Cam ring capers

[beezalex]

Yes, that's rather typical of old bike owners.

The owners being the old part, that is...

[rocket man]

i will have you know im younger than my BSA by 2 years

[duTch]

 I thought to start a new thread, but this is fairly relevant....good story Richard, I've seen it a few times when I first came along- in fact was one that often came up in searches before I new about the forum....now, on with my hijack

 When I was checking my maggie over to do the assembly timing, I noticed a points gap variation of about .005", but chose to leave it till I'd thought about it and researched a plan and Richards method was about what I had in mind, but with just the dremel, none of that other fancy stuff..!!

 Before doing anything drastic though, I had a thought that maybe the points plate could be sitting a bit askew on the taper(s), so pulled it off, and there was a couple of minor blemishes on the main one near the key.

  Gave it a light scrape clean with a blade, and back on the keyway, but rotated to where there's no pressure on the rubbing heel to offset it.
 Much better, but just fettled it a bit while doing in the tapered screw, and it's within about .001"(for now).
 Seems to be running more even, but still a bit rich.

 Not to say it's totally fixed, but thought it all worth a mention and worth looking at before doing any unnecessary grinding......?

 Cheers for now

[Triton Thrasher]

There was another observer who was a long-time Triumph owner. He was suitably impressed, and said that there was no way he would have the confidence to work his T110 that hard!

Sounds like  he's just careful with his own bike, whatever make or model.

[ianselva]

I have traced my problem of uneven running A7SS to the same problem ,but much worse. I cannot get the gaps nearer than .008 difference. I have tried two cam rings . I am thinking about replacing the whole lot with a Thorspark electronic conversion . Has anybody had any experience of them ?

Cheers

Ian

[RichardL]

Ian,

Take a look at this topic showing a10gf's mag rebuild.  Work your way down to where he discusses and fixes bearing cup eccentricity. I'm not sure this is your problem,  but It may be somrthing you haven't considered.

 http://www.a7a10.net/forum/index.php?topic=1375.0

Richard L.

[ianselva]

I did find the bearing cup was offset but it has just been centralised, and I dont think it be offset enough to correct the points gap differences.

Ian

[duTch]

 With regard to my post on previous page- scraping the whatzit- it didn't work, can't even figure what logic I was using, I think someone slipped something in my tea.
 So I changed the needle jet and it's much better, but still the points have a ~0.005 variation, causing a difference in L/R timing, and a dark patch on the front of r/h plug which makes me wonder if it indicates a timing discrepancy?

 How is the cam ring held in place ? and is it intended to/should it remove easily?? so that I may inspect it properly
 Thanks in advance, duTch
   

[ianselva]

The cam ring should just slide out once you remove the end cap and points.
I had to have my mag completely rebuilt into a spare housing as the points gap difference was too large even after having the bearing re-fitted.
I got a spare housing from Netley Marsh A/j and sent the whole lot off to BrightSpark magnetos. He had to use bits from one set of casings with bits from the other in order to get the armature central so the points gap at both positions was less than 0.002. This made all the difference as the bike now runs properly on both cylinders for the first time and both plugs come out looking the same colour.

Ian

[Briz]

I am mystified as to where all the horses have gone.
Maybe they were a different breed way back when these engines were built and brake tested.
Maybe not as strong as today's horses so there were more required.
Trev.

Its the difference between crank horsepower and rear-wheel horsepower.

[duTch]

Thanks Ian,
        figured maybe like that but mine seems to be held with some kind of goop, and I didn't want to force anything. I forgot to mention it's a auto-advance one, are they same-ish removal, or a 'snugger' fit ??

  (mine was rebuilt (condensor, rewound) a while ago by the legendary (in my area) Les McKiterick, only done ~2000 miles, but don't know if he removed/replaced cam- maybe not)
  cheers

[trevinoz]

Dutch,
              They can be a bugger to get out. Should be a nice snug slding fit but they tend to get corrosion around them.
Usually a spell in the oven will get them moving but you have to take the end off to do it.
 
Trev.

[duTch]

 Thanks Trev, I'll put a bit of thought into it...(a bit hard to believe I know!! )

[duTch]

 Ok so I put some thought in, and then remembered the slide puller......!! a little suck here, and a little suck there...voila(that Italian thing) out it came, just the right amount of tongue lube.....!!
 Was held in with goop, and after a cleanup, found it to be a fairly sloppy fit, ring profile(thickness) ok, but a touch out of round.
Have packed it out with alfoil will see how it goes.

 for the record, it's a #42174B maggie