Why won't it start (2008)

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RONED

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Mar 14, 2008
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Hi Gents,
1970 commando, last road 3 months ago, started and ran sweet as a nut, due to work it was left standing for 3 months, the battery was on a trickle charger, so that's OK, I have cleaned and re jetted the carbs, there is a good spark, but no way will it start, anyone got any ideas, it is a notorious wet sumper but that shouldn't effect starting, should it,.
 
Yes, "wet sumping" WILL affect starting.

The crank will spin in an oil bath as easily as you can walk through a swimming pool. Well, maybe not QUITE as easily, as oil is decidedly thicker than water.
 
Seperate story but related....My '75 came back from "the Norton shop" after a rebore to 20 tau. Started first kick. Had 2 quick rides on it (about 25 miles) and then it wouldn't start anymore either. Spark plugs are wet but gives spark, so both conditions are met for firing. However, I kickstart and kickstart till my tongue hangs on the ground but nuttin. Sometimes a "poof" and that is it. Keep trying about every 2nd day, but same. In despair I ordered a new electric starter from the boys in Colorado which didn't arrive yet. But I have that sinking feeling that installing a electric starter (the old starter was removed many moons ago by previous owner) will only give additional problems... What can be done/checked so I can have a starting Norton??? (electronic ignition)

desperate in Calgary
 
Have you done a compression check at all? That would be the first thing i would do. Then verify your battery voltage.
 
yes, compression check is done (better be with brand new pistons and rings) and battery is charged to the rim (and new)
 
Dump the engine case oil, put in new spark plugs. New gas not two week old gas. Load test the battery, only check the volts left in it after the head light been on and stays on for this test run time, two minutes. If you don't have 12.5 it's toast.
 
Battery shows 12v with headlight on, is that OK, I had put new plugs, so there OK, I,ll drain the sump put new petrol in, and hit the road, HOPEFULLY
 
To start, there have to be a few things happening at the correct time and under correct conditions.

Make sure the spark timing is correct, the rotor could have slipped (unlikely, but it is worth checking).

Make sure gas is flowing to the carbs, if you have Amal concentrics, flood them and close the choke. MK2 Amals have an enrichning lever like the Mikinis.

As mentionned, empty the crankcase of oil, the drag will prevent the crank from swinging freely and unless your engine is in perfect tune, there is no way it will start easily.

Even if the spark looks good, measure the voltage going to the coils, less than 12 volts means a loss somewhere. A spark in free air takes a lot less voltage than a spark under compression.

Faulty sparkplugs, if they are full of soot due to a too rich mixture, they will not make a good spark.

A weak kick will not do, put some oomph in it, go to McDonald's and pig out on Big Macs and fries (supersized of course), in a month you could have gained enough weight to start it ;-)

Jean
 
Another tip;
If the old beggar just wont fire up when usually it will. Switch the ignition off take the cold start off, and don't tickle the carbs. With the throttles fully open kick it over three or four times. Switch the ignition back on leave the choke off etc and try again with say 1/4 throttle. It might fire up and run normally but usually it'll rev up and stop, if so try and catch it with the choke.
Basically you're just drying it out.

Works for me.

Cash
 
Hi RONED,

Yet another tip, I find if I don't use mine for a while I can get it to go 1st or 2nd kick by removing plugs & squirting down small amount of petrol down plug holes.
I still use the choke (Amal MK2 carb) & find this successful everytime.
I also have a tap fitted on the oil feed which I turn off if parked for any length of time which eliminates wet sumping.
Give it a try & Iam sure it will work.
Regards Hursty.
 
I have to admit that I haven't used the Commando this winter (I've never known one like it for the amount of salt that they've put down).

I drained the oil at the weekend, put the fuse back in (the battery hasn't been charged though), turned on the old fuel, tickled it and swung on the starter. . . It started first kick and ticked over from cold. What am I doing wrong please ? :shock:

Dry electrical contacts and low volts at the ignition are probably favourite suspects if there's a problem.
 
Hursty,

I'm curious about the details of the tap you installed on the oil line. Is it a ball valve? How do you remember to open it before starting the engine?

Jason
 
I have one of those quarter-turn ball valves on my '75 T160 Trident; I have nightmares that I'll forget to turn it on one of these days...
 
Hi Jason,
Yes it is a ball valve I have adapted in the oil feed.
When in use it is locked in the open position by a tie wrap.
I leave it on for up to a week & if I am not using the bike for more than that cut the tie wrap and turn it off.
I usually wrap a piece of white tape to the kickstart rubber as my reminder that oil supply off.
I find its much better than letting a bike wet sump & I use taps on all my Commando's :D
I once tried an anti wet sump valve with disasterous consequences (bent conrod & damaged crank etc) :( & would not recommend.
Regards Hursty.
 
Sump oil

Hi all
I rebuilt a friends Commando once & heard at a club night that he was not imprest! Dropped round to find the bike in the shed & the owner giving me an earful. Kicked the bike over for a long while then went through fuel spark gap timing ect knowing it was running well before I had returned it in the van.
I got the full " it cost me XXX & now it wont start, you did a poor job, Christ it didnt even have oil in it when you brought it back"
It was then that the penny dropped!
Drained the extra oil that the hapless owner had added to his oil tank, drained the sump ,cleaned the plugs,started it & left.

PS only ever put a tap in the oil line if you are sure you will turn it on! Busted collar bones toes shoulder plus pelvis & hip damage not to mention the threat of cutting off my leathers put me off doing it!
One scrap bike & a Houdini experience as I took off my leathers for the medical staff!
all the best Chris
 
I have a similar issue guys, had mine for a couple of months, 72 hi rider 5k mi, fresh rebuilt engine by po, claims it ran a couple of months ago.
The bike clearly not getting spark.
I initially added turn signals and a new battery. I’ll kick it all day ..nuthin!
Changed plugs , wires, coils, ign switch
According to the manual, a 72 should have a fourth yellow/blue wire on the switch as well, my ign switch only has three wires attached?
Hate throwing parts at a problem...
Guys I’m stumped
Help from the USA
Christian
 
Last edited:
To surgeon said:
I have a similar issue guys, had mine for a couple of months, 72 hi rider 5k mi, fresh rebuilt engine by po, claims it ran a couple of months ago.
The bike clearly not getting spark.
I initially added turn signals and a new battery. I’ll kick it all day ..nuthin!
Changed plugs , wires, coils, ign switch
According to the manual, a 72 should have a fourth yellow/blue wire on the switch as well, my ign switch only has three wires attached?
Hate throwing parts at a problem...
Guys I’m stumped
Help from the USA
Christian
Click to expand...

Kill switch bad or off ? If not hot wire the ignition.
 
To surgeon said:
How would I check the kill switch?
Click to expand...

With the master switch at the 'Ignition' or 'Ignition and lights' position, there should be battery power in the white/yellow [WY] from the handlebar kill switch (unless the kill button is pressed).

If electronic ignition, what is the make and type?
The kill switch can be bypassed either temporarily for testing (or permanently) but knowing which type of ignition system it has would be useful.
 
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