Strobe light question

Hi there,

I'm looking for info on how critical it is to set timing with a strobe light if you're running a Boyer ignition. Is it absolutely necessary? I'm mainly interested in never experiencing kickback . I want the bike to run great too obviously, but mainly I want to be confident that my foot isn't going to get torn off when I want to start her up and go for a ride.

Thanks a lot!

Supercat said:

Hi there,

I'm looking for info on how critical it is to set timing with a strobe light if you're running a Boyer ignition. Is it absolutely necessary? I'm mainly interested in never experiencing kickback . I want the bike to run great too obviously, but mainly I want to be confident that my foot isn't going to get torn off when I want to start her up and go for a ride.

Thanks a lot!

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The main thing with a Boyer is making sure you have 12 volts at the igniter,
Maybe fit one of those small volt meters somewhere so you can take a look before kicking it over

Awesome, thanks Baz! When I got the bike running last year she would run good and never kick back as long as she was getting 12 or more volts. The only time I had issues was when my connections weren't good and I was getting less than 12 volts. Then she would kick back pretty much every time. Now that I've got the wiring re-done I'm getting well over 12 volts to the hot wire going to the ignition all the time, and I'm happy to check that regularly for piece of mind. If that's all I need to do to avoid kickback then I'll probably pass on purchasing a strobe light for the time being. I'm about to order a few things for the bike and would get that tool if it's necessary, but if my feet/legs will be ok without it I'll hold off on that for now.

Supercat said:

I'm looking for info on how critical it is to set timing with a strobe light if you're running a Boyer ignition. Is it absolutely necessary?

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You won't know if it's set accurately if you don't strobe it as the 'static' setting is only intended to set the ignition close enough to allow the engine to be started.

A strobe light can be purchased for as little as $15!!!! Do it before you hole a piston or simply have poor performance.

Sorry I didn't realize you never had a strobe lamp
As LAB says it's the only way to set up a Boyer ,maybe have a look on eBay ,a lot of times you will find stuff like that going cheep because people don't use them much anymore they are not needed on modern vehicles
If you buy one it's best to get a sun type one IE one that runs off the bikes battery not the HT lead powered ones as they are very hard to see in my experience
It's also easier with an assistant to do this
Cheers

Thanks guys. Alright, I'll invest in a strobe light. I'm going to need to get a piston stop tool too in that case. I could make one, but it looks like just purchasing one is probably at least as economical, and I won't save any time making one since I'll need to wait for the strobe light to come in anyway. Better to do it right. I don't want to wreck anything at this stage, and these tools are good to have anyway.

Supercat said:

Thanks guys. Alright, I'll invest in a strobe light. I'm going to need to get a piston stop tool too in that case. I could make one, but it looks like just purchasing one is probably at least as economical, and I won't save any time making one since I'll need to wait for the strobe light to come in anyway. Better to do it right. I don't want to wreck anything at this stage, and these tools are good to have anyway.

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If you are buying a piston stop I assume you are doing that in conjunction with a timing disc to check the timing marks you have on your alternator rotor?
If not then you won't need a piston stop

Supercat, as has been pointed out, the Boyer instructions tell how to rough adjust the timing so you can get the bike started, and a timing light will help you fine adjust the timing. For most folks, that is good enough.

However, if you think about the fact that the engine is approaching 50 years old, has had countless changes by previous owners, and is running modern garbage gas, why would you expect a couple of stamped factory witness marks to give you the final answer?? The answer is: they don't.

On my Commandos, I incrementally advance the Boyer until I get pre-ignition under high loads and high temperatures, then I back it off until it stops. You can do this without a timing light. This assumes you are running high octane gas, have good hearing, can recognize the sound of pre-ignition, can reproduce the conditions leading to pre-ignition, and are willing to put in the time to make a number of small adjustments. If not, get a timing light, confirm you are in the zone, and call it good.

Ps, you can buy good used timing lights cheap these days cause nobody needs them anymore.

Stephen Hill

I made my own piston stop from an old sparkplug. Hollowing out the core was at first hard, then once I watched a video on YouTube on how to do it by grinding/sawing off the lower metal flange, it was easy!
I used JB weld to pack around a length of old wheel spoke set into the plug body. Also passed a length of spray can plastic tube through the body...to allow air through when on compression stroke. Worked a charm.

