Ignition Timing Setup Boyer

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As I have found out this is a greatly discussed topic from which I have gleaned information, but I am stuck getting my 73 850 to run with my knowledge of it being correctly timed.
I spent the good part of Saturday fiddling with a strobescope with hopeless results.
On Sunday I made the second move, I found TDC and with a timing disk on the crank reversed the crank to 31 degrees BTDC (see pictures) and set my Boyer with the magnet showing through the hole. Then I put the primary casing on to find the mark it was showing at 29 degrees. I have heard of loose casings but mine sits nice and tight.
Previously I had been doing all settings on the left cylinder and taking strobe readings from the left HT lead. Measurement checks were carried out on both cylinders with a stop gauge.
 
Ignition Timing Setup Boyer

Ignition Timing Setup Boyer

Ignition Timing Setup Boyer

Ignition Timing Setup Boyer
 
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Sometimes the outer part of the rotor comes loose on the inner hub part. Pull the stator off and see if there is any movement in the outer part of the rotor.
 
Mmmm, I had read about that too but I will check it is going to be a process of elimination. I have heard of the soap bubble meathod to find TDC, I would like to try that using the TDC plunger tool minus the plunger but how does one go about preparing the surface.
 
A positive stop is the best way to check, I assume

Measurement checks were carried out on both cylinders with a stop gauge.

is the same ie you stop the piston either side of TDC against a fixed rod down the plug hole and adjust the degree wheel so it reads the same degrees either side of TDC when it touches the stop.

Setting the Boyer rotor magnet under the right hole for the direction of turn is not a guarantee it will actually strobe at 31 degrees first time, it's just a guide and further adjustment will be required. If the alternator rotor checks out with no movement then 29 is your target as that is actually 31 as confirmed by your full degree wheel. Its not unknown for the timing case degree indicator scale to be out by a few degrees, either compensate based on your findings or drill out the rivets and move the degree scale so 31 actually points to 31 or make a new mark on the alternator rotor.
 
The piston stop/degree wheel is the most accurate way to find TDC. The bubble method, or ANY method that determines TDC by simply showing the highest point reached by the piston is inaccurate for precision use because it does not account for the fact that the crankshaft can turn slightly with no corresponding vertical movement of the piston when the piston is at TDC. So don't bother with trying some additional method of finding TDC, you did it the best (most accurate) way! :)
 
Do you think that would have been enough for ca. 2 degrees on my terrible scala on the primary.
Any idea why Norton did this, they are difficult to read as it is.
 
Well,... The timing disc only does one thing. It tells you if the position of your pistons and the position of the mark on your rotor are aligned properly or not... IF the rotor alignment is correct then and also matches the position of the degree scale on your primary cover, then forget about the Piston position/degree wheel baloney.... Once you verify it's accuracy, it isn't going to change... and you are DONE with that.


Did you just rebuild the entire bike or did you just add a boyer ignition to bike that previously ran on points? ( or ran on a different IE?)

The only other thing you need to know IF it's a complete rebuild, (not just adding a boyer to a previously running bike) is if the cam sprocket is positioned correctly in relationship to the crank sprocket, so the valves open and close at the right time. AGAIN, if the bike was not completely rebuilt and ran previously, then it should not be an issue now...

You really haven't provided enough information for anyone to help you. Instead, you are getting a debate about the best way to find TDC, which isn't going to help you position your boyer's magnetic rotor, nor adjust the pick up plate...

So,... Complete new build? or just adding a boyer system to a bike that ran previously??
 
Ok, I only had the timing cover off to set the camchain and installed a new spare Boyer transistor plate instead of the old one. The bike ran fine before and with this setting I now have after the latest operations the bike also ran fine starting first kick. It is just that these marginal inaccuracies bother me with regards to the running of the bike.
I have tried marking the rotor to get a better reading but it is still pretty miserable and could do with a tip as paint didn't work well for me. I do have a good list which I found on the website and so started trying with 3000 RPM to which ideally 22.8 degrees (23) could be a start.
To advance the ignition the plate should be turned clockwise, right?
 
