Boyer Kickback

I am still having trouble with my kickstart. Sometimes it kicks back on my foot hard enough to break it. I have hard soldered and heat shrinked all wires to the Boyer including the harness under the tank. It has a brand new ignition switch. I am getting a good hard 12.48 volts to it and I have cleaned the ground wire. I hard bypassed the killswitch. I removed the push clips at the trigger and hard soldered them too. I am now afraid to attempt to kick it again as my foot has not recovered from the flogging it got this morning. I did check the timing when I first started it this morning and it was off a bit. I reset it at 32 degrees. then tried to start it and go for a test spin around the block. It kicked the crap out of me again. Sometimes it does it sometimes not?? If I do decide to check the timing marks with a degree wheel how do I make sure the motor is at TDC to do any necessary corrections to the existing marks. I am really geting frustrated. My foot is killing me and I may really damage something in my foot if this happens again. How critical is exact timing with a Boyer and could the boyer or triggers be faulty. I pulled the trigger plate off and inspected it well and it looks fine with no frays etc.?? Thanks for any further suggestions--Mark C.

Mark,

Use a piston stop to find TDC. This is usually an old spark plug with the porcelain knocked out and a length of bar stock welded in. Mount your degree wheel, put the bike in gear and turn the rear wheel until the piston contacts the stop. Record the degrees from the degree wheel. Turn the wheel in the opposite direction until it contacts the stop again. Record the degrees on your degree wheel. The distance exactly between these numbers is TDC. Remove the stop and turn the rear wheel forward until the pointer is 31 degrees before this number. Read the degrees where the alternator rotor mark aligns with the the degree plate in the primary cover. This is true 31 degrees BTDC. Record this number and use it to strobe the engine.

Once you are certain your timing marks are correct, then I would check to make certain the triggerwires from the box have not been crossed. If all this checks, then I'm afraid there is something wrong with the box or trigger.

Mark, The bike knows that your foot hurts and it knows that you're scared of it !

The implication is that the timing is too advanced. You could try retarding it a little to see if it helps.

Does the strobe do anything odd like move erratically as it comes off idle or does it go backwards sometimes ? It sounds daft but I have seen it happen, only to be told by Boyer that the unit was OK.

I have also had the situation of a newly supplied Boyer with a slightly over length rotor fixing bolt - Just long enough to bottom out before the taper held firmly but enough to pull it up a little. Each time it kicked back, the timing changed slightly. If there is a variable like that then it can take a long time to find.

I don't think that a couple of degrees is going to turn a docile starter into a monster. There is a definite problem somewhere. Can you borrow a spare unit somewhere to try substituting ?

I think I will check the magnetic rotor next too see if the mounting bolt bottomed out before it became truly tight. The timing stayed steady at 32 degrees without much fluctuation. I am using a Sunn inductor powered timing light. I was not the original installer of the boyer. I will completely check all connections again also. If the cam chain is not tight enough can it cause enough timing fluctuation to cause kickback?? I do have another boyer on a parts bike (not sure of it's working condition), and I will swap them out next. I am going to do the degree wheel thing this weekend first though just to make sure. Are there any newer electronic ignitions anyone can recommend in case mine has gone South for the winter??? I cannot risk another kickback or I won't be able to walk for a while. Thanks and I will post results or my hospital room if you want to come visit me---Mark Cigainero

Mark Cigainero said:

Are there any newer electronic ignitions anyone can recommend in case mine has gone South for the winter???

Click to expand...

We now have Pazon, Sparx and Tri-Spark types available although I cannot personally recommend any of these units -yet.
I have just ordered a couple of the new Tri-Spark units (one for my Commando, the other for my T160 Trident) and will report back on how the Commando one performs once I have fitted it. But my Boyer unit that is still fitted to my Commando certainly hasn't given any kick back problems at all.


http://www.pazon.com/

http://www.sparxelectrical.com/

http://www.trispark.com.au/index.htm

Could you say what procedure you use when kickstarting? As just kicking when the crank has come to rest in any random position won't help matters.

