I have lots to reply about the brass screen, but soon, no time now.
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.)
2) One set of points was open and one was closed. I put a thin piece
of cardboard between the closed points, turned the ignition on again,
and measured the voltage across the points. The circuit is battery
plus terminal - coil - (points/condenser, where these two are in
parallel with each other) - ground - battery negative terminal. So it
seems to me that the voltage should be battery voltage, about 12
volts. Or should it be less until the condenser fills? The voltage
was 6 volts using an analog meter, and didnt' seem to be going up. I
thought, Oh my gosh, I've run down my brand new battery, but when I
checked the voltage there, it was at least 12.5.
BTW, how much damage *did* I do to the battery by running one ignition
coil for 2 to 2.5 hours?
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
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 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.
Remove NOPSAM to email me..
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 ====>>
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
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.
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?
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.
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.
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
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
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??
Blue Streak is one company that makes ignition point sets. They also sell small
tubes of the grease. It's called "Lubricam" and it is specifically for this
purpose. You want to apply such a thin coating that you almost can't see it. Try
a NAPA dealer. They may have to special order it. Forget all the newer autoparts
retailers like AutoZone. You need NAPA for this.
Possibly. That doesn't test breakdown voltage for example. It does say
they are not shorted at the low voltage of the meter...
Uh, maybe something else is shorted? Or maybe an intermittant short
that went away when you removed it?
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
Me, I'd look for new cables if possible. They may never recover. You
can probably hvae them custom fabricated at a reasonable cost.
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.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.