Not all the bikes i have seen have this plastic "guard" on the front sprocket.
Was it stock on the '79? This bike has already been converted to a 530 chain.
Is it necessary?
The guard looks identical to the one on my 81. Don't know what's happening with the extra bolts in the sprocket. Judging by the amount of goo I have to clean off the guard when I change chains, it probably isn't a bad idea; otherwise, the goo would be all over your engine.
Ah, I get it: you're talking about the plastic disk held on with the two bolts, not the guard that surrounds the sprocket. The one on my 81 was a steel disk over hard rubber or plastic. It was held in place by the centre bolt. When I went to an aftermarket sprocket, I used the steel disk, but left off the plastic bit, which wouldn't fit.
Don't know where you get sprockets, but I've had about every aftermarket one available and every one allowed fitment of the complete damper system from the '80-'82 models. So what am I missing?
As I recall, the damper requires that the sprocket have a collar so the outer surface of the plastic ring fits flush with the metal disk that holds it in place. The factory sprocket had the collar, the aftermarket's collar was too small to hold the plastic ring properly, or the collar wasn't there (I don't remember which). It looks like the picture above shows a similar situation, which is why the owner probably fabricated his own solution that uses the two threaded holes in the sprocket.
daves79x wrote:No, the metal disc holds the other two pieces in place - doesn't matter the configuration of the sprocket. The inner ring is meant to float.
Dave
Not with the configuration of my factory sprocket. The plastic ring rotates around a fairly close-fitting collar on the sprocket, it doesn't really float. The aftermarket sprocket was different enough that I judged the plastic ring wouldn't work properly, so I left it off.