Difference between revisions of "Derbi"

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basic info
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{{TOCright}}
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==Engine Intake Info==
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*'some late 85's, 86's and '87 SLE should be a flat reed engine (the flat reed engine came into play in late '85)
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**If the engine and swing arm move with the suspension, it is a flat reed
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**If the motor is rigidly attached to the frame it's piston port or pyramid reed
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*the 81 SLE was pyramid reed
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*Derbi RD's were pyramid reed
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*Derbi Diablos and Lagunas piston port
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*the Derbi DS50 scooter is flat reed
  
"86 and 87 sle should be a flat reed engine, the flat reed engine came into play in 86, you can tell if it has a steel rear swingarm on a variant step thru, it is a flat reed, if its alloy, its piston port or pyramid
 
  
the 81 sle was pyramid reed, derbi rd’s were pyramid reed, derbi diablos are piston port, derbi lagunas are also piston port, the derbi ds50 scooter is flat reed'
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Derbi mopeds came with three engine sets.
  
quote by well known derbi conoseiour
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1 - Piston port , same stroke as Puch. With modifications you can put a puch cylinder on a derbi piston port bike. Super easy swap back and forth. If you are somewhat clever.
  
technical specs
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2 Pyramid Reed Derbi. Same stroke as piston port but with case inducted reeds. Not easy to swap things around, because you have case induction. So technically you could run puch kit if you sealed up either the case induction or the cylinder's intake.
  
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3 Flat reed. Basically the last edition of derbi. Much like a bunch of scooters. Very similar stroke to hobbits and minarelli horizontal scooter kits. Lot's of blasty options but not puch kits. These have DIS-similar bore and stoke to the previous two DERBI motors.
  
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==Technical Specs==
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===[[Derbi - Piston Port Engine]]===
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*cylinder inducted
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*stroke: 43mm
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*bore: 38mm
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*displacement: 48.7cc
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*compression 8.5:1
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*direction of rotation: counter clockwise facing magneto
  
Piston port engines
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Download the repair manual for Derbi piston port motors [http://www.scribd.com/doc/12933173/Derbi-Piston-Port-Engine-Repair-Manual here].
cylinder inducted
 
stroke: 43mm
 
bore: 38mm
 
displacement: 48.7cc
 
compression 8.5:1
 
direction of rotation: counter clockwise facing magneto
 
  
Pyramid reed engines
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===Pyramid reed engines===
Pyramid 3-reed valve, Crankcase mounted
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Pyramid reed engines share the same internals as piston port motors except they are case inducted.
stroke: 43mm
 
bore: 38mm
 
displacement: 48.6cc
 
compression 8.5:1
 
direction of rotation: counter clockwise facing magneto.
 
  
Flat reed engines
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*Pyramid 3-reed valve, Crankcase mounted
Crankcase 2-reed valve induction with triple transfer port distribution
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*stroke: 43mm
stroke: 40mm
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*bore: 38mm
bore: 39.87mm
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*displacement: 48.6cc
displacement: 49cc
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*compression 8.5:1
compression: 10:1
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*direction of rotation: counter clockwise facing magneto.
direction of rotation: clockwise facing magneto.
 
Max engine RPM: 6500
 
  
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===Flat reed engines===
 +
flat reed engines were completely redesigned from the earlier piston port/pyramid reed engines. They are not directly swappable to older bikes. Flat reed engines come stock with a 6 roller variator which accepts standard 16x13 variator weights. Flat reed motors also use cast aluminum rear pulleys instead of the stamped steel version on older engines.
  
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*Crankcase 2-reed valve induction with triple transfer port distribution
 +
*stroke: 40mm
 +
*bore: 39.87mm
 +
*displacement: 49cc
 +
*compression: 10:1
 +
*direction of rotation: clockwise facing magneto.
 +
*Max engine RPM: 6500 (stock configuration)
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*Flywheel and Clutch bell nuts are '''reverse/left-hand thread''' (variator side M10 x 1mm)
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*Rear pulley nut (Input shaft) is "reverse thread"
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*Front sprocket nut is M30-1.0 thread, RH
  
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See a PDF file of the flat reed engine repair manual [http://mopedcentral.com/images/DerbiEngineRepair.pdf here].
  
