MKIII blowback when kickstarting

Hi guys,

As I've been working through the many kinks of a freshly running rebuild I've come across a few things I was hoping to get some advice on. First and foremost, every once in a while when I'm kickstarting, the engine almost starts and throws the kickstart lever back to upright position with some force (certainly more force than just the spring). Its only done this 2 or 3 times out of many. Having never owned or ridden a properly running Commando I can't say as to whether or not this is normal, but without knowing one way or the other it feels a little scary since my foot is along for the ride. Any ideas what may be going on here? Happy to answer any questions.

Thanks,
Anthony

Happened to me once, on a kick that lacked full commitment! If that's not it, may be ignition timing, too advanced?

What ignition, Boyer MK3 will over advance with low voltage eg after the bike has been sitting for a few days on the first kicks until the battery is recharged.

kommando said:

What ignition, Boyer MK3 will over advance with low voltage eg after the bike has been sitting for a few days on the first kicks until the battery is recharged.

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Yes. It can really bite.

Anvill said:

First and foremost, every once in a while when I'm kickstarting, the engine almost starts and throws the kickstart lever back to upright position with some force (certainly more force than just the spring).

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Even when the ignition is fully retarded the spark still occurs a few degrees before TDC. If there's insufficient energy in the crank to carry it through TDC that can result in a kickback. If the ignition timing is over advanced or the AAU cam doesn't fully retard then it can make the situation worse.

I have a trispark ignition installed. But thanks guys this info helps.

Anthony

Mart UK said:

Happened to me once, on a kick that lacked full commitment! If that's not it, may be ignition timing, too advanced?

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OP, kicking technique is HUGELY IMPORTANT on these bikes. Much has been written.

Anvill said:

I have a trispark ignition installed.

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The Trispark has an anti backfire curve at kickover speeds, so if its kicking back then you are either just not kicking hard enough or the timing is advanced.

Have you verified your full advance timing with a timing light? Sounds like it is too advanced. Should be 29 degrees at 3500 rpm.

I did set the timing with a timing light but I will double check it. It’s also certainly possible I may have been a little soft on those kicks, my leg was pretty tired by the end of the day . I’ll do some reading up on proper kicking technique. Anyhow I’m glad to know that nothing’s damaged.

Anthony

Seeing you haven't any experience in owning a Norton before then just kicking it will not help you and you will suffer the pain of kick back if not done right, you got to learn the knack of kicking a Norton to life without that knack you will suffer, you have to get the pistons up TDC and just a little over and give it one big swing on the kicker, this is very important for the first kick of the day when the motor is cold and if things are set right should only be a one or 2 kicks to start but only if you do it right, if you try to kick it with the pistons down off compression then no chance at all, most ignition systems need the crank to spin a bit to fire, don't try to kick it like old Japanese bikes that had KS or a old Triumphs, they are easy to kick than a Norton, being a new owner it will take time to master the kick knack, but once mastered you will understand better in kicking a Norton to life and once they been started for the day it will be a lot easier to kick start them, its the first kick of the day that is the hardest, also wear decent boots, soft shoes are no good and a strong leg.
Being a M111 then it should have a electric starter but the original starters weren't the best without upgrades, they were more a kick start helper but with upgrades they were a lot better.
I have owned my Norton for 46 years now and I do have the knack first kick every time but when I bought it new and only 17 years old and skinny as a rake it did take me about a month to get it right and a good mate showing me the right way from the wrong, you don't have to be a big or strong person to kick them to life you just got to learn the right way of kicking them, its all in how you kick them and we all learn from our mistakes, usually the hard way.
Good luck with your training and learning to kick your Norton the right way.

Ashley

Here's something I tell people that often helps. You have to "think" the kick starter to the bottom of its travel. Unless you're tiny and weak, there's no need to jump and it's bad to do so. Ideally, as other have said/implied push down slowly until you feel great resistance then a little more. Then think about your favorite sport and follow-through all the way to the bottom. The engine has to have enough momentum to come around to a firing stroke and as it fires continue past top center to the power stroke.

Another mistake people make is cracking the throttle while kicking. You want the engine over rich - that's what the ticklers do. If you open the throttle, you make it lean and they are very hard to start lean!

