Topic: Won't start and squeeking??? Help!

[papp101]

So I got this baby to run just fine yesterday. Installed the sprocket/clutch cable/drive cover and then went to fire it up again and nothing.

Here is what I have tested - run switch gives continuity, 12v getting to coils. sometimes spark seen between points, sometimes not. Cleaned points contacts with cardboard.

If there's oil on the cam lobe that moves the points (spark advance unit) will that cause a problem?

I'm getting what looks like weak spark at the plugs on both 3 and 4.

Also, I'm hearing some squeeking now while the engine's turning over. I had taken the head and jug off and installed new rings, and done all new gaskets throughout during reassembly. Is it possible I didn't clean thoroughly the oil passageways? I swore I did but you never know.


Any Ideas on what would cause the points to fire intermittently?

Is there a good way to check if I'm getting oil to travel up into the head?

Please help if you have any insight! I've done all the 12v testing I can think of!

[Bob Wessner]

Might help to get assistance if you listed which bike/year/model, etc.

[papp101]

Also, I'd found that the spark advance unit wasn't moving freely, so I took it out and worked it with some oil until it was moving at about 90% (will probably need to replace it) wiped it off and reinstalled. There may still be some oil on the cam lobe.

Does that point where the spring portion of the points contacts the lobe conduct? Could oil there be a problem?

Also I can't tell about the squeeking but my assumption is that it sounds like rings on piston walls. I have not had a chance to thoroughly break in the rings.

1971 cb500k

[papp101]

Identified the squeeking as the stator cover was loose.

Still won't start, had a few spits come out the carbs though.

[TwoTired]

So I got this baby to run just fine yesterday. Installed the sprocket/clutch cable/drive cover and then went to fire it up again and nothing.

It sat for a while?  Were the carbs cleaned?  Or were they just left to soak in new gas after the hiatus?  Might have softened enough of the dried internal deposits to plug up the jets.

If there's oil on the cam lobe that moves the points (spark advance unit) will that cause a problem?

No. The Rubbing block/cam requires lubrication.

Cheers,

[papp101]

Cleaned the carbs yesterday before installing, though the first time gas going through in years may have loosened some stuff up. I'll pull them and get the air hose and wires through the passages.

Carb cleaning finished, checked the fuel passages and jets. Should I have removed the air screws as well? The plugs are wet.



Checking the timing  now.

[Duke McDukiedook]

Yes, check every air and fuel passage in the carbs, if you haven't you have not fully cleaned your carbs.

Could be a bad coil, wire connections, points, condenser, spark plug wires, spark plugs. Checked all those?

[TwoTired]

Did you take the timing advancer apart?  The cam can be assembled 180 out of phase.  Just a thought...

Are your spark plugs black at the tips?

[papp101]

Two tired - you're reading my mind! I checked the timing again and the advancer lobe seems to be pushing the 1-4 points open and closing them almost exactly at the 2-3 mark. I tried to take the spark advancer apart when I had it out but couldn't.

There's that pin to set it on the crank shaft, so how could I have put it back on the bike wrong? Could I have bent it when I was working it back and forth to lube it up?

[TwoTired]

Two tired - you're reading my mind! I checked the timing again and the advancer lobe seems to be pushing the 1-4 points open and closing them almost exactly at the 2-3 mark. I tried to take the spark advancer apart when I had it out but couldn't.

There's that pin to set it on the crank shaft, so how could I have put it back on the bike wrong? Could I have bent it when I was working it back and forth to lube it up?

If you dismantled the advancer assembly, it is possible to reassemble the cam onto the assembly 180 out.  As you say, the assembly must be installed with pin alignment.  So, if the assembly is built wrong, the timing will be 180 out.

However, I think it will work with a backwards assembly if you also swap the blue and yellow wires at the coils.  (not exactly an elegant solution, though)

Cheers,

[papp101]

I was thinking that as well, but then thought how could it have run so well yesterday?

I was using my timing bulb and I think my mistake was thinking the bulb should go OFF when the timing mark was at 1-4 F. Re-reading the book tells me it should go on at that point, and the timing went pretty well from that point. When I adjusted the plate to match these settings I found myself placing it at about a 30 degree difference advanced.

I'll post up after the battery charges and will let you know how it goes!