My *new* 1974 norton 850 starts and dies immediately (2009)

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Matapassiones

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Sep 22, 2009
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Hi All,

I am new to norton ownership and have just picked up a new (was running) project. A week later when kicked it runs for about a second, and quits. Next kick unlikely to yield anything - except fatigue. I have changed nothing from the running state in which I got it. Thoughts????

Thanks!
 
First thought: Gas Starvation
What do the plugs look like after it quits -- Dry or Wet ?
What's the "drill state" you go through to start that first time ?
(i.e., what have you flooded, choked, opened-by-X-amount, etc, etc),
...and do you have both fuel petcocks open?

Second thought: Completely Flooded/leaky floats
What do the plugs look like after it quits -- Dry or Wet ?
Have you dropped the float bowl and checked the floats ?


Third Thought: Anomolous Needle and/or Jet States
Is there white varnish/"goo" from past/old gas in the bottom of the float bowl that's migtated into the jet ?
Have you unscrewed the needle/main jet to see if...
(A) the needle still rises/falls with the air slides?
(B) the jets are clear/blown out top and bottom?
 
First thought: Gas Starvation
What do the plugs look like after it quits -- Dry or Wet ?
What's the "drill state" you go through to start that first time ?
(i.e., what have you flooded, choked, opened-by-X-amount, etc, etc),
...and do you have both fuel petcocks open?

+++Drill+++ 1. 2 petcocks open, tickle x2, kick over once ignition off, ignition on and kick. (don't think I have choke???)

Second thought: Completely Flooded/leaky floats
What do the plugs look like after it quits -- Dry or Wet ?
Have you dropped the float bowel and checked the floats ?

+++PLUGS are wet! - have not dropped float bowl...


Third Thought: Anomolous Needle and/or Jet States Is there white varnish/"goo" in the bottom of the float bowel that's migtated into the jet ?
Have you unscrewed the needle/main jet to see if...
(A) the needle still rises/falls with the air slides?
(B) the jets are clear/blown out top and bottom?

+++I will take a look... thanks for your thoughts...
 
I have the same 74/850. Your problem could be as simple as a flat battery. The 2MC Capacitor [ blue spring mounted cylinder behind battery ] will soak up enough charge to to fire up but not run the bike. The week of inactivity might be enough to discharge a battery in poor condition. Good luck
Greg
 
I would try to choke the carburetors somehow. It may just be that you are tickling a lot of fuel into the floats then introducing it into the combustion chamber so it is appropriately rich for a cold start, and it starts but then it is too lean to continue running without choke. Just a thought.
 
Matapassiones said:
MEHAVEY said:
What kind of carb do you have on it ?
Click to expand...

twin Amals
Click to expand...

Then you have a choke -- by definition.
Do you have the choke lever on the handlebar as thus....?
My *new* 1974 norton 850 starts and dies immediately (2009)

(or did the previous owner remove it?)

Assuming you have it (as evidenced by two cables going to each carb), run your Cold start sequence as follows:

1. Depress/hold the ticklers until gas overflows (you may have to depress several times in some carb/float setups)
2. Open up (counterclockwise) the choke lever all the way (allowing the choke slide to fall down into place & obstruct the carb/slide cutaway)
3. Barely crack the throttle, ...and keep it only cracked as you kick through

Try that... remembering that the engine will run fine on full choke, then 1/2, then 1/4 choke while warming up over a mile or two
 
My guess would be that you need to be sure your battery is hot and install fresh plugs. I base this on seeing several new owners kill their bikes by starting and running on the choke for short times and fouling the plugs. If it was running before all that would be likely to change in a short time is battery and plugs, and the battery must be very good.
 
I like Cookie's read on the battery and plugs. If you don't have one, get a multimeter, $15, and check the battery. You've got a Commando now, you'll need one. You'll be able to find voltage drops, open shorts, resistance that's heat sensitive, (kill switch), all the things that make life interesting. Welcome to the forum, by the way.
 
"I base this on seeing several new owners kill their bikes by starting and running on the choke"

He hasn't used the choke.
 
MEHAVEY said:
Matapassiones said:
MEHAVEY said:
What kind of carb do you have on it ?
Click to expand...

twin Amals
Click to expand...

Then you have a choke -- by definition.
Do you have the choke lever on the handlebar as thus....?
My *new* 1974 norton 850 starts and dies immediately (2009)

(or did the previous owner remove it?)

Assuming you have it (as evidenced by two cables going to each carb), run your Cold start sequence as follows:

1. Depress/hold the ticklers until gas overflows (you may have to depress several times in some carb/float setups)
2. Open up (counterclockwise) the choke lever all the way (allowing the choke slide to fall down into place & obstruct the carb/slide cutaway)
3. Barely crack the throttle, ...and keep it only cracked as you kick through

Try that... remembering that the engine will run fine on full choke, then 1/2, then 1/4 choke while warming up over a mile or two
Click to expand...

Yeah, no choke... my bike has been pretty heavily modified for racing at some point. All sorts of "extras" removed....
 
bpatton said:
I like Cookie's read on the battery and plugs. If you don't have one, get a multimeter, $15, and check the battery. You've got a Commando now, you'll need one. You'll be able to find voltage drops, open shorts, resistance that's heat sensitive, (kill switch), all the things that make life interesting. Welcome to the forum, by the way.
Click to expand...

Thanks so much for your welcome. my first norton!! I had a BSA many years back - never was any good at making that run either.... I 've got a few other bikes and I like taking them apart, but the Norton is now the oldest I've got...
 
One other thing to check: oil level. If it's wetsumped heavily you can get exactly those symptoms - fires right up and then dies and is hard to restart. My 750 drove me nuts with that when I first got it. I didn't know.

If oil level in the tank is low, drain the sump then top off the tank. Never top off without first running the engine or draining the sump.

Hope that helps and good luck,
Debby
 
If it has no choke and is wet sumping that would probably do it too, never thought of that.
 
gregmac said:
I have the same 74/850. Your problem could be as simple as a flat battery. The 2MC Capacitor [ blue spring mounted cylinder behind battery ] will soak up enough charge to to fire up but not run the bike. The week of inactivity might be enough to discharge a battery in poor condition. Good luck
Greg
Click to expand...


Hi many 2MC Cap's are knackered and no one really knows till they test them...removed my choke ASAP after purchase found it a waste of time just tickle till the carbs till fuel appears than turn over whilst opening the throttle quickly to about 1/4 to 1/3 if you overdid the tickle.
 
chris plant said:
how long does it take to fire up again after it dies
Click to expand...

Usually have to let it wait for a few minutes. If I keep kicking, all I do is tire myself out. When it starts up it only runs for a second.
 
In order.....

1. Check battery charge so as to put that behind you
2. Check that engine/oil hasn't "sumped" (if so, drain and dump back into oil tank to put that behind you as well)
3. Drop float bowls check for gooey gunk in bottom, and that float/float needle still propely functional/aligned/seated
4. Open Taps and ensure truly free-flowing fuel from tank
5. Unscrew/inspect/blow clear main & needle jets,... and that needles still rise/fall with throttle operation
6. Reassemble all

7. Flood the hell out of the ticklers to get overflowing fuel evident.
8. Do not open throttle, but barely crack it and keep it barely cracked upon kick-through

9 Kick it through to start -- then open throttle no more than 1/4 to keep it running

10. If it dies, do not kick through more, but pull plugs right then and see if wet or dry.
 
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