Topic: 1972 CB500 Restoration, points & timing question, spark advancer info

[IrocRuss]

I have a timing question but first wanted to give some info I learned on the spark advancer for future reference.  I removed the spark advancer thinking I had a picture to show the timing mark orientation.  I took it apart and after the fact, I realized I didn't have picture, and the shop manual doesn't detail taking advancer apart.  Searching here and on YouTube, it was suggested the advancer cam mark should lineup with a hole in the advancer body.  Well I found this not to be 100% true on all advancers.  The 323 I have, lines up with a stamping on the 2-3 side of advancer, which is 180 degress out from the hole which is on the 1-4 side of the advancer.  I found a picture in the Honda shop manual, fig 279 on page 92 that is you get a magnifying glass, you can see the advance mark is not on the same side as the hole that was mentioned to line up mark with.  I have include 2 pictures of my advancer and pointed out timing mark, stamped icon on 2-3 side, and hole on 1-4 oposite side of advancer.

Now on the points, condenser and timing.  I refurbished this  72CB500 for my wife's cousin in 2020.  I replaced the points and condenser with aftermarket ones from an Ebay company, parts were made in Taiwan.  Long story short, the owner didn't hardly ride it, and after 2 years, was only firing on 2 or 3 cylinders.  Thought forsure it was carb problems, because he didn't knoe about ethanol gas and the problems it causes sitting to long.  I counted out points and condenser because the had less than 500 miles on them.  THe carbs did have some problems, but after I cleaned them, the bike ran better but was still missing.  I decided to check the electrical just to eliminate it as a problem.  Well the problem was a condenser totally failed, point were sparking like crazy and when I test capacitance, it was totally shorted.  I bought 2 new condensers from K&L, hoping they may be better quality, and came across some new Honda OEM, TEC points on Ebay, so I decided to replace the Taiwan points with OEM.
I got the point gapped and timing set statically, and than fine tuned with a dwell meter and timing light.  The dwell on my Craftsman dwell meter in 4 cylinder mode is ~48-49 degress.  This corrolates to about 0.011-0.012" gap, which is on the tight side of range.  My problem is that the 1-4 timing is pretty close to the "F" mark, but the 2-3 is significantly off, to far advanced.  Both of the main points plate for 1-4 and the secondary plate for the 2-3 cylinders are up against the end of slots, the wont move any farther.  I played with the dwell, and with more dwell (smaller point gap) I can get the timing a little closer, but I didn't want the gap any smaller than the 0.011" that I have so I put it back to where it was.  THe bike starts and seems to rev fine and sounds good, I just didn't think I should ride it with the 2-3 timing that far off.  Any suggestions on this, FYI the main points plate is the OEM, not aftermarket.  Has anyone tried to file out the end of slots to get a little more adjustability?  Any suggestions appreciated.

[Kevnz]

I have heard of people filing the slots, but I've always managed to get the timing right by juggling the points gaps. Both may be at the extreme end of permissible range, but still within.

[Deltarider]

There are two types of advancers used by Honda, the TEC (TOYO) ones or Hitachi. See below for how the cam should be oriented. I believe that with a Hitachi the mark on the rim has to be opposite the Hitachi logo. If you happen to have the cam oriented incorrectly, you could also swap the blue and yellow wires and be done with it. It's no big thing. Just remember it or make note of it.
By using OEM parts, you can start by having all the adjustables in the middle of their ranges. Mine always are. Realise that there can be some play when you install the complete plate. Therefore, to facilitate easy installation, I suggest to temporarily have pieces of an old credit card between the points (minimum 0,4 mm), this to avoid the spring's pressure to interfere.
Your gaps are a bit tight. Realise that in use points gaps tend to decrease over time. You can anticipate by setting them not too tight when you fit new ones.

[Deltarider]

Addition to my reply above. Here a pic of mine (OEM). Everything almost right in the middle of the adjustment range.

[IrocRuss]

There are two types of advancers used by Honda, the TEC (TOYO) ones or Hitachi. See below for how the cam should be oriented. I believe that with a Hitachi the mark on the rim has to be opposite the Hitachi logo. If you happen to have the cam oriented incorrectly, you could also swap the blue and yellow wires and be done with it. It's no big thing. Just remember it or make note of it.
By using OEM parts, you can start by having all the adjustables in the middle of their ranges. Mine always are. Realise that there can be some play when you install the complete plate. Therefore, to facilitate easy installation, I suggest to temporarily have pieces of an old credit card between the points (minimum 0,4 mm), this to avoid the spring's pressure to interfere.
Your gaps are a bit tight. Realise that in use points gaps tend to decrease over time. You can anticipate by setting them not too tight when you fit new ones.

The reason I wanted to mention the advancer is that all of the info I saw suggested that the timing mark must be lined up with the hole, which holds true for the TEC.  But on the Hitachi spark advancer the timing mark lines up with the Logo.  I pulled the picture out of the manual and found another image of the Hitachi advancer.  It is difficult to see the Logo, but in my paper copy manual I can see it with magnifiers.  Also, I think the other image shows the Logo better on the 2-3 side that the timing mark lines up with.  You can see that the timing mark is 180 degrees from the hole on the 1-4 side.  The confirmation to this is the bike starts and revs fine.  When I worked on this back in 2020, I had removed the coils for testing, and put the primary leads on backward.  The bike backfired but wouldn't start. Switched wires back to correct position and bike started.  So assuming I had the advancer 180 degrees off, I don't think the bike would start, idle and rev smoothly like it is.