makin a water cooled derbi
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==Derbi Laguna Sport==
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Derbi began importing mopeds to the United States in 1978, After 2 years of this they began to market a bike specific to the US market. The Derbi Laguna Sport most likely recieved its name from the Derbi moped headquarters in the United States at the time located in Laguna Hills, CA. The Laguna Sport was designed after its Spanish counterpart the Sport Coppa (a 5-speed moped Derbi created in response to the Puch Monza).
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The Laguna Sport was sold thru 1980 and early 1981 and discontinued afterwards, There is no exact tally of how many went into production, as they were not individualy numbered. Derbi had 2 other similar models; The C-5 Diablo and RD-50 which were more oriented for motocross aplications.
  
A lot of people have asked me about this issue, and here I will try to clear any doubts about turning a moped liquid cooled. In this situation I will use a derbi variant with an old version of the (pro race for an aerox. Horizontal)
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*Lost Laguna/C-5 gas caps can be replaced with a 1 hole #8 (41mm x 33mm x 25mm) stopper from any lab store. Just be sure to run tubing from the cap down the frame to keep water and vacuum sealage out!
  
The first thing you are going to want to do is adapt the cylinder shaft/screws,
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[[Image:Laguna.jpg|frame|center|Derbi Laguna]]
For witch there is two ways of doing so.
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{{clr}}
- First is the safest but hardest way to do so. Remove the shaft/screws and fill in the holes with aluminum bar/ screw or basically fill in the holes with aluminum. And shave it flush grind etc.. You get the idea.  Now it’s as if it didn’t have shaft/screw holes.  
 
 
  
Then you place the cylinder centered and mark the new holes. So that afterwards you can preferably using a stationary drill because you could run into problems if they are not straight. drill new ones.  In this picture you can see the two screw/shafts from the right moved and the left ones unmoved.
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==Resources==
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*[[Derbi manuals]]
-the second way is the easiest way but not as reliable. It consists of grinding the screw/shafts from the inside and the holes of the cylinder from the inside as well, keep trying until the cylinder gets all the way down. It won’t go in smoothly since it will be a little bit forced to fit. But I have done it like this and I have never had any problems. With a dremel these things are really easy to do.
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*[http://www.mopedarmy.com/forums/discuss/read.php?f=7&i=52675&t=49558 Make a water-cooled Derbi]
 
(this is the chunk  piece/part that has to be ground in the inside area of the shaft/screws)
 
  
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[[Category: Moped Brands]]
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[[Category: Derbi]]
(Here you can see where the cylinder has to be ground. It does not have to reach the top of the cylinder, because the gaskets will not sit right and coolant will leak)
 
 
 
 
 
 
 
 
If you are going to make your moped liquid cooled it’s almost necessary to match the ports so that you can make good use of the cylinder. To do this once you have adapted the screw/shafts you will have to mark up to where the cylinder transfers are.
 
The way I did it was using a gasket. I used a metal gasket at the base of the cylinder then you cut it to the shape of the transfers ( kind of making a template). Here on the left of the picture you can se the gasket template already cut to the transfers on the left and center.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Then you place the gasket on the bottom end And mark/ traces what needs to be ground away. In this picture you can see the template and the marker tracings of what needs
 
grinding on the left and on the right already done .
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
and now to grind away. 
 
 
 
 
 
we run into a problem. The holes that appear when grinding there are two ways of fixing these.
 
-one of them is to weld/ fill them in with aluminum
 
-throw some kind of jb weld or other material from the outside and then grind away from the inside to make it smooth.
 
 
 
 
 
 
 
Now that we have the transfers matched the only thing left is to adjust the height of the piston. Since the derbi variant works with minarelli. For others I would have to study it.
 
(I believe he is talking about the crank arm/ piston arm whatever it is called. Is compatible from derbi variant with some minarelli ones. )
 
to do this you mount everything but the head. And you look up to where the piston reaches if it comes out to much from the cilynder just add thick base gaskets until it fits well.
 
If the piston does not reach to the top of the cylinder (which is what will happen) you will have to use a longer *piston arm , always use an arm that is bigger then what you think you will need because if you end up short you will have to buy another one. And change everything.
 
