I've kicked and kicked and...

kicked, but I can't get my MKIII to even sound like it wants to try and start. I did a search here and didn't have any luck trying to find troubleshooting tips. One question, if I pull the plug and hold it against the head what kind of spark should I see? Are there other places I can check to make sure there is voltage, like the coils or? I'm such a newb with this Norton and the Haynes manual I bought is so worthlesss that I doubt it will even burn when I throw in the next campfire we have. I'm just looking for a list of things and places to check. I will start with spark at the plug and then check to see if there is gas on the plug. I have have a new ignition switch and new battery, what else can I check?

kustomizer said:

kicked, but I can't get my MKIII to even sound like it wants to try and start. I did a search here and didn't have any luck trying to find troubleshooting tips. One question, if I pull the plug and hold it against the head what kind of spark should I see?

Click to expand...

Yes, a spark.

What ignition do you have?

So so refreshing to flash back on identical manhood maturing forced by desire to ride a Commando. You even express similar regards to the manuals aid.
You need good spark at the right time, fuel mix to burn and compression for joy noise.
Electrics are the prime boogaboo on most bikes not just Nortons.
Mixture next in line, too much or not enough air or gas or leaks.
Compression loss is more serious and rare as white buffalo.
Of course more than one at once is common enough can never put out of mine.
Always keep some fresh plugs around - rare as they fail I've had new ones beat me down kicking for nothing till put old plugs back for 1 kick joy - sheeze.

Pull plugs and lay of clamp to head or ground to relieve kicking and to see-hear spark. Key on and jiggle wigger wires and pound on kill button headlamp to tail lens. If it pops there's first place to focus on.
There are plenty of Boyer ignition check lists, scan though here or google.

Same with carbs, if was good just prior likely not them but still could be.
Start with the lazy checks then if no joy face up to dig way deeper.
I've found most Commando will start 1st kick. I got so used to that if 1st didn't light her off I didn't waste effort on another till turned key on, put plug leads back, turn on gas, found coil connection broken, bad fuse ends loose, etc.
Solving relationship issues will a breeze or simply let to fester to an end to get attention back on better troubles.

hobot

Make sure the sump is empty (search "wet sump" if that doesn't resonate). That extra oil in the sump can be a biotch.

Then, check compression (unlikely to be such a problem as to prevent starting) make sure you've got spark on kickover (lay plug on head and kick over, look for spark between plug electrodes), THEN worry about carb.

There's a saying - 95% of carb problems are electrical. Generally true.

With Amals, make that 80%.

Best of luck.

You haven't said whether the bike has been running i.e. have you just bought it ? - a few things to check:-

1) Assuming you have Amal Mk1's when you press the ticklers does petrol pee out after a second or two ? - if yes then you can assume you have a good fuel flow.
2) Are the spark plugs really clean ? - if you lay the plugs on the head and kick you should see a good spark (not just hear a slight 'tick') - I've seen plugs that spark when out of the head but won't spark under compression due to carbon build-up inside the plug.
3) Check the ignition timing - the method depends somewhat on the type of ignition system fitted but in all cases you need to set it with it in the fully advanced position - with normal points you need to lock the auto advance in the fully advanced position with a washer and then set the points to just open at 29 degrees BTDC. With electronic systems you don't need to lock anything but the timing is roughly the same (Boyer is 31 BTDC, Tri-Spark is 29). For simply starting the timing is not too critical but it's wise to strobe it once you've cracked starting it.
4) It might be an idea to check the valve clearances - if any have closed up you may be loosing compression.
5) If the bike has been layed up for a long time with petrol in the carbs then the internal jets may be gummed-up (modern petrol is horrible stuff in this respect !). You may need to strip them down a clean all of the jets (compressed air is best - if you haven't got a compressor you can buy airosol cans of compressed air - I've found that the nozzle supplied with most of them are an ideal size for blowing out carb jets.)
6) You need to check all the ignition wiring - a common fault is where corrosion sets-in in the ignition kill switch - if this happens it completely isolates the ignition system. It's not unknown for ignition switches (i.e. the 'key' switch) to develop problems. Check that you have a decent 12 volts from the battery. If you can manage it it may be an idea to run a temporary link directly from the battery to the ignition system thus bypassing lots of potential problems.
7) The problem may lay with just one cylinder - Commandos normally start well on two working cylinders but can be temperamental to start on only one. You should get at least a 'pop' or 'bang' however.

Hope this helps - best of luck.