You have repeatedly mentioned setting the ignition to 32 degrees-why 32 degrees and not 31? Or maybe even try a little less advance?

If you're not seeing anything odd with the strobe then I don't think that there is a problem with the electronics of the Boyer. More probably a "peripheral" fault.

I've never seen a cam chain with enough slack to cause problems in the timing department and I think that you have to be a long way out at fully retarded to cause chronic kick-back.

The other old favourite with Boyers is for vibration to fracture the lead to the pick up. However, this occurs inside the intact insulation, usually where it passes through the crankcase. Once again, you have a dry, oxidised end contact which can cause what you describe on an intermittent basis.

I hear good things about the Pazon systems and the Lucas RITA is no longer available. I am now using my 25 year old Boyer (with new wires soldered on) but everytime I am tempted to fit one of my two newer "reserves", I end up with odd faults which Boyer say they cannot replicate so I think that my next step will be a Pazon (but then I'll have to buy two because I wouldn't want to tour without a spare in the tool kit !

79x100 said:

The other old favourite with Boyers is for vibration to fracture the lead to the pick up. However, this occurs inside the intact insulation, usually where it passes through the crankcase. Once again, you have a dry, oxidised end contact which can cause what you describe on an intermittent basis.

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I had a similar thing occur when one of the soldered wire joints on the pickup plate failed, as that can happen if the wires are not secured to the plate with small cable ties (had been removed by a PO I suspect?) and is another common failure point for Boyer equipped Commandos, rather more so than Boyers used for other makes of bike (probably due to the Commando engine shaking about on the Isolastics). I replaced all the pickup wiring and re-soldered the joints and cable tied them to the pickup plate and it has been OK ever since.

One reason for the pickup wires failing in the area of the crankcase is because they have been tied to the frame too low down, which can result in a rather sharp bend in the wiring, and the shaking of the engine then does the rest.
I like to tie the wires to the down tube far enough away to leave at least 6 inches of loose wire between the frame cable tie and the crankcase drill hole.

L.A.B. said:

One reason for the pickup wires failing in the area of the crankcase is because they have been tied to the frame too low down, which can result in a rather sharp bend in the wiring, and the shaking of the engine then does the rest.
I like to tie the wires to the down tube far enough away to leave at least 6 inches of loose wire between the frame cable tie and the crankcase drill hole.

Click to expand...

I'll second that. I actually use old fashioned rubber ties rather than the nylon type to allow a bit more freedom and a good loop of free cable. I now use black two-core mains cable for the pick up feed as I find that the bonding gives greater resistance to fatigue but I suspect that if one covers enough distance, it's a question of when rather than if.

The art with Commandos of course is "Anticipatory Preventative Maintenance"

One of you gents mentionioned the manner in which I may be kickstarting the engine. At what point in the compression stroke is it best to give it a good hard kick?? This seems wierd that you must get the engine at a certain point in the compression stroke to kick it???? Can the manner of kicking it produce kickback. I weigh 190 pounds and when I had an 850 in the seventies I cannott ever remember getting the terrible kickback I am getting now and I don't ever remember starting my kick downward motion at any particular point in the compression stroke. I would just give the kickstart slight pressure till I felt resistance and let it rip with no problems (severe kickback). I will replace the trigger wires al the way down the frame and through the engine.

Applying a low voltage to a boyer will cause it to over advance, so a battery on its way out will cause a kickback on starting as it will be at its lowest voltage, once the engine is running the voltage will climb and give good timing.

Test your battery as per RF Whatley's instructions

http://www.gabma.us/docs/batterytesting.pdf

Test to see if the boyer sees the battery voltage, if not test connections and the kill switch.

Accurately confirm the Norton timing marks are correct as they normally aren't

Mark Cigainero said:

One of you gents mentionioned the manner in which I may be kickstarting the engine. At what point in the compression stroke is it best to give it a good hard kick??

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Turning the crank to around the TDC position before kicking should give the crank the maximum momentum to overcome the next compression stroke. The Commando crank is quite heavy but still needs to be turned over fairly fast to achieve this, and a lazy prod on a Commando kickstart just doesn't work like it would on some other bikes, but from what you have said I think you are probably using the right technique if you are turning it to compression, I like to give the lever another 1-2" push, then allow the lever to fully return, press down until the ratchet engages then give it a good hard kick.

