Timing unit with Boyer question

Well, I've had a productive day in the garage today, I got the head fully torn apart, and got the barrels off as well. I was going to take off the timing cover until this question arose. In the below picture there are the magnets for the Boyer my dad put on the bike back in '70 something. I'm wondering if the case, or the wheel that the magnets are on need to be marked in some way, as they are connected to the camshaft. Or if anything else in the picture needs to be marked for assembly later on. Anything will help, thanks.

You shouldn't need to mark the rotor and you'll find a set up sheet on this;

http://boyerbransden.com/instructions.html

Cash

Thanks, that's exactly what I need

Unlike Triumphs that have an alignment pin, the Norton is a slip fit and needs to be hand-aligned by the instructions.

Thanks, hopefully itll go back together easily

mattthomas4444 said:

Thanks, hopefully itll go back together easily

Click to expand...

The movable stator plate allows one to estimate the position of the rotor installation, snug it down, then dial in the timing by moving the stator plate on its mounting posts.

So, when reassembling, turn the motor to 31 degrees Before Top Dead Center, put your magnetic rotor onto the cam taper so it is horizontal (although I have better results with it installed *slightly* more clockwise - like 9:30/3:30), then install your stator and line the hole with the dot on the magnet. At this point you should be fairly close to timed - close enough to start the bike, anyway.

Warm up the bike and rotate the stator until you get 31 degrees at 5000rpm with a strobe. You must rev to 5k as the Boyer keeps advancing until then.

And if you want to get fancy, see if Greg (NorBsa on this list) has one of his really trick rotors to run. I run it.

Here's a picture or two.

They look very well made, but what advantage do they give?

Cash

Well a few old stock ones have flown apart on race bikes. But for the most part many are very old and still in use. A magnet glued and screwed to steel in a hot spot, well over time the magnets get weak. The new design has a shorter, stronger signal than the stock one. Aluminum sheds heat way faster than steel. And it’s lighter out on the end of your cam. About the same price as stock piece.

I may be able to actually contribute something here.... As from the Norton owners club of NSW. (Aust.) Re Boyer Bransden... Short version... Because your wheels are jumping off the ground at 5000 rpm and the bike has exited the shed door... Try these...3000 rpm/22.8 or 23 deg....3500 rpm/26.1 or 26 deg... 4000 rpm/28 deg...4500 rpm/30 deg...5000 rpm/31 deg... I gave this info to my usual M/C Auto Elecky when I got him to check mine after setting myself, by the book, and he was suitably impressed.

norbsa48503 said:

Well a few old stock ones have flown apart on race bikes. But for the most part many are very old and still in use. A magnet glued and screwed to steel in a hot spot, well over time the magnets get weak. The new design has a shorter, stronger signal than the stock one. Aluminum sheds heat way faster than steel. And it’s lighter out on the end of your cam. About the same price as stock piece.

Click to expand...

norbsa,

Does the signal short duration and strength change the advance curve/line ?
I've got a friend who's Mk3 when set staticly shows 24 to 30 deg of advance when checked at tickover no matter what Boyer is tried. I can only assume the rotor magnets on that motor are sitting farther into the pins. :?

Thanks,
Cash

A signal is a signal. When I first started to do these I had had hope for even more down low power but once the black box has its signal it does what it does. I do know that it takes nothing away from power on a dyno but it does not seem to gain any from the better magnets. The relative timing may need some retarding from the older weaker unit. The pieces are very accurately made on c&c equipment. Just a better than average replacement piece, and one less worry knowing some old stockers have failed in extreme conditions.

norbsa,

I'm sure the advance is all down to the signal current spike. The stronger and the faster the magnet the bigger and wider the spike. With the Anologue Boyer, as the width increases with revs the more advance you get. Seems quite crude but clearly works OK. A stronger reliable signal will help I'm sure, I just thought there might have been a subtle change in the advance.

Many thanks,

Cash