advance unit springsThis is an interesting thread. I think it would be useful to separate out the two issues.
Timing differences from Left to Right Timing differences have a number of causes, but they are not related directly to the advancer or the points cam, unless it is moving relative to the camshaft from one cylinder to the other. If that occurs, timing will be different as teh points cam oscillates back and forth. A more common problem is that the points are not well matched or the points plate is slightly out of position. On all the CB72 and CB77 I set up, it was common to have to set the points gap quite differently from one cylinder to the other. I often ran out of adjustment on the moving set. The only simple fix was to set one set of points tighter to advance that cylinder and teh other set wider to retard that cylinder relative to each other Advancer slack and timing Too much advance at the top end is potentially more damaging than too little at the low end as was pointed out earlier. But there's a solution and that is to limit the travel of the advancer. I have never seen neoprene on a cam sprocket so that may be a modification or a later change. In principle it doesn't matter if the holes are welded and machined back or the arms. The rivets are quite soft and easily drilled out or pressed out. Then you have choices. Add some weld or braze the the hole and clean it up with a mill or dremmel until you get the range of movement you want. Or you could mil out the holes and press in a custom ring of slightly smaller than stock size and sweat that into position. Set the advancer up in a cam in a spare head with pointer and degree wheel and tweak it until you get teh range you are looking for. I'd suggest 10 degrees static for slightly sharper bottom end response and 35 degrees (at the crank) for a total of 45 degrees. Stronger springs slow the rate at which the arms throw out and that slows the rate of advance. Weaker springs allow the advance to occur earlier. Slop allows the advancer to start earlier. I used to weld up the advancer on race bikes with points, and now use crank mounted ignition with fixed timing which is really not as much of a problem as you might expect. Poor low speed performance could also be a worn motor, partially blocked passages in the carb, etc. [/b]
You can look at the FAQ item #6 and see how many of this forum have timed their points/engine.
As things are in today's world not everyone owns a Timing Light but can make the Light I suggest/use and to no ones surprise they can tune/run/ride just fine. You are funny Teazer. To quote you! Also the NEOPRENE is on the Advance Weight at the bottom/contact area of the limiters attached to the weights so as ya ride along ya don't get a Clack-Clack as you ride and the weights move back to idle position. There are many ways to repair the loose rivets and ya have listed several which we on the forum know of and have used for many a year. Believe it or not we are a rather well informed group (share things with each other) and have been through this many times. I pray this will enlighten you that we are not Ignorant and have had lots of fun even up to today. ..........lm
Er,
That earlier quote about clack clack wasn't me. Did someone else have the same on line name previously, or was it just a joke? As for what people know or don't know, I have no idea and make no assumptions. In that particular thread it appeared that the guys with the problem were struggling to work out an appropriate solution, so I made a suggestion. I don't recall mentioning tightening rivets though. Are you just suggesting that my input is not wanted or am I misunderstanding you? Something odd about this correspondence. care to clue me in.
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