Wednesday, January 29, 2014

My "This Ole" Motobecane M11 Post. PIC HEAVY!

Time for a big long winter update! All blog and no play makes Mike a dull boy X 1000000.

A couple months ago I got my hands on a Motobecane M11. These have an interesting history and design. I dug for a few days and learned a lot about the M11 and M12 Weeky models. This is going to be more of a info and findings ramble, so sorry if this gets messy. I'm going to start out with what I have come to understand about the production dates and design of the M11.

The M11 was designed in the early 70's by Anker Laura. It was assumed that it would have been put into production by ~1973 but Laura fell in to financial trouble. Laura was bought out by Velosolex who soon developed financial troubles of their own.  In 1974 with hopes of a revamp a Laura engine known as the M56 (used on many U.S. Batavus mopeds) was used on the previously Morini MO1 powered European issued Tenor GL and GS models. 

Solex didn't have the finances to produce the already designed M11 so they used only the engine design on the Tenor. The engine designed was known as the Laura M54 and came on all of the Canadian and American Solex Tenor GL models. This differed from the M56 design by having the pedal sprocket on the right that ran to the rear wheel, the rear wheel had a freewheel, and the clutch plate, belt, and pulley were on the left of the engine. Searching for the M56 and M48 is funny because BMW also made the same numbered models. The Solex Tenor was in production until 1977. 

In 1974, Velosolex was bought by Renault and then sold to Motobecane in exchange for shares.  Throughout the late 70's Motobecane slowly struggled with sales. The base line moped went from the Cady, to the Ranger,  to the final M11 in 1978.  As it was not designed originally by Motobecane, it was not aesthetically pleasing to Moby lovers (or any one else for that matter).  The M11 was a flop and many people look at it as one of the last straws that led to Motobecane's bankruptcy in 1981.

After the bankruptcy in 1981, Motobecane was acquired by Yamaha and was rebranded as MBK in 1984. As far as the M11 with Laura engine went, the production ceased in 1983. The MBK M12 Weeky ('84 - '85) and MBK Weeky Cacharel ('86) utilized the tubular chassis of the M11. Since the M11's M54 engine had a a bad reputation, the Weeky line went with the already established German made 505 1-D engine.  Ultimately the stigma of the M11 design led to the Weeky line failing as well.  Well I think that about covers the conception and failure of the design.

Technical Information about the M11-LC:
Bore: 39mm
Stroke: 41.8mm
Displacement: 49.9cc
Timing: 1.5mm BTDC
Points gap: 0.3 - 0.4mm 
Spark plug: champion l 88 a
Flywheel rotation: Clockwise

Next is catalogs and translations of the M11 and M12 Weeky models.

 M11 LC 
semi-horizontal engine. 
new automatic centrifugal clutch. 
tubular structure. 
suspensions front and rear telescopic. 
brakes front and rear drum brakes 70mm. 
flashing flexible montes. 
preinstalled theft pin - key. 
color: pearl gray.

M11 N
semi-horizontal engine. 
new automatic centrifugal clutch. 
tubular structure. 
suspensions front and rear telescopic. 
brakes front and rear drum brakes 70mm. 
preinstalled theft pin - key. 
color: red and blue Baccarat France.

M11 ND Contact
semi-horizontal engine. 
start with electric starter.
new automatic centrifugal clutch. 
tubular structure. 
suspensions front and rear telescopic. 
brakes front and rear drum brakes 70mm. 
flashing flexible montes. 
preinstalled theft pin - key.

color: red and blue Baccarat France.

Semi-horizontal engine. 
Switching electric starter. 
New automatic centrifugal clutch. 
Tubular structure. 

AV suspension and telescopic AR. 
Piece alloy wheels. 
Front and rear brakes drum 90 mm. 

Mounted flashing flexible. 
Theft pin hardened steel - key. 
Color: pearl gray.

 Sweet Green!

Weeky M12
This line and the weight of the super form . This is why it to success.
Thanks to a tubular structure, Weeky does not exceed 45 kg and goes on stand without effort . The horizontal position of the cylinder lowers its center of gravity and allows on - the ride without any hang.
light and handy, the Weeky really starts to shift your, requires no maintenance Particular, stays clean thanks to its entirely transmission housing swallows bumps and sidewalks ( fork telescopic double acting shock absorbers front and rear mounted swing arm ) and has a system of freinade incisive.
On motor plan, the powertrain has the engine " Booster. " A brand new MBK design, which ensures the dice power at low speeds and accelerations . Breath in and score nerve at a red light ...

