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Discussion Starter · #1 ·
Working on a '73 CB200 for a friend. This was a running, riding bike until about a month ago. She called me just as I got home from a local bike night and said she broke down. The bike kept cutting off on her. She was able to limp it home and I went a few days later to get the bike.


Got it to my house and checked the plugs and they were good....not fouled. She had JUST installed two new NGK D8EA plugs in an attempt to get it running again. I pulled the sediment bowl on the petcock and the float bowl on the LH carb. Both had clean gas and not trash in them. I checked fuel flow through the petcock and the float valve. But it all back together and put the bike on the charger (battery was working...turning the bike over, anyway). The next day, I noticed the fuel level was a little low and that the petcock was new, so I put it on reserve and the bike started. The trip meter showed 71 miles. "Ah-ha! Aftermarket petcock and high reserve pipe! She was just out of gas!".


Told her to order new points, condenser, and spark plug caps and we'd install them when she came to get the bike. Did that last night, minus the points because the old ones look brand new, and tried to start the bike.
No Go.
It just cranks and cranks and cranks with the occasional cough like it WANTS to start, but it won't.


*We changed the condenser, since a bad condenser can sometimes fail when hot, so I wanted to eliminate that.
*Checked the plugs again. Gave them a quick clean but they didn't really need it.
*Trimmed back spark plug wires and installed new NGK caps.
*Checked the sediment bowl and fuel flow through petcock again.
*Charged battery overnight, but it turned the bike over fine for 15-20 minutes while we tried last night.
*Removed one of the air cleaners. It doesn't look bad and is OEM. When cranking with the air cleaner off, I can see fuel moving through the carb. No change when trying to start with that one filter off.
*Dressed the points. We're getting spark at the points and at both plugs.
*Did the finger over the spark plug hole test and it has compression.

At this point, I'm stumped. We seem to have fuel, air, compression and spark. It just won't run. Tried kicking it. Tried bump starting it.
My next move is to check valve adjustment, timing and actually setting the points rather than just cleaning them. I can't imagine that the timing or valve adjustments are off that bad. I mean, I have compression, and when I got the bike running it ran great. No noises or hesitations or flat spots.
What the heck do I check next?
 

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Sounds to me like you have a good plan. If you remove the plugs after attempting to start are they wet?
 

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Discussion Starter · #4 ·
The plugs eventually get a little gas on them after repeated attempts. I don't THINK that it's not firing because of fouled plugs. This started on one set of plugs and continues with new plugs. There is no difference when the plugs are clean and dry.

Occasionally, I get a little rumble like it wants to do something, but maybe only one revolution. It just turns over and over and over, never really trying to run other than a burble every so often.
The funny thing is, the first day I tried it when I thought it was the reserve, it started right up and ran flawlessly. Parked it for a couple of weeks until she showed up. We changed the plug caps and condenser and now it's doing exactly what she described to me the night it broke down on her.

I'll do valves and timing soon and see if anything jumps out at me.
 

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I had the same issue where everything should have worked and my problem ended up being that the oil slinger cap had come loose from the oil filter so it was no longer pumping oil. You might want to check that out and see if that's it, and just pray that your camshaft and cam bearing are alright because mine are trashed and I'm trying to find parts.
 

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Discussion Starter · #7 ·
* Adjusted the valves today. Found three very loose and one exhaust tight. All are at .002 now.


* Adjusted point gap.


* Checked timing and set it with a light. It seemed to be off. The online Honda manual just says line up the F mark and make the light come on. Her aftermarket manual says to do that and then go one full revolution and set it for the other cylinder. We did this twice and it will NOT align to the mark on both cylinders. You get one or the other. Tried to split the difference, but either way it's off.


* Adjusted cam chain.


* Checked petcock operation, fuel flow, floats, etc., umpteen times.


* Checked for spark at points and plugs. Getting it, but it's weak at the plugs. BUT....we've been cranking this thing to death.


* Pulled carbs. Clean as a whistle. Checked and set floats to 22mm.


The damn thing just won't run. With or without the air filters on. I can see fuel in the carb throats, and I get fuel on my hand when I choke the throat. But pull a plug and it's dry as hell.
I'm truly stumped at this point.
 

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Discussion Starter · #10 ·
Not while I've had it. But I have noticed weak spark.
I'm thinking about a new battery and/or coils at this point, but that doesn't explain why the plugs are dry.

Say I have bad coils....no spark under compression.... wouldn't there be gas on the plugs?
 

