Difference between revisions of "Motobecane"

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Under the name [[MBK Company|MBK]], the company continues to manufacture scooters for the [[European]] market.
 
Under the name [[MBK Company|MBK]], the company continues to manufacture scooters for the [[European]] market.
  
==Repair Guides==
+
Spark, and Timing  By Dan Adams  version 1.2
 +
 
 +
First read Freds guide http://www.mopedarmy.com/resources/articles/print/10/ it is a good resource, and for most mopeds it answers the questions you probably have.  Motobecanes are a little different, and Fred’s guide on checking, and setting timing does not really apply to motobecanes, that is why I put this together
 +
 
 +
Pics are at the end of this document
 +
 
 +
Before we begin
 +
Starting a Moby
 +
Hold the decompression lever and pedal (rolling or not) as soon as you see the speedo lights shine (or are certain it is turning over) let off the decompression lever and give it a bit of throttle. 
 +
 
 +
Things you should get
 +
-Carb Cleaner
 +
-Multimeter
 +
-Terminal strip
 +
-Emery boards (or fine sand paper)
 +
-A few spark plugs (Champion L86c, NGK B5hs) gap should be .4 -.5mm (keep one extra in the container under your seat always)
 +
-Small plastic ruler with millimeter measurements
 +
-Cam/clutch puller (needed to reset timing) Moby specific PIC 1a
 +
http://mopedwarehouse.com/catalog/product_info.php/cPath/27/products_id/381,
 +
Or 2 arm puller like in picture
 +
 
 +
 
 +
First you need good spark. Get a NEW spark plug (Champion L86c, NGK B5hs) attach it to the plug cap, clamp the plug cap to the engine PIC 2, and get in a dark place if possible.  Now attempt to pedal start the moped while looking at the plug, you should see a nice blue spark.  If you have spark, skip to Check the Timing, if not check the following.
 +
Note- Some mopeds need a good brake light bulb to run, Not Mobies.
 +
 
 +
1- Disconnect the wires that connect to each other near the ignition coil.  Keep the wire connected to the coil, but disconnect the other wire that is attached.  This will disable the kill switch which is often faulty.  I recommend leaving it disconnected for these reasons. -You will still be able to stop the engine using the decompression lever
 +
-You take a very bad switch out of the circuit that can short out and cause problems
 +
-You will never pedal around the block with the bike in the off position.
 +
-The horn portion of the switch will still work
 +
 
 +
2-Clean your points, to do this you will need to pull off the flywheel cover, which can be very difficult.  With any luck your flywheel nut has been completely stripped out.  The flywheel cover is Reverse thread you will need a 3/8” ratchet, and probably a pipe to fit over it to get some good leverage PIC 3.  You will need to keep the engine “locked” to be able to unscrew the flywheel cap.  The motobecane workshop manual specifies a piston stop, but I have had good luck using a second ratchet with a *mm ratchet, holding the clutch nut, and stopped against the pedal PIC 4 If you still can not get it off, trying heating up the nut with a butane torch before re attempting.
 +
Open and close the points, does the point’s connection look solid? PIC 5  Do the point surfaces look clean?  Spray some carb cleaner on an emery board and place it between the points.  Let the points close, and pull it through.  Do this a few times for each side, then pull a dry clean piece of paper through.  Points gap should be .35mm at max, resize if necessary using flat head screwdriver.  Replace flywheel cover, and try to start.
 +
 
 +
3-Remove spark plug cap from external coil and examine plug wire where it makes an electrical contact inside the coil, this connection is often bad.  Is the wire corroded? Does there look like a chance the connection was not tight?  Strip a half inch of the insulator off the spark plug wire, then cut the copper off so it extends ¼”, push the copper out to the sides, and push a small screw driver into the opening to create a small opening PIC 6.  Now carefully attach the spark plug wire to the coil, make sure the connection you just cleaned up fits snugly on the coils.
 +
 
 +
4-Examine all wires, and terminations through out the moped, and inside the headlamp. Look for places the wire seems damaged or crimped, or the connections seem loose, or corroded paying close attention to the connecting block behind the engine.
 +
I recommend replacing the connection block with a new terminal strip (radio shack) PIC 7 cut off a 4 connection piece, cut and strip the wires, and make nice new connections using the terminal strip.
 +
 
