Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board A65 Boyer timing plate ?

Gents,

I can’t post pics so bare with me please.

Was checking the timing on my 66 Lightning “static” while lining up the mark on the stator…5-o’clock, crank tool installed and TDC comp stroke on left cylinder….all good there. I pulled the timing cover “Boyer ignition “ I noticed the timing marks on the plate are 180* off from what the instructions show. Boyer shows the timing holes at 7 o’clock position while looking at them and mine are at 2 o’clock? After looking at some other bikes on line and there’s are different than mine too. Bike runs fine but did not know if this is of concern or not?



Hope this makes sense?

Knowing how this works, I would theorize that it makes no difference.

It also makes no difference whether the left cylinder or the right cylinder is on the compression stroke. The Boyer ignition fires both cylinders on every up-stroke, although one cylinder is on the exhaust stroke; this is what's called a "wasted spark".

The two coils on the pickup plate are actually one coil, electrically speaking; that is, they are connected in series. The two magnets on the rotor pass the coils on every up-stroke. The function could be accomplished with only one coil, but with less effectiveness (a weaker signal to the ignition module).

It doesn't matter because what actually matters is the degrees of rotation between the rotor magnet and the pickup plate stud. Since the rotor can be installed in any orientation, as long as the are rotated relative to each other and the dot peeks out the correct (anticlockwise) hole you're fine; this ensures that the two parts are timed to one another.

Obviously, installing it as described in the documentation helps prevent future confusion.

Thanks for the replies. I know I overthought this as I usually do but better safe than sorry. 👍👍

Nate
Mark's comments are spot on. It makes no difference. I would time my bikes by one of several means but always would road test for the best results. Advancing the spark until it pings under hard acceleration and then backing off a tad. Fuel makes a difference. I usually ran 93 octane ethanol laced fuel.

Mr Mike

Nate, you can post photos if you first upload them to a photo Hosting site. I use postimages.org. After you upload, display photo, click on "SHARE", then COPY the URL labeled "hotlink for forums" and PASTE in your post.

If you become a life member, you can post pictures directly from your computer.

Thanks mr mike, I know we talked not to long ago about fuel and that did make a difference…100 octane worked well. I should have called you before posting 😂👍😂 all good now.

Thanks everyone else and I should just do a life membership.

I have something to add about the timing of Boyer analogue systems that is very important and I haven't seen it mentioned in discussion forums but I'm sure it has cropped up somewhere. About 30 years ago I decided to upgrade my OIF A65 to a Boyer system. Fitted it and fired it up and checked the timing with a strobe. It didn't advance but it retarded instead. It was working backwards as engine rpm increased. This was before the days of the internet so I was on my own with the problem. I wondered if I had been supplied with a unit designed for an engine spinning in the opposite direction to mine. After some head scratcing, I came up with a solution. I removed the rotor magnets and turned them round 180 degrees so that the magnetic poles were pointing in the opposite directions to as supplied. It solved the problem and worked perfectly for decades. I concluded that the magets on the rotor had been fitted the wrong way round during manufacture. My assumption was false but it took me over 20 years to discover what the real problem was. About 10 years ago I did a major rebuild and fitted a new wiring harness. I noticed that the black/white and black/yellow wires from the Boyer stator plate were connected the wrong way round to the old harness. I connected them the correct way on the new harness. I assumed that it wouldn't make any difference as it wouldn't with the old points system as long as the points rotor was displaced 180 degrees. When checking the timing with a stobe again, the old problem of retarding instead of advancing came back. I switched the wires over and it fixed the problem. So the problem was that 30 years ago I fitted the unit incorrectly. I connected the black/white wire form the stator to the black/yellow of the harness and vice versa. As mentioned, I assumed it wouldn't matter as a Boyer works on a wasted spark system but it does matter. In the correct configuration, it advances as rpm increases and if connected incorrectly it retards with increasing rpm. As mentioned, I didn't think it would matter but it does and it took me 20 years to discover this by accident. By switching the magents around, I had fixed a problem of my own making. I can't help thinking that I'm not the only one to make this mistake and there are quite a few systems out there that are retarding instead of advancing.

That's odd, usually when the pickup wires are reversed the engine won't even start.
I ran into a curiosity once. When I bought my A65 it had a Sparx EI. After too many episodes of having to tighten the goofy little nuts which they use to connect the wires to the pickup plate, I replaced that with one from a Boyer. The magnets on the two systems are opposite polarity, so I had to connect the wires backward for it to work.

BTW: I always found that timing a BSA using the CCW holes in the plate resulted in advanced timing once checked with a strobe. Maybe they think that both time at the 38 BTDC of the Triumph?

JCC in Essex, liked your post. Sounds a little like myself and especially with a positive ground although I would be chicken to smoke it. Also, as far as making power at higher revs with 30 some degree ATC ignition, no way. Maybe make 15 HP with a tailwind.

I just rebuilt my A65T and installed a Boyer 4 system. It will not start for anything.
I have gone through all the Boyer static checks. Everything checks out fine..
I have spark when the plug is lying on the exhaust pipe.

Is it possible the magnets are backwards? David, you mentioned that the bike won't start with the trigger leads reversed.?

Getting very frustrated. (Tired if kicking...)

Steven, when you say everything checks out fine and sparks with the plug removed there is an assumption that the spark is timed on the compression stroke near TDC. If this is so then a shot of starting ether will confirm.

I think you missed the gist of David's post - his magnets weren't backwards, he had reversed the black/yellow and black/white leads. This is certainly something to check, but having eliminated that, I would say if you have spark and it won't start, then the timing must be off (assuming no fuel problem).

Did you position the crank at 34 degrees BTDC and line up the dot on the magnet with the correct (counter clockwise rotation) hole in the plate? (Sadly, they labeled the holes on the BACK side of the plate!)

Just to add a little more of my experience of my particular issue, in relation to this thread..... At one point, I did have an on-line conversation with tech support from Boyer regarding the importance of North/South magnet polarity reversal and its importance with respect to ignition advance . After a few email exchanges, my conclusion was that their tech support guy had his understanding of North/South polarity completely back-to-front. I thought that was a little worrying. Trust me, I know quite a lot about magnetism and a correct understanding of how North/South poles are differentiated is fairly basic stuff and on page 2 of the education manual.

Just to reiterate my comment, no one, including David, has reported that a Boyer kit came with the magnet polarity reversed. Consequently, this is not something I would suspect as the source of Nate's problem.

I should have responded and sorry I haven’t posted pictures. The magnets are in good sort. The bike runs great but when I pulled the timing cover off “don’t remember why” I noticed the timing holes were located at the 7-8 o’clock position instead of the 2-3 o’clock position as per the instructions.

Knowing how the bike fires and from all of your knowledge I guess it doesn’t really matter as long as the white dot lines up in the correct spot. The instructions show the white dot at the 8 o’clock position and mines shows at the 3 o’clock position.

Sorry for any confusion on this.

My wires where what I was checking to make sure nothing was chaffing as my Commando did at one time.

Right, it should make no difference, but unless I missed something, this is the first I've read that the bike is running now.

Mark,

Bike is running and has been running fine.

Thanks.