Every bike I've fitted an ei needed the timing adjusted slightly when strobed. Boyers seemed to be always slightly advanced. Now I cheat the circle a little bit the other way. But still verify with strobe.

Stephen Hill said:

Supercat, as has been pointed out, the Boyer instructions tell how to rough adjust the timing so you can get the bike started, and a timing light will help you fine adjust the timing. For most folks, that is good enough.

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The trouble is the static Boyer setting is normally too advanced, plus the variation in the boxes components can vary the timing by several degrees. Strobing should be a priority after the first start. I replaced just the Boyer box, stator and rotor were untouched and the timing changed by 10 degrees retarded and the pipe went blue before the strobing was finished.

Wow! Thanks for all the help and info fellas!

Thank you Baz, yes, that would be the plan, but I've already got a printable degree disc that I downloaded from LAB's technical info section here on AccessNorton.

Thanks Stephen, and no I wouldn't expect the factory marks to give me a final answer, hence the piston stop, degree wheel and timing light. Your methodology sounds like it works well but I'm not sure I would be able to recognize pre-ignition and reproduce the conditions leading to it, as you mentioned. My plan is to print the degree wheel I mentioned, give it a solid backing, and use it with the piston stop to find TDC and 31 degrees BTDC. I can then then make my own marks and check things against what's happening inside the timing case following the Boyer instructions to make sure things are lining up as they should. When things appear to be satisfactory I'll attempt to fire her up and use the strobe light to get things spot on. The timing can't be too far off now considering how she was running last season.

I've still got a good bit to do before I'll be ready to try to start her up. I'm waiting on exhaust rubbers, and I need to change the fluids etc. So I'm trying to get the last few things I need all here around the same time so that I'm not held up.

Thanks Tornado, maybe I'll try to make one. I might spend some time on youtube checking into and try it out. And those are good tips htown16. And thanks kommando. It sounds like you are correct, and yeah it's now a priority for me. I want to treat her right.

I found the process of using the piston stop and wheel to verify my timing marks very satisfying. So the next thing I discovered was that if my timing chain wasn't adjusted properly, the results of the strobe where somewhat open to interpretation!

Good to know rvich - hopefully I won't have to mess with the timing chain, but I will if necessary. I'm sort of looking forward to this timing business actually. I've never used a strobe light before and I imagine I'll learn quite a bit. I haven't had the primary cover off yet either actually, but I know the transmission was working beautifully last fall.

Stephen Hill said:

On my Commandos, I incrementally advance the Boyer until I get pre-ignition under high loads and high temperatures, then I back it off until it stops.

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You mean detonation, not pre-ignition, don’t you?

If you loosen the primary cover, you are likely to find that you can shift the timing marks by a degree or two on the pins. For my marks to be accurate, I need to make sure the cover is rotated fully counter clockwise. It tends to settle clockwise because of weight towards the back. Keeping a record of what the timing marker says compared to what the degree wheel tells you will be a good thing.

If the timing chain is loose the mark tends to jump around when strobed, but then it kinda does that anyway, just to a lesser extent.

Thanks rvich. That's useful info. Your suggestion to keep a record of what the timing marker says compared to the degree wheel is a good one, and I'll follow that advice. Hopefully the chain is good and not loose.

One point to note....doing the timing on your own with a strobe is tricky. The fact the throttle & timing rotor are on other side of bike from the timing marks on the primary...means you need to have a helper running the strobe while you hold throttle at 3000+ rpm, then fiddle the rotor a bit and repeat. Also note, using the centerstand basically leads to the bike taking a walk across the floor as rpm's go up....so best to have both wheels on ground and someone straddling the bike or perhaps it's OK on sidestand?

Thanks Tornado - I'll get someone to help me out when the strobe light arrives.

In the meantime I just tried to unscrew the little cover over on the primary cover off to have a general look at the timing marks. The little cover is not moving. Is it ok to use an impact screwdriver on that? I've got a bit of penetrating oil on it for now.