Sore Leg

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Feb 22, 2006
Lady & Gents, Does this sound like a float problem too, trying to kickstart the old girl has become a real ankle breaker, once it is started it runs nicely but trying to get to that point is impacting on my leg so much i now can't walk straight any more, it's kicking back in the carbie at all points of the kickstart, from the bottom of the stroke to the middle to the top, i have tried all different adjustments of the air pilot screw, i have had the carbie apart and checked every orrifice made sure the gasket isn't catching etc. I wouldn't think it was a timing problem or it wouldn't run as sweetly as it does, any ideas.
Are you still using points or have you switched to electronic ignition?

Recently a friend of mine encountered somewhat the same problem. A weak battery allowed the engine to fire the Boyer ignition just enough to leave him hobbling for days but not enough to get the bike started. The bike started right away after the swelling went down and a good battery was installed.
Thanks Ron,
Boyer ignition, i had thought of what you said , but my battery is only a month old!! :?:
Just a thought. I had a similar problem with a BSA, Harder and harder to start, but ran OK. Turned out to be a sticking exhaust valve on one cylinder when cold. Compression test confirmed. Don't remember there was much kickback.
be VERY careful until you solve it, man !!
i broke the tib/fib "plateau"- kickin' my old
shovelhead 3 yrs. ago. not good.

New battery may not be a good one take it in and get it load tested. You can prefom a crude one. Turn on bike don't start, run head light 3 minutes. The battery should still read above 12 volts. A carb can't make it kich back only a misplaced spark. Have you checked your kill switch circut real well?
Thanks Norbsa,
I'll do a load test on the battery, i thought about it and discarded it, being a new battery, but i have had a similar experience with a new battery just recently.
Regards Mike.
I'm going to be the one who asks the dumbest, freshest and most personal question of all.... :wink:

Are you kicking it "through"? If you go at it half hearted and wait for it to kick back, it will sense your lack of determination and give you one back just for good measure. I walked "the walk" for about two years, till I figured out that fear of kickback was the reason for all the pain. I just wasn't kicking it through the compression with enough power to keep it going forward, I was so busy waiting for it to hurt me that naturally it kicked me back, just for good measure..:D

Indeed the battery might be bad, but a weak battery won't cause the motor to fire at the wrong time, just cause it not to fire at all and the carbs have nothing to do with a kickback, as pointed out above. A sticking valve, would cause it to blow back through the carb, or out the pipes but unless the valve was sticking closed; a practical impossibility with out having a bunch of bent valve train; not cause much of a kickback at the kick start lever, as all the power would be going out the carb/pipe instead of against the piston.

It is either out of time, got a broken wire that makes contact at bad times, or now that it has done the kickback to you a few times, you have gotten over-cautious and you are not kicking with determination...

Recheck the wiring, reset the carbs for a good idle when you get it running, and think on whether the leg pain, is causing the kickback...that's what caused mine.. :D
Point taken Hewho, i have been a bit reticent on the downward stroke, but sometimes all you have to do is just put some weight on the kickstarter at the top of the downward stroke and it kicks. By the way where is deep in the woods of schnitzelland :?:
As Ron has already mentioned low battery voltage can cause the timing of the Boyer ignition to vary.

Although if the battery is new then it may be discharging for some other reason (faulty rectifier or Zener diode for instance?) or there could be a bad connection somewhere?

Have you tried disconnecting the battery when the bike is not in use?

Also just because the bike seems to be running OK doesn't mean the ignition timing is exactly right, have you checked it with a strobe (31 degrees @ 5000 RPM) as the Boyer rotor could have slipped as it is only held in position by being screwed down to the camshaft taper, there is no peg or slot to locate it?

I have a Boyer ignition fitted to my Commando and if the correct kick starting technique is used it does not kick back, in fact I don't think it has ever really kicked back noticeably?
Thanks for your input L.A.B., your correct a well sorted Norton shouldn't kick back and should start first or second kick as mine did up until recently, i put it on the charger overnight but i haven't yet tried to start it, if it is still a problem i will look at the timing, i read a thread the other day saying you could check the timing at about 3000 R.P.M. and 31 deg. is this correct. :?:
mike mcmanus said:
i read a thread the other day saying you could check the timing at about 3000 R.P.M. and 31 deg. is this correct. :?:

The Boyer instructions say 5000 RPM so in my view that is what should be done as the timing isn't fully advanced otherwise.
Iam not kidding on the kill switch a falty one can do this to you. When the boyer dosen't get it's volts the timming scatters and it throws random miltiple sparks. Just as a test direct wire the boyer by bypassing the kill switch in the head lite. You need to practice this till you can do it on the side of the road at night. It's well worth your time just to know how. Please do this after you know your batt will hold the head light for three min. and still have over 12 volts.
Sorry Norbsa, i didn't get the thread on the killswitch for some reason , could you send it again.
Regards Mike
The kill switch is another good place to use a relay. The relay will hold in with reduced current from the kill switch if it is a little corroded, but the primary circuit of the relay will always transmit full voltage to the Boyer. Plus you can mount the relay out of the weather!
kill button relay

Hi Ron,

The kill button is normally closed, when pushed it's open. A relay is normally open until powered, then closes. If you connect the kill circuit directly to the relay won't the relay be biased at rest creating a current drain? How do you get around that?
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