Topic: '72 500 Four 9.9 Volts No Spark

[Dr. Frankenstein]

Here's what I just did - I got everything sorted the way you said, but still I got nothing. See pic. I followed all the testing procedures from Common Motor Collective on this video here -

and it looks like BOTH my coils are defective. I feel a strongly worded letter to the vendor coming on.   

I also tested continuity through the points as seen in the video at 3:53, and my test light stayed on the whole time, so something is definitely not right here. It did pass all the other tests except the functionality of the ignition coil test at 10:22 - I just can't believe that ALL my coils, points and condensers, which are NEW, are all bad. That makes me think it's something I'm not doing right, because in 25 years of refurbishing bikes I've never had that happen, usually it's something stupid I've overlooked or forgotten - still, I guess it could happen!

[bryanj]

If the test light stays on either the points are not opening, the wiring to points is shorted to ground or the wiring of points, condenser lead is wrong

[Dr. Frankenstein]

Hmmmm...."or the wiring of points, condenser lead is wrong." I need to investigate that a bit more...on the points that were on the bike originally, the two leads for each condenser were touching the prong for the wire so I put them in that way - I thought that looked weird to begin with...those two prongs for the points and condenser should be separated when they go back in, yes? This bike sat for years in a shed, so I have no idea what the PO may have done.

Update - I am happier to report that seems to have been the problem - I separated the prongs on the points and got a pretty weak spark on 2, 3 and 4, but #1 was a no-show...I've been cranking the bike for a bit, so the voltage has probably dropped some. I'll recharge and test again. 

[denward17]

Hmmmm...."or the wiring of points, condenser lead is wrong." I need to investigate that a bit more...on the points that were on the bike originally, the two leads were touching so I put them in that way - those two prongs for the points and condenser should be separated when they go back in, yes?

I don't think it matters, just make sure they are not touching the bracket of the points.

[Dr. Frankenstein]

See 'Update' above...

I'm pretty sure these are 3 Ohm coils; 5 ohm coils would give me a hotter spark, yes?  Also, I went back and checked again, and I DO have weak spark through #1, but I also am getting a tingle through the Start switch...granted, the plugs are all out, and those acts as the ground - but is something shorting here? I've never felt electricity through the kill switch before. It's not bad, but you can certainly feel it! Tingle Tingle Tingle! 

[Ozzybud]

Great to hear that you are making progress. Do you have the OEM Points and Condensers?  If yes out them back in.

[Dr. Frankenstein]

One of the reasons I changed them was because they were pretty pitted and sparking - of what benefit would this be? 

[Ozzybud]

The aftermarket ones are poo.   If they are sparking it's a sign the condenser is bad. Try and find some good or NOS originals.

[Ozzybud]

The whole honda plate is $86

https://www.ebay.com/itm/276697236682?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=9tS-prIxR-W&sssrc=4429486&ssuid=t3TSanHgRTi&var=&widget_ver=artemis&media=COPY

[Ozzybud]

NOS Honda condensers

https://www.ebay.com/itm/321886303869?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=_Mr7oZObTey&sssrc=4429486&ssuid=t3TSanHgRTi&var=&widget_ver=artemis&media=COPY

[newday777]

Neither of those are for your 500/4

[newday777]

Get them from the link in post 14. Save yourself a lot of trouble and wasted money.

[Ozzybud]

Neither of those are for your 500/4

My mistake.. not sure what Schematics/part numbers I grabbed off CMSNL

[bryanj]

If you get the complete plate it even has the wires that connect by the rear brakelight switch so you cant get the points/condensers/wires position wrong

[Dr. Frankenstein]

Oh, where's the fun in that??   Speaking of which, while we're on the subject of wiring, can somebody please send me a pic of the proper connections for the blinkers in the headlight bucket? My right-rear blinker is hooked up correctly in the back but doesn't want to work with the right-front. The bulb is fine, and I've got continuity through all the wires of the right rear blinker, from the rear connections up to the headlight bucket, but it doesn't want to come on and I think it's a wrong connection, but I don't know where.

[bryanj]

If its a US model the front has 2 wires and a 5/21 bulb, the wires are blue and blue with white stripe for one side the orange and orange with white stripe for the other, dont ask which is rh or lh i can never remember

[Ozzybud]

If its a US model the front has 2 wires and a 5/21 bulb, the wires are blue and blue with white stripe for one side the orange and orange with white stripe for the other, dont ask which is rh or lh i can never remember

The us model CB500 in 1972 did not have running lights so there is only light blue for the right and orange for the left.
If there is 2 wires going to the blinker the other one is green for the ground.

here is a pic of my CB350F  should be similar. mine are grounded thru the headlight ears and bolts. So 1 wire