Boyer Questions (MKIII)

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Josh Cox

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Boyer Questions:

The Boyer suggests 28 BTDC, during normal operations, does the unit advance and retard the timing with the RPM ?, if so, why does it kick back like a bi'arch when you are trying to start it ?.

Using a cheap timing light whilst using the bikes battery, am having trouble getting a good flash rate, timing appears to jump around circa 5 degree, using same timing light indicates no advance or retard function.

With my BSA A10 and the K2F magneto and auto advance, the spark at idle goes in at around TDC, at high RPM 28-32 BTDC does the trick.

What is the best setting for the Norton with Boyer (BTDC) ?.
 
Set at 32deg. BTDC at 5000 revs.
Your A10 should be set at a distance BTDC fully advanced, unless you have worked out the degrees.
 
Josh Cox said:
Boyer Questions:

The Boyer suggests 28 BTDC, during normal operations, does the unit advance and retard the timing with the RPM ?, if so, why does it kick back like a bi'arch when you are trying to start it ?.

Using a cheap timing light whilst using the bikes battery, am having trouble getting a good flash rate, timing appears to jump arouns circa 5 degree, using same timing light indicates not advane or retard function.

With my BSA A10 and the K2F magneto and auto advance, the spark at idle goes in at around TDC, at high RPM 28-32 BTDC does the trick.

What is the best setting for the Norton with Boyer (BTDC) ?.
Click to expand...


Yes the Boyer does ( or should ) advance the timing with RPM. It should be 32 BTDC at 5000RPM as Flo stated. You need to use a separate battery for the strobe, it can cause some kind of interference if you use the bike's battery.

To set it up initially, put the engine at about 32 BTDC and turn the magnet disc (the reluctor) until the centre of one of the magnets is lined up in the hole in the stator plate marked "anti clockwise". The reluctor needs to be loose on the camshaft and the stator plate screws should be in the middle of their slots to give you some play either way for final adjustment with the strobe. Tighten the reluctor mounting bolt , and the stator screws, and this should be close enough for the bike to be started so you can use the stobe to get it spot on.
 
Josh Cox said:
The Boyer suggests 28 BTDC,
Click to expand...


Flo said:
Set at 32deg. BTDC at 5000 revs.
Click to expand...


pommie john said:
It should be 32 BTDC at 5000RPM as Flo stated.
Click to expand...



It's 31 degrees-according to Boyer Bransden.

http://www.boyerbransden.com/pdf/KIT000 ... 00017_.pdf

Start engine and time with a stroboscope to 31 B.T.D.C. (28 DEC. with standard ignition) with the engine
running up to 5000 r.p.m.
Click to expand...



Josh Cox said:
why does it kick back like a bi'arch when you are trying to start it ?.
Click to expand...


That is usually a result of insufficient voltage (B-B Micro MkIII ignition).
 
Have the timing set nicely, having a little trouble with the spark on start.

Have two brand new 6 volt coils, Boyer set up correctly.

When the spark plug fires, it is a really nice blue spark, when kicking over on centre stand, does not appear to be a spark every compression stroke. Will confirm this with an oscilloscope in the next few days.

Is it common for older boyer magnets on the cam to lose magnetism, giving not so good indications to the unit ?.

All wiring and earths are good, power is a solid 12 volts from a new 11 AH AGM sealed unit battery.
 
Got the oscilloscope on the job today, the Boyer is working fine, even for starting.

Problem appears to be running too rich at idle and carboning up the plugs , when my Vacuum Gauges arrive I will set the idle mixture where it should be.

As soon as my wheels are finished I think there will be a trip to the Dyno.
 
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