Never seen a scale printed as bad though,

Unless I'm mistaken the photo was taken with the engine revving and the strobe flashing, possibly with the camera flash adding another light source which might account for the double image.
Edit: Or vibration?
 
The piston stop/degree wheel is the most accurate way to find TDC. The bubble method, or ANY method that determines TDC by simply showing the highest point reached by the piston is inaccurate for precision use because it does not account for the fact that the crankshaft can turn slightly with no corresponding vertical movement of the piston when the piston is at TDC. So don't bother with trying some additional method of finding TDC, you did it the best (most accurate) way! :)

' it does not account for the fact that the crankshaft can turn slightly with no corresponding vertical movement' - If you actually try the soap bubble method, you can assess the error in it by rotating the crank slightly backwards and forwards and watching the bubble. It is very accurate. A very small movement of the crank gives a big change in the bubble. You will easily find TDC to within half a degree. With the positive stop method, you need to divide the distance from stop to stop in half, after turning the crank almost a full rev. That is OK, if you already know approximately where TDC is, and move the disc so the zero is near TDC before you start. With the soap bubble method, you simply put the cylinder on the power stroke, look down the plug hole and move the piston to near TDC, screw in the broken plug and wipe your bubble on, and waggle the crank. You find TDC without doing maths.
 
Ok, I only had the timing cover off to set the camchain and installed a new spare Boyer transistor plate instead of the old one. The bike ran fine before and with this setting I now have after the latest operations the bike also ran fine starting first kick. It is just that these marginal inaccuracies bother me with regards to the running of the bike.
I have tried marking the rotor to get a better reading but it is still pretty miserable and could do with a tip as paint didn't work well for me. I do have a good list which I found on the website and so started trying with 3000 RPM to which ideally 22.8 degrees (23) could be a start.
To advance the ignition the plate should be turned clockwise, right?

I think the rotor of the Boyer turns backwards, so rotating the stator clockwise should advance the ignition.
 
My timing scale was off almost 4 degrees from what a positive stop showed. I simply noted what the difference is, and set my timing that many degrees off. It would probably be best to pull the rotor off and mark it with a sharp chisel, but that requires wa-a-a-y too much work. Maybe if it ever needs attention to the clutch...
 
You probably need to think about what the errors mean. If the error is advance, it often has the same effect as leaning-off the jetting. Best practice might be to set the timing then check that the carbs are jetted right for that setting.
 
Unless I'm mistaken the photo was taken with the engine revving and the strobe flashing, possibly with the camera flash adding another light source which might account for the double image.
Edit: Or vibration?

There was another very similar one posted recently and that was a misprint but the lighting on this one does look like under a strobe. With wasted spark and the required slack in the cam chain maybe this is what you get all the time and why crank triggered timing is better.
 
The piston stop/degree wheel is the most accurate way to find TDC. The bubble method, or ANY method that determines TDC by simply showing the highest point reached by the piston is inaccurate for precision use because it does not account for the fact that the crankshaft can turn slightly with no corresponding vertical movement of the piston when the piston is at TDC. So don't bother with trying some additional method of finding TDC, you did it the best (most accurate) way! :)

If there is enough slop in a crank to make TDC an issue when a piston is at TDC, then you need a new crank and bearings.
 
There was another very similar one posted recently and that was a misprint but the lighting on this one does look like under a strobe.

It's the same one, also posted by Woody850.

Once again it looks like the photo was taken whilst strobing and what perhaps we are seeing is a double image of the scale?

https://www.accessnorton.com/NortonCommando/timing-marks.27801/

Woody850, were the photos taken whilst the strobe was operating or is it a double print on the scale?
 
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Unless I'm mistaken the photo was taken with the engine revving and the strobe flashing, possibly with the camera flash adding another light source which might account for the double image.
Edit: Or vibration?

I think the latter. The SS clone tries to leap off the c-stand when strobing the ignition.

If you set up the Boyer according to the directions, the engine should fire and then you can strobe it to a final setting. Pretty much takes a person on each side of the machine.
 
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