You can usually slowly kick most motors over the top of their stroke against compression. If you do that with the choke on, before you really try to fire the motor up, the cylinder will have a gut-full of mixture and will become easier to start. When what you are kicking against is mostly air, you get a lot of resistance. When I kick-start a motor, I usually start with the piston a fair way up the cylinder. Usually a flick past TDC is enough to get the motor to start. Never jump on the kick-start lever madly because you will probably get bitten - do it slow.

And keep your knee slightly bent. If you lock your knee and the bike kicks back something might break.

I recommissioned a Yamaha XS750 years ago, and the starter sprag was a bit iffy and often it wouldn’t start, just whirr around. No new parts were available so I used the kickstart. I was there one day, kick, kick, kick, kick, kick when all of a sudden it started as I was barely half way down the kick. As a result all of my weight went onto my knee and I collapsed in agony. It took 5 minutes for me to recover from the pain and I limped for several days afterwards.

Anyway, almost a year later it was the same, kick, kick, kick etc and the same thing happened. This time the pain was excruciating and I didn’t recover from it

A trip to hospital and a scan and apparently my knee had over-extended and as a result my cartilage got chewed up. I then had keyhole surgery to remove and tidy up the cartilage inside. Pain over.

I advertised the bike on eBay and while demonstrating the poor starting of it, firstly the starter motor refused to fail like I’d told the buyer. It also idled from cold without fail, also I’d said it was a pain. The buyer was very happy and paid me.

I‘m certain the bike simply didn’t like me and wanted to get away.

Usually when you kick-start a bike you are wearing boots or shoes with heel, If you keep the kickstart firmly in the step in front of the heel, you can usually hold any kick-back which occurs. I got caught once . I had fallen off one of my brother's creations in our front street. It was a 200cc minibike which stood up and chopped out from underneath me at about 30 MPH. I was wearing no helmet and I had moccasins on my feet. I slid up the road on my side keeping my head off the road, but my toe caught and twisted my lower leg. It was painful, but I did not think I had broken anything. Some time later I was at home and a mate came around with a T120 Bonneville. I tried to kick-start it and it kicked back, but I caught it. What I did not know, was there was a flake of bone loose inside my knee joint and joined to my cartledges. I ended up on the ground - had a knee operation - then learned to walk again.

Maybe there's something in keeping the mk3 e-start functioning.

I have still not managed a kickstart from stone cold. Once ridden, it's fine, but it wouldn't get ridden without the e-start 1st thing. Also, I don't get the "kickstart assist". Do you kick it and press the starter? Sounds dangerous!

Mart UK said:

Maybe there's something in keeping the mk3 e-start functioning.

I have still not managed a kickstart from stone cold. Once ridden, it's fine, but it wouldn't get ridden without the e-start 1st thing. Also, I don't get the "kickstart assist". Do you kick it and press the starter? Sounds dangerous!

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I agree - no real excuse any more for a Mk 3 with a non-functioning e-start. Between the Dyno Dave starter motor / starter cables, CNW's improved sprag clutch, and a tuning of the anti-backfire device (all relatively simple fits/adjustments), you should have a fully functional starter for under a grand US.

I have a friend with a Mk III and all he did to make the starter work consistently was to replace the OEM starter cables with those of larger gauge. He made no other changes to the system, motor, etc. It still works fine - starts the bike with no trouble though admittedly it doesn't spin the engine over like an Alton or (I assume) a CNW.

I definitely agree with the concept that having a MkIII means you e-start the bike! Heck, I removed the kick start lever from my '73 about 6 months after I installed the Alton...10 years ago.

Have you checked for wet sumping and drained your crankcases? this can have a big effect on kickstarting. Also note that timing marks can be a long way out so have to be verified by measurement in the first instance and moved if incorrect.
It`s definitely worth getting the E start operational, I have met people with surgical scares from kickback! It`s not worth the pain when it can be started on a button. My MkIII is all standard apart from the upgraded earth cable and always starts eventually. Like Mike, I removed the KS after fitting the Alton to my MkII.
Best wishes, Al.