The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => Lucas, Ignition, Charging, Electrical => Topic started by: cus on 12.01. 2010 08:45

Title: Manual Adv./Ret.
Post by: cus on 12.01. 2010 08:45
G'day All,
Thanks Groily for your reply on fuse blowing, still working on that one.
Went for a ride today, did as always, pulled the ret. lever back a bit
to start, warmed up the bike, took off round the block, then pushed
lever to full adv, but noticed a lack of power & sounding still retarded,
stopped the bike & went to pull the lever, but it had seized up, thought it
might have been the cable, but that seemed O.K. So got it home & took
the cover off the mag., the slipper ring does move a little bit when I pull
the lever, but won't slide around as normal, I'm thinking its something
with the plunger at the end of the cable, but I'm at a bit of a loss

regards, Cus
Title: Re: Manual Adv./Ret.
Post by: groily on 12.01. 2010 10:06
Sometimes the bit on the end of the cable that engages the cam ring can slip out and jam; other times - especially when it's darn cold/damp - the cam ring can seize. The latter especially if the bike has been washed and left damp. Been there done that. Sounds like the former here.
In either case, take end cap off again, get cam ring out (position points so they're not open ie the heel of the moving point isn't against either ramp), unscrew A/R cable from mag then have a good look at the parts. Sometimes the part of the upper surface of the hook that engages the cam ring gets a bit worn and will slip out no matter what you do. In which case, it's either a new bit (or make it), or sometimes you can turn the bit 180 degrees on the cable and mount it so the less-worn side engages. Unlikely that the cam ring's V-shaped cutaway will be messed up (although not impossible) and can sometimes be made better with small file or v fine grinding wheel if you've got one. Make sure there's a bit of lubricated felt in the cut-away slot under the cam ring - there often isn't (and it does make a difference).
Clean cable + mechanism, lightly lubed, a decent spring, and not too much slack in the cable - although you do want it to allow full advance comfortably which it won't if the inner's adjusted too short. Also worth checking the cable again while detached at the mag to be quite sure there isn't a glitch somewhere.
Sometimes it's hard to get the cable end to screw out of or into the mag, depending on the exact mag you've got and the angles involved - but it should come out. If the clearance against the carb(s) or drip plate or anything else is tight, screw the adjuster right in with the cam ring out, while getting the main screw in or out. Worst case, take the points + backplate off, get the bearing housing off the mag with the cable still attached and unscrew it when there's more room, and reassemble the same way. Good luck!
Title: Re: Manual Adv./Ret.
Post by: cus on 12.01. 2010 20:55
Thanks again Groily,
I'm not that familiar with maggies & don't like mucking with them,
this maggie was fully recoed less than 1000 miles ago with new cable,
spring & plunger, so I was a bit baffled why it seized. On your advice I
removed the cam ring, which took some getting out, it had some mild
corrosian on the outside edge surrounding the oil hole, which had locked
it in position, so I cleaned it up with 1200 paper, re-greased both edges,
lubed up the cable & plunger & back in business. It's weird how it seized
all of a sudden though, didn't seem to be getting hard to retard, just
seized, & it wasn't going to budge, I could feel the cable stretching
when trying to free it up, they're weird animals these don't
know what's round the corner!

thanks again, Cus
Title: Re: Manual Adv./Ret.
Post by: groily on 13.01. 2010 07:46
yup, they can be sensitive little things cus. I had a ring seize on one of mine not long ago, after washing the bike (very rare event) and leaving it without having run it to get it dry and warm - and it was also a hell of a fiddle to get it out to clean it. Only takes a little bit of corrosion or other muck to seize them up. Good news that the bits in yours are new-ish. In the current northern winter, every time I walk past the bikes, I operate the AR levers on them a few times to keep things moving, and then leave them in mid-position. They can tend to get a bit sticky at Minus Lots of degrees in a very cold shed. A good idea to have a good rubber sleeve over the cable end and adjuster where it enters the mag body, to keep moisture out, but even in the best-managed places (mine isn't) things will come and bite us. You're lucky you've got riding weather - going stir-crazy here, with snow everywhere and minor roads impassable after yet another good dump last night. It's normally year-round biking here - but not much possible since the new year . . . .