MY Commando won't stay running...

SierrasCafe530 · Apr 30, 2012

I took out my 73 Norton Commando 850 yesterday and she ran strong. A little poping when declerating and sputtering a little when I got on the throttle real hard. Today I went to start her and she fired up after a few kicks but cut out as soon as I took off the choke and put her in gear. This happened a few weeks ago too and it was the timing. I put a boyer electronic ignition in her so why does her timing keep getting retarted? I don't know where to go. I'm not a very seasoned mechanic... Is the a good one in the sac/Chico area of Nor Cal? Help please!

gory · Apr 30, 2012

Are you running Amal carbs? If so, are you sure the choke is off? it is actually off when the cable is tight, ie you pull the lever to disengage the choke. That caught me out once too, and I still have to think about it on occasion.

SierrasCafe530 · Apr 30, 2012

I do believe that my carbs need to be better adjusted however it doesn't account for my timing issue... My frustration is at its max with this project. It has been one thing or another. I have yet to be able to rely on her. I've only been able do go on short rides.

Steve D · Apr 30, 2012

I have a 1973 850 and I had a similar problem. The bike would start and tick over but when I pulled away it would either stall or run really poorly for around a mile, after which it would clear and run cleanly. I put in new NGK plugs and cleaned the carbs right out. I got a proper C spanner and re-set the exhausts in the head. I don't have the problem anymore but I'm not sure which of the things I did cured it, my suspicion is the amals. The left carb takes ages to flood (about a minute) when I use the tickler. After stripping and rebuilding the carb will flood easily for about a week and then slow right down again. I don't know if that helps but it worked for me.

dave M · Apr 30, 2012

If the timing is slipping, then the taper between the boyer magnet holder and the cam may need to be lapped in with fine grinding paste, a taper is a very tight fit if the two part correspond, but if not or if the mounting bolt is insufficiently tight then it can come loose.

SierrasCafe530 · Apr 30, 2012

dave M said:
If the timing is slipping, then the taper between the boyer magnet holder and the cam may need to be lapped in with fine grinding paste, a taper is a very tight fit if the two part correspond, but if not or if the mounting bolt is insufficiently tight then it can come loose.

I thought that might be the issue. I've been meaning to get some thread lock for it.

SierrasCafe530 · Apr 30, 2012

Steve D said:
I have a 1973 850 and I had a similar problem. The bike would start and tick over but when I pulled away it would either stall or run really poorly for around a mile, after which it would clear and run cleanly. I put in new NGK plugs and cleaned the carbs right out. I got a proper C spanner and re-set the exhausts in the head. I don't have the problem anymore but I'm not sure which of the things I did cured it, my suspicion is the amals. The left carb takes ages to flood (about a minute) when I use the tickler. After stripping and rebuilding the carb will flood easily for about a week and then slow right down again. I don't know if that helps but it worked for me.

Interesting. A lot Of these issues happened after I put strait drag pipes on her. I just rebuilt my carbs a couple months ago and put new NGK plugs, caps and wires. I always use my ticklers when starting my amals so I may be flooding her out. Idk

dave M · Apr 30, 2012

Loctite wont do the job in this application, you simply need to remove the magnet holder put some fine grinding paste on he taper and move it clockwise and couterclockwise in the taper with a bit of pressure on it. If you wipe off the paste after a short stint you can see by the matte and shiny bits how much mating surface there is. Matte means good surface coverage.

Hobot · Apr 30, 2012

I've had this happen a bunch of times on my Combats, a good many of them turned out to be loose carb/manifold fasteners or float bowl screws loose or gone. Check Balance tube and try the wd40 or propane sprayed at intake seams to see if idle changes. Its possible Amal jet backed out and can't forget Boyer trigger wires broken inside or other wires even brake light area. Always buy a V8 box of plugs as one must always put new ones in just in case and even then can't trust new ones out the box so twice change before focusing on more likely issues. For some strange reason I can rationalize a number of factoids on, seems too often after I've had some mis-fire issues d/t igniton, intake or electrical like bad battery, plugs seem to fail about then too. Maybe carbon layer shorts em so new plugs have gotten me going again, after the real problem fixed but still same symptoms, ugh.

rpatton · Apr 30, 2012

Mr. Guido please pick up the white courtesy phone.

Most of the members in the NCNO are in the Bay Area, but there's some in your neck of the woods.
http://www.nortonclub.com/

SierrasCafe530 said:
I don't know where to go. I'm not a very seasoned mechanic... Is there a good one in the sac/Chico area of Nor Cal? Help please!

gory · Apr 30, 2012

SierrasCafe530 said:
I do believe that my carbs need to be better adjusted however it doesn't account for my timing issue... My frustration is at its max with this project. It has been one thing or another. I have yet to be able to rely on her. I've only been able do go on short rides.

I didn't ask how they were adjusted, I asked if you were sure the choke was 'off' - just because it was the timing a few weeks ago, doesn't mean it still is.

