detective work on my new (for me) '74

In cleaning up the bike, I'm finding evidence of the bikes history and previous work done. But I haven't a clue and why some of the work was done in the manner it was.
The seller I bought the bike from said he was the second owner and bought it in '82. Had a transmussion problem. There is evidence that whatever happened to the tranny caused the bike to lock up and go down on it's side.. abraision on the break lever, busted right side drivers foot peg broke replaced with a non-stock folding ped. "Just" a little ding on the tach chrome bezel, Turn signal stalks missing in back and stalks on the headlamp with no lens or housing on the ends. There is a blueing discoloration on the shift lever that looks as if it was bent, taken off the bike and heated with a torcj and bent back to shape.

He didn't recall what exactly what work was done or what actually happened with the transmission, as he went into the military and put in his shed while serving a couple of stints. While he was overseas, his dad took it in for repair. Had it fixed for his son and back into the shed for many more years. Upon arriving back home he bought a Harley as his knee injury wouldn't allow for a kick start. He had it uncovered last year and had his mechanic get it in rideable condition. I just bought it 1 week ago.

The '74 is basically original and has only 7000 miles on it. The frame and the engine have matching serial numbers... 316656. Cleaning it up I found the transmission has a different number 302446 G.
It seems that the "repair work" way back when consisted of a transmission change? That would explain the different serial numbers? At least it's from the same general time frame of manufacture, but I'd like to really ask the mechanic what he did and why... but he is lokg gone. The owners were "check book" mechanics and had no recollection of the nature of the work. The owner was out of the country while the dad brought in the shop (20 years ago) and now the ddad has a bit of Alzheimers onset, So I'll never know the truth.

Another sign of what may have happened when the original tranny went bad, or possibly a mechanis "oops" is that on the inner primary chaincase, the casting that covers the chain around the sprocket is broken off...maybe the mechanis dropped it? Maybe a rock got caught up in there?... just don't know how that breakage could have happened. Another oddity that I will correct is that on the swingarm pivot ends, there is no oil fitting on the right side, and as far as I can see (haven't yet removed the chaincase) is that there isn't one on the left side either... both side have only the flat plug.... kinda odd don't y'all think?.... Also the clutch cable, while it works, is just the wrong one for the bike. I hope the mechanic didn't mess things up in the tranny to get the cable to work....anyways... when I put on the new chaincase, I've got new pivot bearings, pivot spindle caps, "o" rings long thin nut, etc... to bring it to original state. I really don't know what to expect with regards to how the bearings in ther are or if there is any lubrication in there at all...but it will be made right with new parts. Maybe the mechanis that did the work back then was a hack and wasn't familiar with Nortons and forgot the order of dissasembly and had no manual for refference?.

After cleaning off the years of dust, dirt, road grunge, surface rust, this bike is pretty dang nice overall. It's very straight and has cleaned up well. Even righting the wrong on the bike and correcting the "fixes" I will still be ahead on my new "keeper"

Gotta love detective work.

JD

Don't feel bad. My 73 was ridden hard and then had the luxury of being worked over by some jackass Honda shop. We're going through every nut and bolt and making it right. It has certainly been an adventure.

-Jordan

Gday Jeff, with the trans locking up and skidding the bike, sounds like a classic layshaft bearing failure to me! Its widely coverd on the forum if ya search for layshaft bearing failure.
Rgds Foxy

jeffdavison said:

Another sign of what may have happened when the original tranny went bad, or possibly a mechanis "oops" is that on the inner primary chaincase, the casting that covers the chain around the sprocket is broken off...maybe the mechanis dropped it? Maybe a rock got caught up in there?... just don't know how that breakage could have happened.

Click to expand...

That is usually caused by the drive chain breaking, perhaps as a result of the gearbox failure?

jeffdavison said:

Another oddity that I will correct is that on the swingarm pivot ends, there is no oil fitting on the right side, and as far as I can see (haven't yet removed the chaincase) is that there isn't one on the left side either... both side have only the flat plug.... kinda odd don't y'all think?....

Click to expand...

Probably not?

Your Mk2 model has the "sealed for life" pivot where the oil is retained by two felt wicks at either end of the pivot. See the Mk3 exploded diagram for details.

http://www.nortonmotors.de/ANIL/Norton% ... &Plate=016 The felt wicks are items [3] & [12] and welch plug [5].
The sealed for life pivot assembly appears to have been a mid-season change, as the parts are not listed for 1974 and are not in the Mk2 & 2A parts supplement.

I have a one owner '74 that is in pieces waiting for me to bring it back to life. It has the welch plugs on the swingarm as well.

Be glad they put it away and didn't mess with it a lot. Neglect is bad, abuse is worse!

Russ

PS-if that were my chainchase I would repair that flange with epoxy before tossing it out. Its only real purpose is to contain the lube that flies off the chain and it is minimally effective for that.

I'd try it out, carrying lots of tools and tie wraps, tie wire, hose clamps and wiring testing and repair kit and a phone, for at least the first 1000 miles timid testing away for home and tell someone what path you will be found on : (

I've had chain break but it just unwound on road to chase after me like a writhing snake. I've had chain come off many times, d/t worn out sprocket, but it did no damage, just backed up to get it back on and took off with less power till corrected.

Be aware brake fluid can be leaking out on the fly to blow it away till the very next pull down gives nothing at all. Check it on gas stops for 1000 miles to know for sure. Suspect rusted master cylinder piston and caliper pucks.
SS is way to go for ever more. On factory master cylinder I poke burn melt out the tiny pin hole restrictor in the rubber boot valve for better action and feel. Gives me the majority of improvement I got with a smaller resleeve, because the steel piston rust pitted its bore : (

Permanent swing arm lube, ain't true. After servicing might consider the cradle/spindle clamp collars for long term.

There is nothing but normal clutch-cable adjustment to adapt a cable length so nothing to worry on damage that way unless cable rubs stuff wrong or kinked to pull easy.

Lay shaft failure will cause the kicker to swing down, so makes sense a lock up crash that's been fixed inside by proper bearing, maybe.

Suspect fork striction from rusted springs rubbing in side rust stanchions.

All your problems/repairs so far are common and documented. While unfortunate the tranny was replaced instead of repaired.
Thats how it goes.