Genuine vs. counterfeit parts
 
There is a proliferation of cheesy fake CJ parts these days as well as the now-common practice of offering "vintage" CJs that are anything but. As a result, the CJ750 is suffering from a reputation for being of poor quality when in fact a real CJ is a very good machine. Gerald Gardebled has been compiling information to assist you in the identification of genuine parts.
 
Rubber sleeves for the air intakes. The vintage example is on the right. Another excellent example of how quality has diminished over the years.
 
A vintage steering damper friction plate from a 1961 CJ750.
The same part but found in a PLA stock from the 1970s.
This is what can be found in the shops supplying CJ parts today. You can see that the vintage and PLA plates are of far better quality than the cheesy new ones.
 
Vintage jugs are of much higher quality than new ones. Take a good look at the intake on this newly made cylinder. You can clearly see the poor workmanship.
The exhaust is equally bad.
A vintage PLA-issue jug. Look how clean the exhaust opening is.
Same for the intake. Very good work here, much better than the newly made jugs.
One of the biggest issues with the newly made jugs—the air flow passages are blocked. The result is poor cooling.
Another example.
PLA jug with virtually no obstructions in the cooling fins. It's astonishing how poor the quality of a new jug is by comparison.
Another example of clear cooling fuins.
And one more. Not shown but worth a mention, the valve guides on new jugs often have too large a diameter so you burn oil. Your bike looks like a steam train. And in some cases the diameter of the cylinder bore is actually too small for the piston!
The carburetor intake and, as you can clearly see, the passageway is not that clean.
Compare this vintage jug with the image above. Look how smooth the interior surface is. This does make a difference in performance.
 
Final drives. The one on the left is the newer model. The one on the right is a PLA drive from 1971.
Look at the difference in the casting quality of the casing in these detail images.
It's pretty clear that the PLA-made casing is much better made than the newer one.
 
This is a general view of a genuine CJ tank. It's constructed of heavier steel and has very nicely done welding.
This offset filler toolbox combination fuel tank is not genuine. Such a tank was never offered on authentic Changs and is of poor quality.
The kneepad bracket on this counterfeit tank is the wrong shape and in the wrong position. It cannot be adjusted. It's made from very thin sheetmetal and won't last very long.
The genuine kneepad bracket has holes for adjusting its position.
It's also made from much heavier steel.
The lid on the counterfeit tool box tank is too thin. It will bend and break easily.
This detail of a genuine toolbox lid illustrates the heavier gauge of steel used.
Here's the whole thing.
A counterfeit toolbox lid hinge is welded on the outside instead of the inside. This type of hinge will break fairly soon.
The toolbox lid hinge on a genuine tank.
Counerfeit tanks sometimes have this type of catch for the toolbox cover instead of a proper bracket.
The latch bracket on a genuine tank.
Counterfeit tanks are constructed with thin metal with poor welding. The welds are susceptible to cracking and the tanks are notorious for developing leaks. They are sold on the internet for $200 or more but cost only $20! LRM offers these for $20 to anyone who wants a fake tank. The genuine CJ tanks are hard to find now but Mike Weaver can supply you with a high-quality Russian-made toolbox tank for your Chang.
 
This shot shows a counterfeit CJ frame where the driver's seat can hit the middle tube when it has weight on it. Essentially it means the bike has no seat suspension—not so funny when you ride on bad roads.
For comparison, the same tube from an genuine frame. The tube is shorter the seat won't bottom out.
This image shows the plate where the gas tank sits on a counterfeit CJ frame. The metal is too thin on some of them. You can actually bend it with your hands.
Not so on this genuine frame.
Here's an example of a gas tank bracket being located slightly off on a counterfeit CJ frame.
To compensate they elongated the holes so the tank will mate up to them.
The bracket can lose quite a bit of its integrity as a result.
This image shows the "workmanship" on a counterfeit CJ frame.
On this counterfeit frame the bracket welded below the tube limits the rotation of the steering head.
Also, the steering damper plate is too long. In this example, the steering damper is totally useless because there is no contact with the plate.
 
This shot shows a phony CJ frame where the driver's seat can hit the middle tube when it has weight on it. Essentially it means the bike has no seat suspension—not so funny when you ride on bad roads.
For comparison, the same tube from an original frame. The tube is shorter the seat won't bottom out.
This image shows the plate where the gas tank sits. The metal is too thin on some of them. You can actually bend it with your hands.
Not so on this original frame.
Here's an example of a gas tank bracket being located slightly off.
To compensate they elongated the holes so the tank will mate up to them.
The bracket can lose quite a bit of its integrity as a result.
This image shows the "workmanship" on a counterfeit CJ frame.
On this frame the bracket welded below the tube limits the rotation of the steering head.
Also, the steering damper plate is too long. In this example, the steering damper is totally useless because there is no contact with the plate.