SierrasCafe530 · Apr 30, 2012

gory said:
SierrasCafe530 said:

I do believe that my carbs need to be better adjusted however it doesn't account for my timing issue... My frustration is at its max with this project. It has been one thing or another. I have yet to be able to rely on her. I've only been able do go on short rides.

Click to expand...

I didn't ask how they were adjusted, I asked if you were sure the choke was 'off' - just because it was the timing a few weeks ago, doesn't mean it still is.

Im not sure... It seems tight enough when i turn it off. I've been told to just remove the thing, but i kind of need it to start her up. I feel if i get the carbs adjust right i might be able to get rid of it.

pete.v · Apr 30, 2012

SierrasCafe530 said:
Im not sure... It seems tight enough when i turn it off. I've been told to just remove the thing, but i kind of need it to start her up. I feel if i get the carbs adjust right i might be able to get rid of it.

Get rid of what?

SierrasCafe530 · Apr 30, 2012

pvisseriii said:
SierrasCafe530 said:

Im not sure... It seems tight enough when i turn it off. I've been told to just remove the thing, but i kind of need it to start her up. I feel if i get the carbs adjust right i might be able to get rid of it.

Click to expand...

Get rid of what?

The choke...

AussieCombat · Apr 30, 2012

Hey sierrascafe530,
Popping on deceleration can mean a lean mixture at idle.
Unless you have changed something, probably caused by a partially blocked Idle circuit.
Starts with the Chokes on, but stops when chokes are opened up...
Also indicates a leaness, and could point towards a blocked Idle circuit.
Try to keep it running with the Chokes partially on, that will tell you
if it is Carby related.
Definately check that the Manifolds are tight, but not too tight., as these Amals can warp
and create an air leak which then leans the mixture off.
Don't throw the Chokes away, in my oppinion I think they help to keep worn slides
from bouncing around inside the carb.
It's true that once Amals are tuned nicely and stay that way, then the Chokes aren't
really necessary, how ever if youv'e got them, keep them.
If the Carbs are getting blocked repeatedly, clean the tank out and check your filters.
Of course it might be electronic.
AC.

pete.v · Apr 30, 2012

SierrasCafe530 said:
pvisseriii said:

SierrasCafe530 said:

Im not sure... It seems tight enough when i turn it off. I've been told to just remove the thing, but i kind of need it to start her up. I feel if i get the carbs adjust right i might be able to get rid of it.

Click to expand...

Get rid of what?

Click to expand...

The choke...

Good idea. They make blanking screws just for that purpose.

SierrasCafe530 · Apr 30, 2012

AussieCombat said:
Hey sierrascafe530,
Popping on deceleration can mean a lean mixture at idle.
Unless you have changed something, probably caused by a partially blocked Idle circuit.
Starts with the Chokes on, but stops when chokes are opened up...
Also indicates a leaness, and could point towards a blocked Idle circuit.
Try to keep it running with the Chokes partially on, that will tell you
if it is Carby related.
Definately check that the Manifolds are tight, but not too tight., as these Amals can warp
and create an air leak which then leans the mixture off.
Don't throw the Chokes away, in my oppinion I think they help to keep worn slides
from bouncing around inside the carb.
It's true that once Amals are tuned nicely and stay that way, then the Chokes aren't
really necessary, how ever if youv'e got them, keep them.
If the Carbs are getting blocked repeatedly, clean the tank out and check your filters.
Of course it might be electronic.
AC.

I don't have any filters because i have a fiberglass sealed tank. I need to find someone in my area to get my carbs right. I just can't figure these Amals out. I have adjusted the slides, the air screw, ect... If I leave the choke on, she boggs to much so I always warm her up with it on and turn it off when I take off out of my driveway. I just get frustrated so fast because being that shes an 850, shes heavy. Every time she cuts out, I have to get off, put it on the center stand, kick it two three time and pray she stays running. After about four times of this I'm warn out and sweating like hell in my moto jacket and helmet.

Could it be the Strait Pipes Drag pipes on it?

Here is a pic of the pipes...

DogT · Apr 30, 2012

Yes, Amal carbies will not work with the straight pipes. Don't know why you want them any how, the peashooters are so cool and you're not a loud dick.

I think others can attest to straight pipes. I had some Hooker glass packs that didn't work with the Amals either. Seem to like a bit of back pressure to work right.

Oh, well.

dog

SierrasCafe530 · Apr 30, 2012

DogT said:
Yes, Amal carbies will not work with the straight pipes. Don't know why you want them any how, the peashooters are so cool and you're not a loud dick.

I think others can attest to straight pipes. I had some Hooker glass packs that didn't work with the Amals either. Seem to like a bit of back pressure to work right.

Oh, well.

dog

I was told they will work, I just need to run it richer... Oh and since I'm a girl, I guess that would make me a Loud bitch, not a dick. lol... They are not all that loud anyways.

swooshdave · Apr 30, 2012

SierrasCafe530 said:
I was told they will work, I just need to run it richer... Oh and since I'm a girl, I guess that would make me a Loud bitch, not a dick. lol... They are not all that loud anyways.

I'll be right back, I'm making popcorn. This is going to get good. :mrgreen:

MY Commando won't stay running...

Similar threads