kickstart kicking back!

coomo

coomo

Joined
Oct 10, 2018
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Guys.My 71 750 had a slipping clutch.It was a Barnet,so a good quality unit.However, it began to slip under fast acceleration.yes I did have the oil seal mod.It was always easy to kickover & start.I realise that starting issues arent going to be related to clutch issues.However recently when I kick it over, on occasions it kicks back hard.Real hard.The only recent variable that has changed is that my engine guy
fitted a new set of clutch plates.he used bronze sintered variety.I dont have any slipping issues anymore, just the dread that im going to break an ankle kicking it over, when previously I could start it
with soft soled shoes on.Does anyone have any opinions as to wether this could be due to the Bronze clutch plates?
 
OK, check boyer stator plate under the "points" cover to see if the fixing pillar bolts have come lose. Also the timing rotor beneath the stator plate might have slipped on the camshaft. Check the timing marks on rotor & primary cover timing scalewith left side piston on compression stroke (remove spark plug and rotate engine until you feel pressure with thumb over plug hole). Check the boyer plate marks/holes or whatever it uses to line up with the rotor magnets (instruction book or pdf on-line will have this). When engine turned with those aligned, the timing mark on the crank rotor in primary should line up around 28-31 degrees on the scale.
 
Coomo,
What boyer type do you have? Boyer Mk111 ?
Check your battery voltage if you have this earlier boyer. The types mentioned always want 12 volts. They get erratic under 11 volts. So if your battery is on its last leg or lost a cell that causes kickback. Shoddy wiring can also cause problems. i.e. bad connections. The Commando E start bikes cursed the Mk111 type boyer's as they would damage their starter parts in the primary when the voltage got too low. Not the fault of the Boyer mk3s, its just that these need to be fed on 12 volts all day and it will behave on its timing curve. Anything under and it gets erratic.
The boyer Mk4 corrected that low voltage issue. They are still stable below 12 volts by a safer margin.
Pazon Surefire corrected this problem long before boyer got off their duff and started marketing the mk4s so that's something to check.
Cheers,
Tom
 
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Correct Spark timing is a thing that is based on your bike's Air/fuel mixture ratio... If your timing rotor somehow loosens and moves that could cause a wicked kick back.... But if it doesn't move and your bike's idle circuit becomes clogged so your A/F ratio is now a very weak fuel mixture, your bike will kick back because the weak mixture burns much faster.... so your spark is now far advanced for such a weak mixture. If this later scenario is the case in your situation then you unclog the idle circuits, and your bike should return to normal. (assuming that your boyer magnetic rotor had not moved, of course)

I've run a boyer of one kind or another on my commando for 40 years and never had the rotor slip. I have poked the idle air screw jets about a dozen times and one year I even removed the carbs and drilled out the back side of the carburetor so I could clean out the passage behind the idle jet. (then I tapped the hole and installed a set screw in sealant to reseal the passage)

I would bet your idle circuit/s have some shit in it/them, but as usual you need to check timing and fuel delivery since they could both cause the symptom
 
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o0norton0o said:
Correct Spark timing is a thing that is based on your bike's Air/fuel mixture ratio... If your timing rotor somehow loosens and moves that could cause a wicked kick back.... But if it doesn't move and your bike's idle circuit becomes clogged so your A/F ratio is now a very weak fuel mixture, your bike will kick back because the weak mixture burns much faster.... so your spark is now far advanced for such a weak mixture. If this later scenario is the case in your situation then you unclog the idle circuits, and your bike should return to normal. (assuming that your boyer magnetic rotor had not moved, of course)

I've run a boyer of one kind or another on my commando for 40 years and never had the rotor slip. I have poked the idle air screw jets about a dozen times and one year I even removed the carbs and drilled out the back side of the carburetor so I could clean out the passage behind the idle jet. (then I tapped the hole and installed a set screw in sealant to reseal the passage)

I would bet your idle circuit/s have some shit in it/them, but as usual you need to check timing and fuel delivery since they could both cause the symptom
Click to expand...
Well articulated.
 
CanukNortonNut said:
Coomo,
What boyer type do you have? Boyer Mk111 ?
Check your battery voltage if you have this earlier boyer. The types mentioned always want 12 volts. They get erratic under 11 volts. So if your battery is on its last leg or lost a cell that causes kickback. Shoddy wiring can also cause problems. i.e. bad connections. The Commando E start bikes cursed the Mk111 type boyer's as they would damage their starter parts in the primary when the voltage got too low. Not the fault of the Boyer mk3s, its just that these need to be fed on 12 volts all day and it will behave on its timing curve. Anything under and it gets erratic.
The boyer Mk4 corrected that low voltage issue. They are still stable below 12 volts by a safer margin.
Pazon Surefire corrected this problem long before boyer got off their duff and started marketing the mk4s so that's something to check.
Cheers,
Tom
Click to expand...
It will be a mk3 its only about 2 years old.I burned through 3 pazons in 3 years.(then switched to Boyer)My electrical guy couldnt figure it out, as all the circuit paremeters were fine.He noticed I had a race(solid) head steady.We changed it out.Has been all good since then.he reckons the extra vibration may have been knocking out the coils on the stator plate.Or maybe not.However,its been all good since.
 
coomo said:
It will be a mk3 its only about 2 years old.I burned through 3 pazons in 3 years.(then switched to Boyer)My electrical guy couldnt figure it out, as all the circuit paremeters were fine.He noticed I had a race(solid) head steady.We changed it out.Has been all good since then.he reckons the extra vibration may have been knocking out the coils on the stator plate.Or maybe not.However,its been all good since.
Click to expand...
Could you expand on your "solid head mount" please?
 
yea.It was a race head steady.Devoid of isolastic mountings.Cant recall much else, apart from it was made by a "Dave" someone!
 
My 850 is hard mounted in the Featherbed frame and I never had any problems with my old Boyar from vibrations or any of my electricals in the 44+ years I built it, well once when I first built it I lost one coil bottom when I had them mounted under my tool tray without rubber mountings, cut right off lol.
 
Boyer wires can fracture at the base plate if left unsupported , by using a small foam piece to prevent it and absorb vibrations . Mine did after many kilometers . Easily fixed . Or prevented .
 
coomo said:
It will be a mk3 its only about 2 years old.I burned through 3 pazons in 3 years.(then switched to Boyer)My electrical guy couldnt figure it out, as all the circuit paremeters were fine.He noticed I had a race(solid) head steady.We changed it out.Has been all good since then.he reckons the extra vibration may have been knocking out the coils on the stator plate.Or maybe not.However,its been all good since.
Click to expand...
Interesting. I have had a Dave Taylor head steady and Pazon ignition for around 7 years . (using the original style 6 voltage coils in series)

No issues except when I foolishly shorted the zener feed to earth and destroyed the black box. Blew the fuse but still destroyed the black box module.
 

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