 +
Checking the timing  You do not need to have the flywheel cover off to check the timing, but it will help you understand how it works to see the movement happening.
 +
Pull the black, and brown wires off the stator plate, disconnect the grey wire that is connecting the stator plate with the spark plug, and the kill switch, connect a multimeter to the grey wire you just disconnected, and the other end to the engine ground.  Set the multimeter to continuity, and then turn the engine over by hand.  With every rotation the multimeter should change from open to closed circuit, you should see the points opening and closing as well. PIC 8
 +
(with some mobies you must disconnect all 3 wires from the points, then attach the multimeter ends to each side of the points)
 +
    With every rotation you make the piston goes up and down once.  You want the Piston to be 1.5 - 2mm Before the top dead center of the cylinder (TDC=Top dead center) exactly when the points open. (cady, commuter, mobyX 1.5mm,  40 and, 50 series 2mm)
 +
Remove the spark plug, and wedge the ruler in the engine heat sink near the spark plug hole, place, and hold an allen wrench so the long side is resting against the top of the cylinder.  Now as you turn over the engine the allen wrench will go up and down with the cylinder, and the multimeter will be displaying the point’s status. PIC 9 You want the points to open (become an open circuit) right when the allen wrench is 1.5 - 2mm before TDC.
 +
 
 +
Setting the Timing for this you will need a cam puller (see PICS 1a,1b) remove the cam, and push it back onto the rod gently into the position you think is right.  After doing this, re check the timing again to see if it is right (it will probably take a few attempts to get it right).  Once you have it right, put a small piece off wood against the cam, and bang it firmly back on with a hammer, check the timing one more time before replacing the flywheel cover.
  
 
==Performance Tuning Guides==
 
==Performance Tuning Guides==

Revision as of 15:22, 6 August 2006

Motobécane was a French manufacturer of bicycles, mopeds, motorcycles, and other small vehicles, established in 1923. "Motobécane" is a compound word made up of two colloquialisms stuck together. "Moto" is a slang word for motorcycle; "bécane" is slang for "bike."

In 1981, Motobécane filed for bankruptcy, and was subsequently purchased by Yamaha and reformed in 1984 as MBK; the French company continues to make motorscooters, and has no relation to Motobecane USA, which imports bicycles from Taiwan and China, manufactured to their specification under the Motobécane trademark.

Most moped companies were short lived enough that the evolution of their logo was slight or never happened. The Motobecane logo is an exception to this as it changed numerous times throughout the evolution of the company.

Bicycles

Motobécane was a major and respected manufacturer in the French bicycle industry. The frames on Motobécane's mid-to-upper end bikes were typically double-butted lugged steel made from Vitus or Reynolds 531 steel tubing with elegant Nervex lugs. Thus, they were light, sturdy, and well made. Motobécane finished their frames in exceptionally beautiful and high-quality paints, a practice not often followed in the French bicycle industry. Considered the second most prestigious French bicycle (after Peugeot, whose more durable design they emulated, but ahead of Gitane), Motobécane's mid-range bikes were an exceptional value; the company kept prices reasonable by matching their high-quality frames with lower-priced, but higher-quality components from Japan, at a time when their competitors were putting higher-priced, lower quality French components on their mid-range bikes. Motobécane bicycle models included the Nomade, Mirage, Super Mirage, Super Touring, Grand Touring, Sprint, Jubilee, Grand Record, Le Champion, and Team Champion.

In addition to the standard diamond frame bicycles, Motobécane also produced mixte frame versions of their bicycles; the mixte frame Grand Touring had twin lateral stays in place of a Top tube, extending from the head tube to the seat tube, while the Super Touring and Grand Jubilé had a single top tube sloping down towards the seat tube, but diverging into twin lateral stays just before joining with the seat tube. Later mixte Grand Touring models also used this design. Motobécane also produced a tandem bicycle.

Vintage French bicycles, including Motobécanes, are often sought out today by experienced riders for their value as a fixed gear or track bike conversion; for others, the unequaled pleasure of riding a vintage, well-made lugged steel bike is its own reward.

Buyers should be aware that many French bicycles manufactured before 1980 use the old-style French reverse-threaded bottom brackets, which can be difficult to find, although they are still available new through manufacturers such as Phil Wood, as well as through the used market. However, Motobecane broke ranks with other French manufacturers, beginning in the mid-seventies, by using Swiss-threaded bottom brackets, which are available through the same sources as the French-threaded bottom brackets, and buyers should be aware of the thread difference when replacing their bottom brackets.

Mopeds

Motobécane introduced a moped, the Mobylette, in 1949; over the next 48 years, Motobécane manufactured 14 million Mobylettes.

Scooters

Under the name MBK, the company continues to manufacture scooters for the European market.

Spark, and Timing By Dan Adams version 1.2

First read Freds guide http://www.mopedarmy.com/resources/articles/print/10/ it is a good resource, and for most mopeds it answers the questions you probably have. Motobecanes are a little different, and Fred’s guide on checking, and setting timing does not really apply to motobecanes, that is why I put this together

Pics are at the end of this document

Before we begin Starting a Moby Hold the decompression lever and pedal (rolling or not) as soon as you see the speedo lights shine (or are certain it is turning over) let off the decompression lever and give it a bit of throttle.