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Eliminate the possibility of the points shorting out on the metal cover. Take the cover off and see what happens.
 

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Not while I've had it. But I have noticed weak spark.
I'm thinking about a new battery and/or coils at this point, but that doesn't explain why the plugs are dry.

Say I have bad coils....no spark under compression.... wouldn't there be gas on the plugs?
If the cam timing is off far enough the valve may not be opening enough on the intake stroke to get a solid shot of gas.

Of course if the cam timing was too far off that should show up in the compression test, which you already did,
 

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Discussion Starter · #14 ·
If the cam timing is off far enough the valve may not be opening enough on the intake stroke to get a solid shot of gas.

Of course if the cam timing was too far off that should show up in the compression test, which you already did,
Yes....I'm stumped. It seems like we have everything for it to run: fuel, air spark and compression. It just won't. Barely even makes a cough or rumble. Once out of every several hundred revolutions, and never even enough to think it'll start.

I'm curious about why I seem to have fuel everywhere it needs to be but, after repeated starting attempts, the plugs are dry?
 

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* Checked timing and set it with a light. It seemed to be off. The online Honda manual just says line up the F mark and make the light come on. Her aftermarket manual says to do that and then go one full revolution and set it for the other cylinder. We did this twice and it will NOT align to the mark on both cylinders. You get one or the other. Tried to split the difference, but either way it's off.
WHOA....hold up, the timings set when the the points open not close.
The Light needs to go out on the F, not come on.

Also where was the crank set when you adjusted the valves, ( 3 loose, 1 tight) sounds like one is open, three closed youll need to redo the one that was tight rotating the crank till its closed

You cant check for spark at the points, if the points spark either the condenser's shot or the points are worn or both

Float height is 21mm
 

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Discussion Starter · #16 ·
I followed the directions from the factory manual, which say:

"With test lamp
1. Connect one lead of the test lamp to the contact breaker spring and the other to the engine (ground)
2. Turn on both the main and ignition switches
3. Slowly turn the generator rotor in a counterclockwise direction until the lamp is about to light. Timing is correct if the mar "F" is lined up with the index mark.
4. When adjustment is necessary, loosen the locking screws and rotate the base plate as necessary"

Then, I followed that up with the Clymer, which says:

"2. Place a wrench on the alternator bolt and turn the engine over until the F mark on the alternator rotor aligns with the index pointer.
3. Connect a timing tester to the breaker point terminal and a good ground.
4 Loosen both base plate screws just enough so that the base plate can be moved slightly. Turn the base plate so that the points just begin to open.The test lamp will light exactly at the moment that the F mark on the alternator rotor aligns with the index pointer, if the ignition timing is correct. (italics mine)
5. Tighten base plate screws
6. Recheck adjustment by turning the rotor clockwise slightly, then counterclockwise slowly. The F mark and index should align just as the points open (and the test lamp lights up). Readjust in necessary,
7. To check the remaining cylinder, turn the rotor one full revolution (360 degrees)and perform the preceding steps again.


Re: The valves. I rotated the crank until the intake valve went down then started back up. The I lined up the T mark. Then I checked and made sure both valves were closed (loose at the tappet). Adjusted those two, rotated the engine, did the other two.

You're telling me that you can't see a spark when you watch the points. I've always been able to see spark at the points.
 

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Discussion Starter · #17 ·
And the Clymer manual says 22 mm float height, so that's what I used (the only info I had). Both were off.....25 and 27 mm or so, so even if it's 21mm, I'm now closer than they were.
Float bowls are not low when we remove them.
 

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Discussion Starter · #18 ·
I won't go over everything in detail, but I double-triple-quadruple checked the valves, timing, coil tests, etc., this morning and found...NOTHING.
Started back tracking and decided to put the old condenser back in. The first night it broke down on her, it would run-die-run-die, etc., and that can be a symptom of a failing condenser. As part of the tune up, we replaced it.
Since that was one variable, I put the old one back in...and it fired up instantly! Test ride is good so far, runs and sounds great.
It kicked my ass for a bit, but I think it's fixed!
 

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Discussion Starter · #20 · (Edited)
Then the factory service manual instructions for using a static timing light are wrong.
The manual that's listed on this site as a genuine Honda manual.
And it runs like a top using that method, now that I got rid of the crappy aftermarket condenser.

And the site sponsor Common Motors uses the "light kicks on" method, too.

 
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