In my case with this build the length of my piston arm was 78mm I only needed 4mm to reach to the top but I put one of 85mm. you need to find one with exactly all of the same measurements  the one that I used and worked fine was this one.
 
 
Afterwards you can adjust the height by adding more base gaskets .
 
The best bearings to use with this setup are these
 
 
 
There the bottom ones
 
 
 
 
 
Once this is done you have the cylinder mounted
 
 
All you are missing is the radiator system.
 
 
 
 
 
 
 
 
These are self explanatory.  Top one talks about thermosifon hot water goes up cold water comes down no pump needed. Bottom one with a pump.
 

Latest revision as of 18:32, 15 April 2020

Engine Intake Info

  • 'some late 85's, 86's and '87 SLE should be a flat reed engine (the flat reed engine came into play in late '85)
    • If the engine and swing arm move with the suspension, it is a flat reed
    • If the motor is rigidly attached to the frame it's piston port or pyramid reed
  • the 81 SLE was pyramid reed
  • Derbi RD's were pyramid reed
  • Derbi Diablos and Lagunas piston port
  • the Derbi DS50 scooter is flat reed


Derbi mopeds came with three engine sets.

1 - Piston port , same stroke as Puch. With modifications you can put a puch cylinder on a derbi piston port bike. Super easy swap back and forth. If you are somewhat clever.

2 Pyramid Reed Derbi. Same stroke as piston port but with case inducted reeds. Not easy to swap things around, because you have case induction. So technically you could run puch kit if you sealed up either the case induction or the cylinder's intake.

3 Flat reed. Basically the last edition of derbi. Much like a bunch of scooters. Very similar stroke to hobbits and minarelli horizontal scooter kits. Lot's of blasty options but not puch kits. These have DIS-similar bore and stoke to the previous two DERBI motors.

Technical Specs

Derbi - Piston Port Engine

  • cylinder inducted
  • stroke: 43mm
  • bore: 38mm
  • displacement: 48.7cc
  • compression 8.5:1
  • direction of rotation: counter clockwise facing magneto

Download the repair manual for Derbi piston port motors here.

Pyramid reed engines

Pyramid reed engines share the same internals as piston port motors except they are case inducted.

  • Pyramid 3-reed valve, Crankcase mounted
  • stroke: 43mm
  • bore: 38mm
  • displacement: 48.6cc
  • compression 8.5:1
  • direction of rotation: counter clockwise facing magneto.

Flat reed engines

flat reed engines were completely redesigned from the earlier piston port/pyramid reed engines. They are not directly swappable to older bikes. Flat reed engines come stock with a 6 roller variator which accepts standard 16x13 variator weights. Flat reed motors also use cast aluminum rear pulleys instead of the stamped steel version on older engines.

  • Crankcase 2-reed valve induction with triple transfer port distribution
  • stroke: 40mm
  • bore: 39.87mm
  • displacement: 49cc
  • compression: 10:1
  • direction of rotation: clockwise facing magneto.
  • Max engine RPM: 6500 (stock configuration)
  • Flywheel and Clutch bell nuts are reverse/left-hand thread (variator side M10 x 1mm)
  • Rear pulley nut (Input shaft) is "reverse thread"
  • Front sprocket nut is M30-1.0 thread, RH

See a PDF file of the flat reed engine repair manual here.

Derbi Laguna Sport

Derbi began importing mopeds to the United States in 1978, After 2 years of this they began to market a bike specific to the US market. The Derbi Laguna Sport most likely recieved its name from the Derbi moped headquarters in the United States at the time located in Laguna Hills, CA. The Laguna Sport was designed after its Spanish counterpart the Sport Coppa (a 5-speed moped Derbi created in response to the Puch Monza). The Laguna Sport was sold thru 1980 and early 1981 and discontinued afterwards, There is no exact tally of how many went into production, as they were not individualy numbered. Derbi had 2 other similar models; The C-5 Diablo and RD-50 which were more oriented for motocross aplications.

  • Lost Laguna/C-5 gas caps can be replaced with a 1 hole #8 (41mm x 33mm x 25mm) stopper from any lab store. Just be sure to run tubing from the cap down the frame to keep water and vacuum sealage out!
Derbi Laguna

Resources