Living with a Mk III starter

scott12180 · Sep 15, 2011

Lots of people claim that the original starter on a Mk III is no good, and granted it's pretty marginal, but mine works just fine. My bike is all original with somewhere between 15,000 and 30,000 miles (speedo was replaced).

If you have an original starter and all the gearing is good, but it just never seems to have enough oomph to turn the engine over, do these two things:

Get a modern Gel Cell battery. Mine is an Odyssey. Honestly, they work great. Why they seem to work better than a conventional battery, I don't know. Somehow they put out more charge.

Double and shorten every wire which goes to the starter. You'll have two black wires --- one to the solenoid and the other from the solenoid to the starter. On my bike, I got away cutting both in half, and running the two halves in parallel. Do the same for the red "ground" wire. If yours can't be cut in half, find a similar gauge wire and run it in parallel.

What this does, by halving the length, if possible, you half the resistance of the wire. By running two wires in parallel, you double the cross sectional area of the wire, which also halves the resistance. The result is 1/4 of the original resistance. Stupidly when I did this I forgot to measure the before and after resistance, but the result is quite noticeable. My starter really seems quite energetic. Remember, that's also partly due to the Odyssey gel call battery.

--Scott
'75 Norton Commando Mk III Roadster.

L.A.B. · Sep 15, 2011

scott12180 said:
Double and shorten every wire which goes to the starter. You'll have two black wires --- one to the solenoid and the other from the solenoid to the starter. On my bike, I got away cutting both in half, and running the two halves in parallel. Do the same for the red "ground" wire. If yours can't be cut in half, find a similar gauge wire and run it in parallel.

Fitting a set of heavier gauge single cables would be preferable, in my opinion.

scott12180 said:
Odyssey gel call battery.

Odyssey batteries are AGM (Absorbed Glass Mat) type, I don't think they make any "gel" batteries.
http://www.odysseyfactory.com/documents ... 11_000.pdf

nortonspeed · Sep 15, 2011

Well I guess you are one of the happy few because you can replace most of the weak parts (battery, cables, starter motor) but unfortunatelly there is no replacement for the vulnerable sprag system which keeps on failing to me time after time

powerdoc · Sep 15, 2011

I fitted a 4 pole to mine primarily because the damn thing is just hard to kick! Maybe I need to gain weight.

comnoz · Sep 15, 2011

scott12180 said:
Lots of people claim that the original starter on a Mk III is no good, and granted it's pretty marginal, but mine works just fine. My bike is all original with somewhere between 15,000 and 30,000 miles (speedo was replaced).

If you have an original starter and all the gearing is good, but it just never seems to have enough oomph to turn the engine over, do these two things:

Get a modern Gel Cell battery. Mine is an Odyssey. Honestly, they work great. Why they seem to work better than a conventional battery, I don't know. Somehow they put out more charge.

Double and shorten every wire which goes to the starter. You'll have two black wires --- one to the solenoid and the other from the solenoid to the starter. On my bike, I got away cutting both in half, and running the two halves in parallel. Do the same for the red "ground" wire. If yours can't be cut in half, find a similar gauge wire and run it in parallel.

What this does, by halving the length, if possible, you half the resistance of the wire. By running two wires in parallel, you double the cross sectional area of the wire, which also halves the resistance. The result is 1/4 of the original resistance. Stupidly when I did this I forgot to measure the before and after resistance, but the result is quite noticeable. My starter really seems quite energetic. Remember, that's also partly due to the Odyssey gel call battery.

--Scott
'75 Norton Commando Mk III Roadster.

I have to agree. I have a stock MK3 with around 20,000 miles. The only modification is the addition of an Oddessy battery. [It is a spiral wrapped AGM battery and not a gel cell however.] It has always started reliably since I went for an Oddessy battery- even if it sets for a couple months. With the standard wet cell it would only start when everthing was perfect. Jim

Jeandr · Sep 15, 2011

nortonspeed said:
... but unfortunatelly there is no replacement for the vulnerable sprag system which keeps on failing to me time after time

Alton is working on replacements for those

Jean

rond944 · Sep 15, 2011

Jeandr said:
nortonspeed said:

... but unfortunatelly there is no replacement for the vulnerable sprag system which keeps on failing to me time after time

Click to expand...

Alton is working on replacements for those

Jean

Well tell them to hurry up

My 10:1 880 is almost finished . I've already got the
dyno dave starter , heavier cables , and plan to get an odyssey battery .

nortonspeed · Sep 16, 2011

Jeandr said:
nortonspeed said:

... but unfortunatelly there is no replacement for the vulnerable sprag system which keeps on failing to me time after time

Click to expand...

