Hi, new to Commandos but now have two!

worntorn said:
Still running bad old Boyer MK3 on my Mk3. I wanted to stay with the matching numbers and letters.
I've never heard a kickback from it but I don't bother trying to estart with a low battery.
Fearful of the dreaded kickback, a few years ago I installed a tiny second battery on its own isolated ignition circuit just to provide full voltage at cold startup.
Most of the time I forget to use it!

Glen
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Glen,
There is nothing wrong with the Mk3 Boyer as long as it always gets 12 volts. Anything lower and it starts doing weird things to the timing.
 
CanukNortonNut said:
Glen,
There is nothing wrong with the Mk3 Boyer as long as it always gets 12 volts. Anything lower and it starts doing weird things to the timing.
Click to expand...
Dyno Dave stated the cutoff point as 10.8V where he showed the timing will vary plus or minus proportional to the volts below that figure and ultimately it will quit at 6.5V.
Hi, new to Commandos but now have two!
 
Yes, I've run it for the 20 years I've owned the bike, no problems with kickback. I just make sure to keep a good battery in there. That's something one wants to do anyway for many reasons, not the least of which is to keep the sprag healthy.

My thinking was that, even though the other ignitions mentioned are an upgrade, they aren't really needed if the OP is on a tight budget.
The MK3 Boyer was installed on the bike in mid 80s by Poke's Cycles, so it's coming up on 40 years of use.
I haven't touched it while I have had the bike.
Watch, now it will fail next week!

Glen
 
"I just make sure to keep a good battery in there. That's something one wants to do anyway for many reasons, not the least of which is to keep the sprag healthy."
Glen, You said it all right there.
Feed the Boyer Mk3 12 volts and its happy. But how many MkIII E. start riders do that? They will blame the bloody thing because their bike got more damage.
I was just nudging the OP for some added insurance to keep the sprag healthy, with a suggestion to an updated alternative E.I.
We are both on the same page!
Cheers,
Tom
 
Hi All,
Quick update. New master cylinder is installed. Slightly bigger reservoir than the last unit but otherwise identical.
Drained the sump to verify it wasn’t dry dumping. Nope. There is a manual quarter-turn valve on the oil line but even after leaving that on all night the oil was minimal.
Cleaned the carb hypersonically with Pine-Sol, guitar strings, and patience. Kept the same 230 main jet in it. Can’t read the needle beginning but it ends with 6Dh3, clip 3rd position. Needle jet Q-5. I’m at 3,000”. Previous owner was sea level.
Compression 130/135
Plugs BP7ES. Carbs were oil fouled but looked really new. Cleaned them off and put them back in. Visual spark in daylight.
Bike won’t start. Only backfires on both pipes.
On inspection both plugs oil fouled again.
Other than that, general clean-up of the bike. It’s looking much better after brass wool, polish, simple green and patience.
Looking t the front brake, it hasn’t been used. I’m stymied on how the original master culinder became so corroded. There was zero brake fluid on it, the slave, or the hydraulic lines. It looks like the system was bolted on and then never had brake fluid on it.
Thank you for all your thoughts above. Pretty helpful.
Dan
 
I started digging through a box of spare parts for the bike and found this Nortec AMR modification sheet. I researched it to find out what it is.
 
Shackkat said:
I started digging through a box of spare parts for the bike and found this Nortec AMR modification sheet. I researched it to find out what it is.
Click to expand...

AMR still do this mod - very good for pre-MkIIIs
 
Checked the valves tonight and found them slightly tight. About a thousandth, not enough o cause a difference. I’ll change out the Mkiii to a Mkiv if that doesn’t work the top end will come off to inspeact the valves and cylinder
 
robs ss said:
Here's my experience with AMR - I am very happy👍
Mar 3, 2023
Cheers
Click to expand...
Look at the "dolls head" on the inner primary. The weight of the electric starter can induce a fracture around the mounting. One cylinder of the Norton is nearly the same volume as a 441. Couldn't tell you which is more frightening to have a kick back...
robs ss said:
Here's my experience with AMR - I am very happy👍
Mar 3, 2023
Cheers
Click to expand...
 
Shackkat said:
Thank you. Looks like a 40mm 8mm bolt will do the trick. I appreciate the link!
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Anything threaded into a cycle part will likely be SAE or possible British. Nothing on a production Norton was ever metric. That said I don’t know anything about after market parts.
 
ILLF8ED said:
Anything threaded into a cycle part will likely be SAE or possible British. Nothing on a production Norton was ever metric. That said I don’t know anything about after market parts.
Click to expand...
Yep. I am used to wentworth tools. In this case, the aftermarket bolt was metric.
 
ILLF8ED said:
Anything threaded into a cycle part will likely be SAE or possible British. Nothing on a production Norton was ever metric. That said I don’t know anything about after market parts.
Click to expand...
Points and gearbox covers are 2BA which is metric. Likely the carb screws are as well.
 
ILLF8ED said:
SAE
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Unified (UTS since 1949) including UNC which apparently never was an SAE thread.

United States Standard thread - Wikipedia

en.wikipedia.org en.wikipedia.org
"The Unified Thread Standard uses the term UNC (Unified Coarse) to describe a fastener that previously would have been designated USS and UNF (Unified Fine) to describe a fastener that would have previously been designated SAE."
 
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