Topic: Points Adjustment '75 CB550

[quidger]

The last thing that I wanted to do was to ask this question on the forum that has been discussed ad nauseum, but I have tried every approach that I can think of and I have read the FAQ written by Two Tired and several other related threads about running out of adjusting room on the points plate. I just don't get it and I'm making no progress toward resolving my problem.
The large adjuster plate fits perfectly with no gaps or room for any lateral movement. So I cannot shim the large plate between any of the three mounting posts as is suggested in the FAQ tip on running out of adjusting room.
I measured the new OEM TEC points with a caliper to make sure that they were the same size as the old ones that I am replacing. They are fine.
I loosened the large plate, re-centered it, reset the points and tried again. Same issue - ran out of room to adjust as far as I needed to get the "F" mark aligned.
I dug an extra large plate out of a box of extra parts and mounted the points and condensers on it thinking that there may be some slight warp in the other plate. Same results.
Maybe I'm not understanding the instructional in the FAQ about shimming the large plate against the mounting post that was written by Two Tired.
Any help is appreciated. Getting highly frustrated.
Thanks!

[Spanner 1]

Couple or 3 things..... are your points set @ 14 thou. at the max. lift point of the cam?
Is the advancer unit free and fully turned back ( counter-clock) against it's 'stop' ?
Could the points cam be off center ( would effect 1 set of points more than both).... i.e. any chance the stud holding the points cam is slightly bent ( really need dial guage to check ) ?

Bent points cam stud prolly caused by folks turning motor ( against compression ) with a wrench on the end of the points cam... AAAAH

[Popwood]

+1 on Spanner 1's suggestions. With a new OEM plate and points set up, I'd dig a iittle deeper and check the advancer and look for any run-out on the stud that holds the points cam. You can imagine if there is a slight bend it would play havoc with the points cam greatly exaggerating it's swing.

[TwoTired]

When you check the points plate for lateral play, are the points on the plate?  Are the point's springs preventing lateral motion?

[quidger]

Yes. The points are on the plate when I checked for lateral movement. Should the plate be stripped of the points and condensers to check for lateral movement?

[TwoTired]

Yes. The points are on the plate when I checked for lateral movement. Should the plate be stripped of the points and condensers to check for lateral movement?

Yes, the point springs are pretty strong and may hide the "slop" in the mounting posts.

Cheers,

[quidger]

When I remove the points and condensers I am able to wedge a .005 feeler gauge between the plate and the mount post.

I'm guess that I'm  not sure exactly what I should be looking for on the spark advancer in term of excessive wear. It doesn't appear to be worn and the springs seem to be strong enough. I'm not sure what Popwood is refers to when he says to "look for run out on the stud that holds the points cam".

The only thing that looks to have some slop in it is the large 23MM washer/nut. The cut out in the washer/nut that holds the advancer shaft is worn and has some play but I wouldn't think that it would be an issue once the advancer is bolted firmly into place.

[TwoTired]

When I remove the points and condensers I am able to wedge a .005 feeler gauge between the plate and the mount post.

Assuming that's the "vertical" post, that's what you will need to get the timing back in spec., assuming you choose the correct post that allows the correct gap and moves the timng mark in the beneficial direction.

I'm guess that I'm  not sure exactly what I should be looking for on the spark advancer in term of excessive wear. It doesn't appear to be worn and the springs seem to be strong enough. I'm not sure what Popwood is refers to when he says to "look for run out on the stud that holds the points cam".

RPM causes the timing to advance.  You won't get full timing retardation at 2000 RPM.

Cheers,

[quidger]

I have shimmed the lower right or 5 o'clock position of the three mount post. I think that is the one that will shift things in the right direction. If not, I'll try the other lower post (7 o'clock).

[quidger]

I shimmed the large plate per Two Tired's tutorial and then was able to get 1 & 4 to align with the timing mark. That was the problem and it is now solved. The bike wouldn't even start before and now it fires on the first turn.

Now with the smaller #2 & #3 plate turned all the way to one side I cannot get these to align with the timing mark. Ran out of room for adjustment again. Off just a bit. Haven't dynamically timed yet but even with 2 & 3 not perfect the machine is running pretty good.
Before I shimmed the plate and got 1 & 4 to line up, #2 & #3 were easily brought into alignment.

How do I address the new issue with 2 & 3.

Thanks.

[Spanner 1]

Still think the points cam is out of 'true'

[quidger]

When you refer to the points cam I assume that is the advancer unit. Is that correct?
If so, how would I go about checking to see if it is out of true.

Thanks.

[Spanner 1]

My theory may be premature, actually !!... a little more 'centering' work on the points plate may fix it as you seem to be close.... however, with the points plate removed the points cam/ advancer is accesible and slides off the shaft when you remove the 6mm nut... be careful with the small locating pin behind the advancer..... turn the motor with the start button and observe shaft for any 'wobble'. It's hard to see and really needs a dial guage  set-up to really check it properly IMO. When you consider that skinny little shaft and think about guys using it to turn the motor ( wrench on the hex 'washer') it's not surprising that some may be slightly bent