Keep us posted - - -

My Mk3 had green crud on the kill switch terminal and the whole kill switch internals were pretty sad. Bad connections after 30 + years of neglect.
Pull the wires and short them so you know it's not that. The manual should have a wiring diagram to follow. (I haven't seen a Haynes manual, but I assume it has a wiring diagram)
Does your electric start work? Will it start with that?
graeme

The only thing I'd add is when you pull the plugs, lay it them on the head and kick the bike (well, kick the start lever, not the bike itself, that comes later), you should see a healthy BLUE spark. If you see an orange or yellow spark, it will not reliably fire the mixture at all. From that point on, it becomes a wiring/voltage issue though a bad e-ignition module can do it as well. If you have a Boyer, be sure you have a good healthy battery, they are well known for poor starting and other characteristics when the batt voltage is much below 12.3 or thereabouts and that's even a bit shaky.

Fantastic info, thanks! I'm heading out of town for the weekend, but will hit this checklist on Monday and hopefully I can get this thing running. To answer a few quick question, yes there is fuel when I hit the ticklers, don't know what type of ignition, and the carbs were rebuilt when the bike was parked and haven't had fuel in them since. I'm leaning to some kind of electrical issue like the kill switch as I had to replace the ignition switch because everything was completely dead after the main power input to the switch. Thanks again for these places to start, they help a ton!

Dry carbs setting up can oxidize the zinc in the pot metal and crust up pilot jet that starts the bike. If found can boil in vinegar to leave clean to the nooks w/o need to probe passages, usually.

Safe Journey,
hobot

hobot said:

Dry carbs setting up can oxidize the zinc in the pot metal and crust up pilot jet that starts the bike. If found can boil in vinegar to leave clean to the nooks w/o need to probe passages, usually.

Safe Journey,
hobot

Click to expand...

Thanks hobot!

I learned that from a real m/c mechanic on Brit Iron list so looked up the chemistry to find the explaination while NO hydrocarbon solvent will touch this white crust which is identical to the white seen on coaches noses.

Stiff upper lip facing Commando unknowns, the carrot is it may deliver the best road orgasms and close intimate spooning you ever get short of having your back clawed, though that is possible too : (

hobot

Step one, ground a plug in dark garage and kick it over to see a spark, then same for other side.

If see two sparks then clean present plugs or put in new ones.

Then gas on, tickle till overflow and then ignition on and kick strongly while giving at same time one quarter throttle.

All while saying a short prayer to Joseph Lucas, your beloved WILL fire right up!

Well, I checked for spark at the plug and there was none. So I took apart the kill/starter switch and found a corroded mess as well as a broken wire. So I have a new switch coming tomorrow and will get that installed and see what other problems there may be or with any luck that was the only problem left and it will fire up! We'll see.

kustomizer said:

Well, I checked for spark at the plug and there was none. So I took apart the kill/starter switch and found a corroded mess as well as a broken wire. So I have a new switch coming tomorrow and will get that installed and see what other problems there may be or with any luck that was the only problem left and it will fire up! We'll see.

Click to expand...

Kill switch, huh?

<quietly goes back to whatever I was doing before...>

Well, still no spark at the plug. I replaced the switch and I have voltage at the points and on the positive side of the coil. Where else can I check?

Checked the HT leads from the coils to the plugs? This bike has breaker points right? With the igniiton on do you get a flicker of spark at the points if you flip them open and closed? You've got the ballast resistors up next to the coils? If those are connected OK, you should get a spark at the plug simply by flipping the points open and closed. If the points spark, then follow the leads up to the coil and ballast resistors. Check each connection, corrosion also gets into those.

If you have a multimeter, insert the red probe into a ground on the bike, i.e. jam it between the head and the headsteady bracket. Set the meter to <20Volts DC and use the black probe to check if you're getting battery current around 12 V DC into the respective points - resistors - coils connectors. The last item is the HT leads, simply continue to make sure the connecttion are good and fit a clean plug, lay it on the head and kick over to see if a blue spark arcs.

Mick

Engine needs a good ground to complete spark jump, got that checked off?
Test coil power by grounding test light on engine, if you ain't already.
Could be shorting right in the points area, double inspect check there.
Points ignition needs intact 'condensors'. I've had to dig old ones out of trash to get a spark new ones failed to deliver. About any will work as about all point systems use about the same size point contact to dampen reverbs of coil back feed.

Thanks ML and hobot, I'll check that out in the morning!