Back to my real question about the timing.  First off, this bike was inherited in 2019 from the original owner, only had 6700 miles on it.  The point backing plate looks to be an original Hitachi. The plate fits very snugly in casing, no slop like I've read with some aftermarket backing plates.  When I had installed the aftermarket points in 2020, I had this same issue with both backing plates 1-4 and 2-3, being at end travel in slot.  I think 2-3 was off but not as much as the new Hitachi points I just installed now.  I have been playing around with this for a couple of days now, changing gaps and playing with timing, nothing seems to get timing closer on 2-3.  Using your first picture that shows the advancer marks and equivalent degrees, I would guess my 1-4 to be maybe 6 degrees before TDC, and 2-3 more like 10-12 degrees before TDC at 1000rpm. I'm just looking for anyone that has experienced this, and what they did to remedy this or other suggestions.  Or should I just ride it as is and see how it performs on street?

[dave500]

looks like this on TEC advancers.

[Deltarider]

BTW, what would be the ideal oil or grease?

[robvangulik]

I used sewingmachine oil (naaimachine olie ) some 10 years ago, and never had to lube it again since.

[Deltarider]

I wonder if your Craftsman dwell meter has measured degrees dwell or maybe % Duty Cycle. Also some stroboscopic timing lights give more reliable results when powered by an external battery. Are you sure you have installed the points correctly?

[IrocRuss]

I wonder if your Craftsman dwell meter has measured degrees dwell or maybe % Duty Cycle. Also some stroboscopic timing lights give more reliable results when powered by an external battery. Are you sure you have installed the points correctly?

I am at a loss for words.  I thought I tried moving timing plates the other day when I first posted this, to the left side of slot and the timing was always too far advanced but got closer at the right end of slot.  The next day I remembered I took a picture of the timing plate that was original as I received in 2020 (TimingOrig attached).  I was like how could just changing the points make the plate shift that much.  I ended up lossening plate and moving it back and forth, removed the advancer bolt and large hex washer to find timing mark on cam, that's referenced with a black Sharpie line, and put things back together.  I placed the plate in middle of slot, tightened and checked the timing and dwell.  To my amazement, the timing on 1-4 was almost spot on and dwell right at 46deg. I made a slight adjustment and then checked 2-3, and it was off a little more, but got the dwell set to ~48 and timing was right on. I checked point gaps (adjusted dwell dynamically while running) after the fact, and got between 0.013 and 0.014", all good.  So just taken things apart and starting a new day with a clear head, the timing is as shown in the attached timing picture.  You can see a black mark where the plate lined up with the top screw and aluminum support above when I changed points in 2020.  I didn't take a picture of plate that was totally at end of travel the other day.  I wonder if the spark advancer has enough play and shifted after I reassembled because the plate fits nice and tight?  Doesn't matter, it's good for now.

I attached a picture of my dwell meter and timing light, which I bought new back in the 70's when I was taking shop auto mechanics classes at a community college.  Dwell meter is in degrees.  I'm looked at the timing light manual for power consumption, it didn't list any.  Both seem to work fine and make fine tuning much easier.  I don't think the timing light on bike battery is a problem though, I have a new battery with more cracking amps than the original, and the alternator is putting out over 14vdc.

[Deltarider]

What you've described, illustrates what I've been repeating for years. In practical all cases (re)adjusting the points gaps is all what it takes to (re)set the ignition timing. For anyone who has attended classes in basic math, it's perfectly understandable that just slightly shifting the breakerpoints, will result in a far bigger effect in mm the further you move away from the centre towards the outer edge of the plate. What too many do, is, once they've laid their hands on a manual, perform a full reset of everything. They don't realise that's a full description of what is needed, when everything has been removed and taken apart. Once fastened, the three crossheads will not allow the plate to move ever. The same goes for the two crossheads that lock the 2+3 plate. All what changes in use, is taking place at the breakerpoints.
In your case, once satisfied with the timing, write down the dwell numbers for future reference. When your timing is off many, many miles later, you've only to readjust the breakerpoints to the dwell they had before. And OEM breakerpoints live tens of thousands of miles. Just lube that little felt every now and then.

[IrocRuss]

While I appreciate what you may have been saying for years, nobody is going to know that unless they accidently run across one of your post from the past.  I am not an avid Honda SOHC person/owner, so I have not frequented this forum until 2020 when I needed information, so thank you for your input.  People at some point need to take points plate off to grease the cam on the spark advancer, that's one of the reasons I took points plate off.  Also I'm sure since you've been here a while, you probably know that the aftermarket points and condensers from Taiwan and China aren't that great of quality, making adjustment even harder.  The Taiwan points I put in in 2020, the firing mark on one of the sets of points was very unsteady.  The new TEC Honda Points that I was lucky enough to find, seem much better (less play, tighter tolerances) and the firing point is very steady.  So if I'm around next time maintenance is needed from my inlaw who owns the bike, I will try to remember not to move the plate.  Problem is my memory isn't what it used to be.   Another kind of sticky point to me is the original manual I have isn't that detailed on everything, just makes tuning that much harder.  Spark advancer maintenance specific example.

Hopefully this post helps the next guy having tuning issues.