Alton is working on replacements for those

Jean

Can't wait to get that Alton replacement

john robert bould · Sep 16, 2011

L.A.B. said:
scott12180 said:

Double and shorten every wire which goes to the starter. You'll have two black wires --- one to the solenoid and the other from the solenoid to the starter. On my bike, I got away cutting both in half, and running the two halves in parallel. Do the same for the red "ground" wire. If yours can't be cut in half, find a similar gauge wire and run it in parallel.

Click to expand...

Fitting a set of heavier gauge single cables would be preferable, in my opinion.

scott12180 said:

Odyssey gel call battery.

Click to expand...

Odyssey batteries are AGM (Absorbed Glass Mat) type, I don't think they make any "gel" batteries.
http://www.odysseyfactory.com/documents ... 11_000.pdf

LAB, ON THE NAIL.I attempted to lead start my other bike,the cheapo leads would not carry the load, borrowed some truck leads and bingo...full flow.
Just shows how "thinner" cable as to much resisttance!

john robert bould · Sep 16, 2011

rond944 said:
Jeandr said:

nortonspeed said:

... but unfortunatelly there is no replacement for the vulnerable sprag system which keeps on failing to me time after time

Click to expand...

Alton is working on replacements for those

Jean

Click to expand...

Well tell them to hurry up My 10:1 880 is almost finished . I've already got the
dyno dave starter , heavier cables , and plan to get an odyssey battery .

Ermmmm....£1000 plus English Pounds.....I kick start my M3 . for Nothing. Anyway only girls and whimps require Lec'ie Boot :lol:

nortonspeed · Sep 16, 2011

[/quote]Ermmmm....£1000 plus English Pounds.....I kick start my M3 . for Nothing. Anyway only girls and whimps require Lec'ie Boot :lol:[/quote]

Well my girl doesn't require Lec'ie Boot, she kicks my Commando and ass. But not everybody is blessed with strong leggs at a certain age :wink:

donmeek · Sep 16, 2011

when i bought my mk111 from Boston Cycles in '75, the e start didn't work worth a damn. I brought it in for it's 500 mile service and complained about it. I was told that it was actually a "starter assist" and wasn't meant to start the bike on its own. Can you imagine that? it's really no big mystery why they eventually folded. Anyway, around 1980 or so, a friend of mine who ran the local Mobil garage told me to put the biggest battery I can find in it (mk111 airbox removed), replace all the cables with #4 or #6, and that would solve the problem. He was right. Also, it is very important to get the tuning/ timing spot on to prevent kickbacks, which will destroy the sprag. The starter should spin by just barely touching the button for a tenth of a second. But you guys are right, when it starts on one kick, who needs a starter? I use mine primarily when stuck in traffic or stalled on a hill. nice to have that option.

rond944 · Sep 16, 2011

Yeah , I too kick mine most of the time , but want the option
of using the button when it quits in traffic , or it's not convenient
to pt up on the center stand , or I'm in a hurry .

I was concerned about the 880 engine at nearly 10:1 but my
friend who has a stock mk3 told me his recently acquired
VR 880 is at least as easy to kick as his stock mk3 so I'm
optimistic mine won't be too bad . Perhaps the longer cam
timing helps reduce the low speed cranking compression .

Brithit · Sep 16, 2011

rond944 said:
Yeah , I too kick mine most of the time , but want the option
of using the button when it quits in traffic , or it's not convenient
to pt up on the center stand , or I'm in a hurry .

+1. In addition to a quick handy start up in traffic - especially two up, I mostly use mine when somebody asks me if it works! I do remember asking my wife to hop off the back in the middle of 5 o'clock traffic, so I could re-start my '74 years ago. She wasn't that impressed! I know the sprags aren't always the longest lasting things, but I just figure if I use mine a minimum amount of time, it'll last until I'm old and can't kick it anymore. By then, I may not care about the whole thing - but I doubt it.

ETA - I have a Dave Comeau starter & cables and an Odyssey PC545 on a pre-MKIII battery tray with my own wiring harness and a lovely Speed Triple starter button. Works a treat!

Living with a Mk III starter

scott12180

L.A.B.

Moderator

nortonspeed

Guest

powerdoc

comnoz

Jeandr

rond944

nortonspeed

Guest

john robert bould

john robert bould

nortonspeed

Guest

donmeek

rond944

Brithit

Similar threads