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Posted by PeterD on November 11, 2006, 8:59 am
wrote:
>
>Let me post some follow-up info on my last post. I don't have any
>urgent questions, but I marked some background questions with ====>>
>
>wrote:
>
>>4 questions about an old motorcycle ignition system. Electrical
>>questions are 2 and 3, and maybe 1.
>>
>>Well, I got my '69 Honda CB450 reassembled, just in time for the last
>>2 days of warm weather.
>>
>>1) I tried to start it and it didn't start, and I had other things to
>>do for 2 or 2.5 hours, and when I got back to it, I saw that I had
>>left the ignition switch on**. This model has two carburetors 2
>>coils, 2 sets of points and 2 condensors. One coil was warm, and it
>>had 1 to 2 thimbles of waxy stuff which had come out of it. Did I
>>ruin the coil? If not yet, will it die in 5 or 10 hours of use? Is
>>there some way to repair the damage I did? (It's not clear I'll be
>>able to find a new set of coils for a 1969 motorcycle.)
>
>I was wrong about this. There are frequent such coils on ebay. I
>thought I had hunted on CB450 and looked at everything ebay had, but I
>must have misrecollected. So since cold weather was coming, I bought
>one even though I wasn't positive I needed it. 15 dollars plus 10
>shipping.
>>
>>2) The voltage
>>was 6 volts using an analog meter, and didnt' seem to be going up.
>
>There were other strange results from my measurements. Partly from
>mild dirt and corrosion which made it hard to make a good contact with
>the surface, but I too often get strange results.
>
> ====>> ??
>
>>3) On the other circuit, I tried to evaluate the other condenser by
>>turning the ignition off and measuring the resistance across the
>>points, which I'm pretty sure is across the condenser. I expected to
>>see the resistance pretty low as the condenser filled and then
>>increace. But the resistance was close to infinity. If I tested
>>right? that means the condensor is open, but that shouldn't keep the
>>cyclinder from firing, right? IIRC, mostly what it means is that the
>>points would pit quickly?? If I can't get the right condensor
>>quickly, what value and type would I need to jerry rig one
>>temporarily?
>
>I found specs that these are about 0.23 uf, microfarads. Pretty big.
>
>Which is why it is possible to use an ohmmeter to test the capacitance
>of these condensors, despite one poster's dubiousness.
>
>I used to do this a lot, so I got the same meter I had used in the
>past, a Lafayette VOM, from about 1971. On the x1K scale, when
>applying the leads, the meter moves from all the way to the left about
>10 degrees to the right, then slowly goes back to the left again.
>
>For the sake of diodes and caps, when I needed new leads for some
>reason, I made some with a double throw, double pole slide switch in
>the middle that enables me to change polarity easily. Flipping the
>switch back and forth would show the same behaviour each time, the
>needle going to the right 10 degrees and then back to the left. This
>means afaik that the capacitor is good. Yes?
Possibly. That doesn't test breakdown voltage for example. It does say
they are not shorted at the low voltage of the meter...
>
>I repeated the test with a Micronta "Range Doubler" analog meter which
>I bought a few years ago used, but which I think was sold by Radio
>Shack in the 70's. The test wasnt' as clear, but it gave similar
>results to the Lafayette meter. 50,000 or 25,000 ohms per volt,
>depending on whether range doubling is on or off.
>
>When removed from the bike and disassembled, it turned out both of my
>old capacitors, and both of the new capacitors were all good, despite
>the indication I got somehow. that one was shorted. I really can't
>imagine what gave the bad reading, since I had 3 layers of moderately
>thick paper separating the points, and the ignition switch was off so
>that end of the circuit was broken, AND at the same time I got
>"shorted" for one capacitor, I got infinity for the other. I probably
>wasn't using the analog meter, but some digital meter, which, unless
>specifically designed for caps, can never measure or indicate
>capacitance, afaik. So I still don't understand how I got shorted
>for a cap that wasn't shorted.
Uh, maybe something else is shorted? Or maybe an intermittant short
that went away when you removed it?
>
>
>>4) There is a wick that lubricates the cam and keeps the rubbing
>>blocks from wearing out. I can't remember what I'm supposed to put on
>>the wick. What do I use, and if they don't still sell it, what do I
>>buy instead? :)
>====>>
>I went looking for cam grease andd they offerred me
>A) Dielectric Connector Protector -- Avoid electrical failure, lock
>out moisture, avoid corrosion.
>B) E.P Antie-seize Engine Assemby Lube, with Moly and Graphite -- work
>s on camshaft bearings... and all areas of rational or sliding metal
>to metal contact.
Absolute NO to selection B! Never, ever!
On selection A, if this is all you can find, use it. Be very careful
not to over apply it however. Real cam lub is quite sticky to prevent
it from being slung off as the cam rotates (and having that slung off
stuff contaminate the points...) Dielectric grease is similar but not
as sticky.
>
>Are either of these going to work? I don't think so, but I got to
>shopping late, spent the daylight hours working on the bike in 74
>degree weather, and the real auto parts store next door wasn't open
>that late.
>
>> (I had trouble remembering this 30 to 20 years ago,
>>too, but I haven't had to worry about it since I've had
>>all-elecctronic ignitions on my car)
>>
>>
>>**If it had started, I would have remembered to turn the ignition off,
>>but since it didn't, I didn't. My fault.
>>
>>BTW, the starter motor worked well, even though I hadn't checked it
>>out, and the kick starter seemed to maybe be working well, or at least
>>differently, even though it would go so far and then stop dead without
>>cranking up till now. The clutch disengaging is working fair, and the
>>throttle doesn't spring back quickly enough, even though I oiled all 3
>>cables (2 carburetors) and the throttle plates moved easily after
>>soaking the carburetors in Permatex.
>
>Although they slowed down in the two weeks after I soaked them until I
>installed them. I had to spray carb cleaner in them to free them up
>again, and I expect this is where the problem is. (Unlike the other
Me, I'd look for new cables if possible. They may never recover. You
can probably hvae them custom fabricated at a reasonable cost.
>parts, I diddn't disassemble this part. I left the butterfly on the
>shaft and left the shaft in the carb. That was a mistake??
I'm always very reluctant to pull the butterfly out unless there is
excessive play/leakage at teh shaft that must be fixed. (that involves
machining out the holes, sleeving them, and a bunch of other PITA
work, so don't do that unless necessary.
>
>Thanks.
>>
>>Remove NOPSAM to email me..
>
>
>Remove NOPSAM to email me..
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