takeoffs. You may have to repeat the process a second time if the pulley start shuttering again. The shoes might wear out a little bit faster but when you ride a race bike or fast street bike you have to change engine parts very often, what matters for speed addicts is performance over long term durability.

My 50cc single vairated bike takes off as fast or faster than most dual variated mopeds like derbi or hobbit and pulls harder because dual variated transmissions absorb some of the power and need a lot of rpms when most of those kitted bikes use low rpm 70cc air cooled kits, or if they pop wheelies they don’t have the pull and top speed like a single variator with launch lever. I remember being faster off the line than 75cc derbis (maybe geared for top speed) on the race track with my peugeot RCX giraudo clutch pulley, 50cc air cooled stock cases single flat reed at the time and not tuned.

But a high rpm dual variated engine with a launch lever system is very effective on the track. It has been tested a long time ago in the late 80’s in 50cc french moped racing. It was at the time when the organizations were still deciding on banning or not the launch lever from “fully automatic rules”. The single variator + launch lever became legal and dominated the track for 20 years (still today in 2012, 18hp h20 50cc single variator launch lever prototype mopeds are faster than 80cc scooters on the track), but the dual variator + a launch lever was considered too powerful and banned from the rules by some organizations. It was one transmission system or the other, not both. We can’t see the engine but here’s a pic of  a 1987 50cc dual variated launch lever prototype with fairings by master tuner Pascal Fraget and same year 50cc single variated parallelogram prototype by “Willy Hubert” one of the two last companies in France who still makes the vintage fairings we can now buy in the US thanks to Treats, fairing-full-race-conti.htm



Man… the motorized bicycles with 200cc 4 stroke dual variated go kart Chinese engines ($100) are gonna have to pedal hard to match the moby av10 or peugeot 103 rcx take offs on the start lane… lol. It’s gonna be interesting to see how the light and torquy electric bikes will compare. Even though I don’t like the expensive price or trust the reliability, I might try for one race the internal rotor MVT variable advance cdi strong spark for way better low end power and higher rpm. Available at http://www.treatland.tv  motobecane-mvt-cdi-mbk-premium.htm

Thx Melvin for the demo… and the music.

– NEW 90cc cylinder kit by MXS (French/German company):

33 hp on the dyno, for AM6, Derbi euro2/euro3 and Yamaha Zuma engine cases hitting the European market soon! With the scootracing89 cases you can rip this kit on your monster moped with a Bidalot variator + special scootracing89 shaft adapter like the variated race bike below.

– French moped racing updates:

“Continental Vario” the northern organization for the french championship 50cc single variated moped is working on new official logos for 2012.  Back in the old days small 50cc engine race bikes nicknames were “cup of coffee” (Italian size) or “pissing fire”. They gave those themes to their designer to draw the first sketches. The season starts this weekend with the first race Sunday March 25th. Here are some of the 50cc single variated mopeds with fairings competing in the north. They will also add young scooter and 6 speeds racers to the mix and maybe drag racing to bring new blood and keep the event alive in the long term.

– Also:

Check out that new moped racing organization starting on the East Coast which Tomahawk is excited to be one of the sponsors. Good luck guys!

Here’s the facebook page: 185520991554569

Jesse’s race bikes: Honda Hobbit 50cc + Puch free spirit 70cc


Puch race moped project for the OPEN class 49cc to 80cc:

North East Moped Racing Presents: Cherry Valley Cup