Problem I Haven't Seen Before

RoadScholar said:
According to the owner it ran for 300 miles..

Best.
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Oh My!

Many many years ago I was a student in a two year diesel tech technical school. One day our instructor said "boys, get your pens and note books and meet me in the class room. I am going to tell you the most important lesson you will ever learn and if you pay attention it will serve you for a lifetime." Of course we ran to collect our writing gear and gained our desks in anticipation of hearing great wisdom. He came in, shut the door, stood in front of the room and said "Here it is. You never build anything with your head up your ass." I remember that lesson to this day and he was right. It's really important.
 
Engines can make more power with the pistons in backwards because of pin offset , as its there to quieten the engine , still needs PV clearance . Disclaimer, I haven't tried it .
 
"head up your ass"

One of my primary flight instructors asked me if it was dark up there whereupon I asked where, sir. His reply: with your head up your ass kid.
 
It's been a while, but this bike will be ready to test as soon as I finally resolve the center stand, I don't remember if I talked about the center stand in this thread. The bottom frame tubes were bowed upwards. Once I fixed that the bike would sit steady on the center stand but with the rear wheel still making contact. The stop points on the stand are worn - they will be built up 1/8" with weld. I tested by putting an 1/8" strip of steel between them and the frame bracket. This caused the stand to be a little more upright and the rear wheel to be off the ground. Also, the bike leans a little to the timing side, so I'll build up the foot of the stand on the timing side.

To see more of the trials and tribulations with this "Ready to Ride - Just needs Servicing bike", look here: https://www.gregmarsh.com/MC/Norton/CustomerCombatBuild.aspx About half way down the 69S starts.
 
Wonder if the Lucas alternator rotors for Triumph's, BSA's and others are marked the same as the ones intended for Nortons?
 
marshg246 said:
I'm about finished with a 69S and ran into a problem. For a change, I didn't do this engine - supposedly "Ready to Ride". Was getting ready to set the static timing and as always checked the timing marks. Thought I was crazy - 22 degree off! Tried a new rotor - 22 degrees off. Switched from the AN timing marks checking tool to a degree wheel - 22 degrees off. When the engine is put at TDC (used piston stop method) the 40-degree mark on the AN tool aligns with 18 degrees. When the engine is put on 30 degrees using a degree wheel, it is off the scale on the timing marks.

I tried both sides to be sure the crank wasn't somehow twisted - both 22 degrees off. I can't see anything wrong with the rotor portion of the crank, but the keyway for the front sprocket was re-cut on the other side of the crank so it went through some issue at some point.

Question: Is there a crank for a different Norton that fits a 71 750 and has the rotor slot in a different place?
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Greg
Is the AN tool you use simply a piston stop or something else?
Cheers
Rob
 
Don't builders check things to make sure everything is right or are they just plain stupid, I always check then double check before moving to the next step, some people should just not go near a motor little lone try to fix one.
 
marshg246 said:
You may be right but since the parts book calls them a "Nut Retaining Plate", the Workshop says to bend them over, there's no reasonable way to use a torque wrench on those nuts, and bikes I know have never been opened had them bent I think it is more likely an urban legend that people are following.
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My 1974 850Mk2A , purchased new ,old stock in July 1976 ,engine did not have these plates bent when I pulled it apart in early November 1976 .I was the original owner from new and this bike had all the faults that could be found ,soft cam , portugese gearbox bearing resulting in the gearbox locking up and then shattering as we slid down the road with rear wheel locked , swing arm bearings with little to no oil and no easy way to oil apart from removing the welch plug . These bearings flogged out in under 6000 miles and in the process ruined the gearbox cradle pivot pin and the gb /swingarm bearing surfaces . Still have parts of this bike . The 850 Mk2A the worst Commando model that Norton made . The model used to get rid of all the factory second rate parts before they moved on to the 850 MK3 . Norton was in a poor financial position at this time and I had a problem with the warranty claim .
 
HRD said:
My 1974 850Mk2A , purchased new ,old stock in July 1976 ,engine did not have these plates bent when I pulled it apart in early November 1976 .I was the original owner from new and this bike had all the faults that could be found ,soft cam , portugese gearbox bearing resulting in the gearbox locking up and then shattering as we slid down the road with rear wheel locked , swing arm bearings with little to no oil and no easy way to oil apart from removing the welch plug . These bearings flogged out in under 6000 miles and in the process ruined the gearbox cradle pivot pin and the gb /swingarm bearing surfaces . Still have parts of this bike . The 850 Mk2A the worst Commando model that Norton made . The model used to get rid of all the factory second rate parts before they moved on to the 850 MK3 . Norton was in a poor financial position at this time and I had a problem with the warranty claim .
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I think you will find that some of the mk3s were also plagued with similar issues that the mk2a had ..being from what I've seen and experienced.... soft cams and failed laysharft bearing ...
Only comment I can say about my own experience with swing arm bushes is that mine was pumped full of grease by the P.O...which was also repaired and replenished with oil as designed ..
 
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Fast Eddie said:
Reed valve breather is a must do IMHO. Either crank case or sump, but def one or t’other.
marshg246 said:
OK, you convinced me (after I checked with Matt :) ). All boxed and ready to send. Turns out that on those with the timed breather he even plugs them when doing the machining.
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FE & Matt are now on my S-List :)

The bike is FINALLY more-or-less done have had its shakedown and little fixes. After the first ride, a puddle of oil formed on the floor - hadn't dropped any since I rebuilt the engine. On banjo was slightly leaking so I tightened it up and tried again - another puddle, but smaller. Absolutely cleaned everything and tightened all oil connections - found none loose. Another run and there were drips on the gearbox - that when I noticed the drip on the bottom of the air cleaner.

The reed valve breather connects to the breather pipe at the top of the oil tank. The internal oil tank breather pipe that runs into the air cleaner ends just across from the engine breather connection. Start wet sumped and oil is shot directly from the engine breather to the open end of the oil tank breather! Fills the tube and then runs into the air cleaner were it slowly drips out.

Now I have to find another way to connect the engine breather to the oil tank - Grrrrrrrrrrrrrrrrr!
 
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