Topic: Ran out of timing adjustment

[Heirborn]

I was trying to set the timing on my '70 cb750 and ran out of adjustment. got 1-4 ok, went to adjust 2-3 and was not able to get it timed. I checked the FAQ and this is what I found.

Help! There is no more adjustment room on my adjuster plate, what do I do?
The gap in the points will affect the timing at F'. If you've run out of room on adjuster plate I would try re-gapping the points. Try a greater gap (.017) and see how this affects. When is the plug firing? I've only timed my bike once without a timing light. The method I was shown was to pull #4 plug, re-attach it to plug lead and ground tip of plug against the engine cooling fin, Then slowly rotate engine until plug sparks. note position on timing plate and adjust. When I did this I noticed that the plug firing did not correspond exactly with the point opening. Hope this helps.

Any other direction? Bike runs pretty good but I have to believe it will run even better when I get it "on the money".

[Dennis]

Sometimes the mounting plate for the points is a slightly loose fit on the engine case. When you loosen the 3 screws to time the 1-4 points the entire plate moves slightly. There is a post regarding that subject here somewhere. search around.
If you are running out of adjustment it is usually a problem with the point gap or something worn in the points assembly. You didn't tell us about the age or milage on the points. 
But if it runs as well as you say, it sounds like a gap adjustment so that you can correct the timing.

[Paul]

In my expierience
These plates work well set up with both sides at centre point of adjustment......Provided everything else is also set up correct. Gaps etc. then the adjustment should be minimal. I had run out of room also but on a re-check...I wasn't set up right initially..the point gaps I adjusted to 100% but...I wasn't at the Highest point.
easy for me to say though..

[damn_yankee]

I had the same thing happen initially when I tried to time my 750 K8. The manual I had was not clear so I did not adjust the points at the high point on the cam. There is no mark for the high point so you must observe the point opening/closing to get it right. Once you get the position on the cam right it should time fine.

Jeff

[cd811]

do a search...july 23...static timing...
twotired has the answer
his procedure works good...takes the slack out @ points plate and plate housing
it needs to be in FAQ

[amattel]

I bought a dwell meter for $15 on ebay and it is really easy to set the gap with it.  One screwdriver on the lock screw and the other as a lever for the adjustment notch...  with the meter hooked up I was able to dial it right in then lock it down.

Adam

[gaijin]

hum, I ran into this problem too after I just recently replaced my points. My timing is too far advanced, and I've run out of adjustment. I've even closed the points gap a little bit, about as much as I dare, and it's still too advanced. I'm not sure what to try next, except perhaps an electronic ignition 

[damn_yankee]

check the advance mechanism and the two springs on it.

[FondaHonda]

I have the same problem but mine are aftermarket electronic points evidently. It is encased in rubber where the points should be. I've turned mine as far counterclockwise as they will go and it still idles roughly. I remember when working on older cars the distributor could be "off a notch" and you would have to pull the distributor and turn it a notch to get things right  I don't know if this is a possibility on the sohc4. If you find the answer I hope you will post it. I will do the same.

[Heirborn]

I have not had the time to monkey with it since my post...won't be until Saturday. 

[gaijin]

I pulled the points plate off while I was monkeying around to check the advance springs, and they seemed fine. I guess I could try replacing them, since I'm out of ideas, and I don't have a solid 'test' to make sure they're ok.

[Jonesy]

There were usually 2 sets of marks on the advancer: one set for the timing at idle, the other for full advance. With a strobe timing light, when the timing is set at idle you can rev the bike up to around 3,000RPM and watch the timing marks move. At full advance the second set of marks should line up with the timing pointer.

I've found sometimes the advancer mechanism is worn and the cam becomes sloppy on the shaft, making timing a nightmare to set. Something else to check.

[TwoTired]

I posted this before and have made it a FAQ submission.

If you remove the points from the plates and loosen all three large plate mounting screws, you will find that that large plate will move some distance radially on the mount posts machined into the engine case.  This movement is why you run out of adjustment range, as some plates are different diameters, and some engines have been machined to a different tollerance limit.  The spring pressures of the points pushes the plate in the opposite direction against the mount post. This puts both points in a position relative to where adjustment range is limited.
What to do.  While you have the points removed from the plate (thus all spring tension) and all three mount screws lossened, find the largest feeler gauge that will insert in the gap between mount post and large breaker plate. This is also the point gap error and directly impacts timing.  Reinstall the 1-4 points, set the gap and the 1-4 static time with the feeler gauge still inserted in the lower right mount post to breaker plate gap.  I sacrificed a feeler blade and cut one in an L shape to fit under the mount screw washer, so it wouldn't fall out during plate rotation. This way I can change the 1-4 timing while the bike is running (dynamic timing) or not (static timing).  In my experience, this brought the adjustment slot for both 1-4 and 2-3 points into an acceptable adjustment range.
How did I figure this out?  Well, the bike showed me this problem.  One day, while trying to dynamically time the engine, I had all three mountplate screws loosend while the engine was running.  It was then I could see the whole friggin plate moving around in the engine posts.  Dwell readings were all over the place, too, depending on which mount screw I tightened first or when and where the engine crankshaft was positioned when a mount screw was tighened.  Putting the plate in a stable position eliminated all the variability of time and dwell.  Then I found that if selected the right post to remove the excessive plate movement, the adjustment ranges of the slots were more than adequate.  So, I made a new tool, and, added it's use during the adjustment procedure.
Life is good.

[SteveD CB500F]

I posted this before and have made it a FAQ submission.

And I put it the Ignition FAQs this morning.

From now on all we have to do is type "look in the FAQs" (takes less time...)

[cd811]

thanks for coming to the rescue twotired.
I knew you could explain it a lot better than I could.
and it works great!!!!!!