Or if I'm feeling lazy I use the electric starter instead!!

Mark Cigainero said:

This seems wierd that you must get the engine at a certain point in the compression stroke to kick it????

Click to expand...

I guess you have never been a BSA Gold Star or Velocette owner then Mark?

If changing the pickup wiring doesn't improve things and the battery voltage is now as good as you said previously, then maybe changing the ignition system could be the only option left?

Mark,
How does it start after static timing ie before you strobe it?
Cash

Many thanks to all of you who gave great advise. I pulled the triger wires this evening and cut them back to see if any were broken where they pass unnoticed theough the engine timing casing. All of it looked acceptable. I replaced them anyway. I proceeded to reground and hard wire everything in sight only to find no more obvious problems that should have effected Boyer voltage???I have a parts bike that had a Boyer on it so I replaced the module on the bike with it. I checked the continuity on the existing magnetic points transformers and they checked out just fine. The battery is also new and the voltage to the Boyer again still checked out. I even used an 1157 stop light bulb to test to make sure it was not just voltage but current as well. The light glowed brightly at the boyer power up connections?? After wiring in the dihferent module I checkd the spark and it was fine. I was afraid to kick the bike over so I got a push and it started fine. I then set the timing and it runs like a new bike. I am just afraid to use the kickstarter

Just keep your knee slightly bent, or get a "mate" to do it.

I can understand your fear of kickback. In my early days of Velocette Venom ownership I had a few such nasties until I learned the rigid and specific routine which had to be adhered to for that particular bike. Manual ignition advance, too.
On your Commando, run another strobe timing check between idle and up to about 1500 rpm. The timing should be well retarded at low (cranking) revs. If it seems to be in the 5 to 15 degrees btdc region then you are probably going to be ok to kickstart. Also try it when battery voltage is a bit lower (you can achieve this by having headlights etc on at time of test). If strobe timing is fairly steady and below 15 degrees all is well. If it scatters and jumps about exceeding 15 degrees I suspect a faulty control box, but judging from the logical tests and substitutions you have made I feel you have probably sorted the problem. It's just a matter of getting your confidence back to give it a hefty swing on the kickstarter.
I need to have my Commando on the centre stand to fire it up. It needs absolutely all of my 150 lb weight thrown with full commitment into the kickstarter, ensuring to follow through confidently with the swing right to bottom of travel. Any half-hearted attempt and the thing may bite back. I cannot get enough energy into the crank unless the bike is on it's stand. A bigger stronger bloke would probably manage it.

scim77 Kickback reply.

Thanks. That sounds like excellent advise. I will check the timing at lower revs and see how it all looks at around 1500rpm. If the timing jumps around I am going to tell my but ti scrap the ebtire system including the coils and go with a Pazon. It is my buddies 850 and he weighs about 145. I weigh 190 and I still have to place it on the stand to start it comfortably. I will also wear heavy supportive boots with lots of padding beneath!!!

I agree with SCIM77 don't try to kick it over with the leg muscles. When I first bought my machine I had a couple of nasty kick backs, My previous bike being a yamaha trail you could start with a hand push on the lever.
It needs top dead centre, then an all the body weight kick through to the bottom of the kick lever stroke. If it does kick back its because I pulled my weight off before finishing the stroke.
I have suffered a worn shaft and loose kick lever because of this method but its better than a broken foot. Just got to remember to tighten the kicklever every now and again.
Remember show it whose the boss!

hey mark, your buddy is really lucky to have a mate like you, sacraficing your body to sort out his bike! i remember when i first got my bike almost 2 years ago, the battery was on its way out, low voltage with a boyer, it sent me over the moon. i was limping around for quite a time. you have had great advice, kick that thing like you mean it. once in a while i will get complacent and not kick through and get a firm reminder. i have other problems at the moment, but my ankle is fine. enjoy the ride.......jerome