Kickstarting

Joined
Jun 14, 2007
Messages
1,732
Country flag
My 73 Commando 850 doesn't "kick through" each time. Seems to allow it about one time out of three. The other two times, the kickstarter can't be depressed - it sort of runs into a full stop. This isn't just compression, it's like it's hitting something. I've gotten fairly good at "feeling" which times are which, but every once in while I'll misjudge and do a flying leap up and back down onto a kickstarter that goes nowhere.

So the drill is sort of push it down a little, then again, then the third time kick it through.

Is this normal?

Thanks folks - BrianK
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,745
Country flag
That sounds like fairly normal 850 compression behaviour to me. My own 850 is the same.

The fact that it feels as if it is locking up is probably due to the centres of the main bearings, big ends, and gudgeon/wrist pins all being in a fairly straight lineat that point, and around TDC the crankshaft isn't able to impart much force to the rod and piston, so the whole thing seems to go solid, and if constant pressure on the kick starter gets it moving then I don't think there is a problem.
 
Joined
Jun 14, 2007
Messages
1,732
Country flag
To be clear, constant pressure will NOT get it started. Rather, when it's "blocked," I have to let off the kickstarter, let it rise an inch or so, try again, usually same result, and then the third time I can feel it will go and it does. It may be compression, but it doesn't feel like it - not "hard but compressible," but rather "locked" feeling???
 
Joined
Apr 7, 2004
Messages
1,691
You have to use your clutch to gain a new place for the petal. This lock up happens when the owner doesn't find TDC and than use the clutch to get the petal to a position that allows one to just stand on the petal straight down. A slow kick through with the key on to find TDC also avoids Boyer kick back .
 
Joined
May 7, 2005
Messages
5,945
Country flag
With the key on as the boyer fires you get a tiny kickback through the kickstart from unburnt fuel, you are now at nearly TDC.
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
17,745
Country flag
BrianK said:
To be clear, constant pressure will NOT get it started.

I didn't mean to imply that constant pressure would start it, only that the compression will leak away so that the pedal begins to move the crank.

BrianK said:
Rather, when it's "blocked," I have to let off the kickstarter, let it rise an inch or so, try again, usually same result, and then the third time I can feel it will go and it does. It may be compression, but it doesn't feel like it - not "hard but compressible," but rather "locked" feeling???

I agree Brian, it does feel as if something is locking solid, my own 850 exhibits the same characteristics.
But each time you release the kickstarter and retry it, the compression in the cylinder is slowly leaking away so eventually it will start turning the crank again.
 
Joined
Apr 7, 2004
Messages
1,691
Hi Debby, Boyer's fire both plugs each BTDC ... ever wonder how it deals with having a difficult job firing the plug on the combustion stroke. Why doesn't the power from the coil just jump to the easy plug like electricity and water like to do. The answer is that it uses the resistance to fire to teach itself how to direct the amps to the plug needing it. Now I am no E.E. I don't know how it works I just know it works through observation.
Boyer's need good clean power with grounds that tie the engine,coils.and brain box and battery ground to a common place. Assuming all is well with the sending wires your good to go. But even with all that done, if you walk up to your bike turn on the gas and key and just kick it, one can get kick back, just ask someone with electric start that uses a Boyer or anyone with a habit of just getting on and kicking . If these same folks just took the time to slowly push through the petal with the key on they would never get the dreaded kick back. Using the clutch while your doing this to get just the right place to start the kick should become your habit. When I see people kicking as opposed to pushing their engines through and not using the clutch to get just the right start I see someone who lacks knowledge of how it all works. And Boyer's are just made to kick the unknowables once in a while.
 
Top