Things you should get -Carb Cleaner -Multimeter -Terminal strip -Emery boards (or fine sand paper) -A few spark plugs (Champion L86c, NGK B5hs) gap should be .4 -.5mm (keep one extra in the container under your seat always) -Small plastic ruler with millimeter measurements -Cam/clutch puller (needed to reset timing) Moby specific PIC 1a http://mopedwarehouse.com/catalog/product_info.php/cPath/27/products_id/381, Or 2 arm puller like in picture


First you need good spark. Get a NEW spark plug (Champion L86c, NGK B5hs) attach it to the plug cap, clamp the plug cap to the engine PIC 2, and get in a dark place if possible. Now attempt to pedal start the moped while looking at the plug, you should see a nice blue spark. If you have spark, skip to Check the Timing, if not check the following. Note- Some mopeds need a good brake light bulb to run, Not Mobies.

1- Disconnect the wires that connect to each other near the ignition coil. Keep the wire connected to the coil, but disconnect the other wire that is attached. This will disable the kill switch which is often faulty. I recommend leaving it disconnected for these reasons. -You will still be able to stop the engine using the decompression lever -You take a very bad switch out of the circuit that can short out and cause problems -You will never pedal around the block with the bike in the off position. -The horn portion of the switch will still work

2-Clean your points, to do this you will need to pull off the flywheel cover, which can be very difficult. With any luck your flywheel nut has been completely stripped out. The flywheel cover is Reverse thread you will need a 3/8” ratchet, and probably a pipe to fit over it to get some good leverage PIC 3. You will need to keep the engine “locked” to be able to unscrew the flywheel cap. The motobecane workshop manual specifies a piston stop, but I have had good luck using a second ratchet with a *mm ratchet, holding the clutch nut, and stopped against the pedal PIC 4 If you still can not get it off, trying heating up the nut with a butane torch before re attempting. Open and close the points, does the point’s connection look solid? PIC 5 Do the point surfaces look clean? Spray some carb cleaner on an emery board and place it between the points. Let the points close, and pull it through. Do this a few times for each side, then pull a dry clean piece of paper through. Points gap should be .35mm at max, resize if necessary using flat head screwdriver. Replace flywheel cover, and try to start.

3-Remove spark plug cap from external coil and examine plug wire where it makes an electrical contact inside the coil, this connection is often bad. Is the wire corroded? Does there look like a chance the connection was not tight? Strip a half inch of the insulator off the spark plug wire, then cut the copper off so it extends ¼”, push the copper out to the sides, and push a small screw driver into the opening to create a small opening PIC 6. Now carefully attach the spark plug wire to the coil, make sure the connection you just cleaned up fits snugly on the coils.

4-Examine all wires, and terminations through out the moped, and inside the headlamp. Look for places the wire seems damaged or crimped, or the connections seem loose, or corroded paying close attention to the connecting block behind the engine. I recommend replacing the connection block with a new terminal strip (radio shack) PIC 7 cut off a 4 connection piece, cut and strip the wires, and make nice new connections using the terminal strip.

Checking the timing You do not need to have the flywheel cover off to check the timing, but it will help you understand how it works to see the movement happening. Pull the black, and brown wires off the stator plate, disconnect the grey wire that is connecting the stator plate with the spark plug, and the kill switch, connect a multimeter to the grey wire you just disconnected, and the other end to the engine ground. Set the multimeter to continuity, and then turn the engine over by hand. With every rotation the multimeter should change from open to closed circuit, you should see the points opening and closing as well. PIC 8 (with some mobies you must disconnect all 3 wires from the points, then attach the multimeter ends to each side of the points)

    With every rotation you make the piston goes up and down once.  You want the Piston to be 1.5 - 2mm Before the top dead center of the cylinder (TDC=Top dead center) exactly when the points open. (cady, commuter, mobyX 1.5mm,  40 and, 50 series 2mm)

Remove the spark plug, and wedge the ruler in the engine heat sink near the spark plug hole, place, and hold an allen wrench so the long side is resting against the top of the cylinder. Now as you turn over the engine the allen wrench will go up and down with the cylinder, and the multimeter will be displaying the point’s status. PIC 9 You want the points to open (become an open circuit) right when the allen wrench is 1.5 - 2mm before TDC.

Setting the Timing for this you will need a cam puller (see PICS 1a,1b) remove the cam, and push it back onto the rod gently into the position you think is right. After doing this, re check the timing again to see if it is right (it will probably take a few attempts to get it right). Once you have it right, put a small piece off wood against the cam, and bang it firmly back on with a hammer, check the timing one more time before replacing the flywheel cover.

Performance Tuning Guides

Converting from stock Gurtner AR Carburetor to a Dellorto SHA carburetor

Motorcycles

Motobécane manufactured motorcycles from its inception in 1923 until its demise in 1981.

External links