An automatic clutch in oil bath , and a primary transmission gear , further improve the performance of the group. which results in a significant fuel economy (2.11 / 100 top speed ) . Unlicensed dice 14.


Booster principle allows low speed to extend the flow of gas exhausts that pass because of their low speed by the additive tube, thereby increasing power. 

At high speed, the gas velocity is such that they no longer pass through the Booster, thus achieving a better understanding of resonance between the exhaust system and the engine at all speeds.

M12 Weeky in "de bruit et de fureur" 

 MBK Weeky Cacharel with 505 1-D
MBK Weeky Cacharel with 505 1-D

The following is a TON of photos of any and everything I thought was interesting about my M11.
This is my M11, what a good looking bike.

It's hard to see while the engine is on the bike but the ignition side case looks very similar to an AV7 case (see pics below). Also I want to point out these came with a Novi ignition. 

Everything packed in there, reminds me of a Derbi Variant.
I need to make a new intake for a Dellorto, it will be tricky because it has to clear the pivot mount but sit low enough to be under the plastic cover. Here is a picture of the stock intake (below).

Sweet rack!

Clutch side. Notice the clutch arm and decomp, they are both pulled with the same lever when starting the engine. 
Here is a picture of the cable and splitter, Not to self: DONT LOSE THIS!
Cylinder and head are unlike the style used on the Solex Tenor (pictured below).

The holes in the frame tube were for the security pin to sit in while you were riding.
I didnt want to harm this pipe so I found a donor stock Peugeot pipe to cut up. I found an old honda pipe and welded it to the threaded header. I havent photographed it yet but its on the M11 and looks good. I havent really noticed any performance gains out of the pipe. Im hoping with a bigger carb I will see an improvement. 

This drunk ass team rando girl stopped in to the garage and started touching everything... annoying.
Good look at the large left engine case. Below is the subframe differences between the M11 with Laura M54 (left) and the M12 with 505 1-D (right).

I use self tapping screws a lot on mopeds nowadays. 

Ok so the strange thing about this clutch is that it's different than the clutch shown in the manual (below). The one in the manual appears to be a very similar clutch in the Laura M48 engine. 

As you can see this dry clutch has ridges on the pads and bell, it isnt smooth like some other clutches. This style of clutch reminds me of the Benelli G2 wet clutch (below).

It also reminds me of the MK Puch racing wet clutch (below).

Even though the clutch pads seem different on the M11 dry clutch the clutch plates seem to be VERY similar on the 3 compared clutches. Treatland used to sell the MK clutch puller (below) that would more than likely work to pull the M11 and G2 clutch plate as well. Luckily you can service the clutch on the M11 and G2 without removing the clutch plate. 

For comparison next to a Tomos A35 clutch. I ended up putting a modified Tomos clutch spring on my M11 when I put it all back together.
Better look at the grooved clutch pads.

The piston and head gasket look identical to AV7.

Looks very similar to a 2hp Puch cylinder.
I really wish this was flange mount and not threaded, but it is Moby!

Dug out an av7 cylinder and it slid on fairly easily.
This is a TDC and the port timing seemed to be right on with the AV7 cylinder on the M54 bottom end. Something I thought was strange was that the Laura M48 and M56 engines both have a 38 mm stroke and the AV7 has a 41.6mm stroke. Im assuming the Laura M54 had the same stroke as the M48 and M56 so Motobecane must have adapted the M54 with a longer stroke when it was released on the M11.
The AV7 head fits fine. I may try to eventually fire it up with an AV7 top end just to experiment, there are a few things that would make it difficult. The first and most obvious is the fact that the cooling fins on the AV7 are for more of a vertical application and not horizontal, it would probably not get proper cooling. Secondly, if you look above at the M11 cylinder, the intake port is on the middle of the the cylinder (from side to side). On the AV7 cylinder the intake is more on the left and the existing intake/carb setup wouldnt work because it moved the assembly to the left and it would hit the frame.

Im very excited to see how fast I can make the M11. I think with a new intake, bigger carb, pipe, and mild porting I could be doing a good 35-40 mph. Currently it only goes 25mph and that is not cutting it in Chicago traffic!

The tubular frame is nice looking and is rather light, lots of options. I think the frame would be a good Derbi flatreed candidate due to the frame split under the tank. Check out these pics of a modified M12, that paint job looks FAST! + 1 for mountain bike forks.

Big Thanks to Rebel Moby with helping me figure out with some of the fine details.