I've just stripped the bottom end of the MkIIA that I'm working on. There are no signs that anyone else has been in there, but the lock-tabs - the ones on the two innermost studs that hold the crank together, have never been 'bent over'. Likewise, the others have never been centre-punched either. Since this is a '74, I was wondering if it was symptomatic of the times - i.e. that no-one really cared enough to do the job properly? I'd therefore be keen to hear what other people have found over the years!
Commando Crank Lock-tabs?
- Thread starter Paddy_SP
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Paddy,
I have found my 74 without the locktabs bent over when I did a rebuild. Mind you I bought this bike with about 23000 K on it so I can't say for sure if the crank was ever split. I did find the idler shaft missing from the oilpump along with many leaks. :shock:
Food for thought.
Cheers,
Thomas
CNN
I have found my 74 without the locktabs bent over when I did a rebuild. Mind you I bought this bike with about 23000 K on it so I can't say for sure if the crank was ever split. I did find the idler shaft missing from the oilpump along with many leaks. :shock:
Food for thought.
Cheers,
Thomas
CNN
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Does sound that way, having worked on the Mini assembly line at 30 engines an hour it is easy to go into a trance and forget you have not done the complete work on one engine before going to the next, especially if its the nightshift and you have rushed to see the replay of a goal on the 5 TV's on the side of the track 
. But that's with powered line, I doubt the cranks were assembled on a running track but on a bench with a set target of a number to do during a day, so went for a cuppa and when he came back started on the next crank without finishing the previous one.
. But that's with powered line, I doubt the cranks were assembled on a running track but on a bench with a set target of a number to do during a day, so went for a cuppa and when he came back started on the next crank without finishing the previous one.
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Anyone who has had the clutch nut come loose on their Norton can verify that the tab washers are pretty much worthless when it comes to keeping a nut in place. About the only value that tab washer has is keeping the center pin from falling out when the hole was bored a little too big.
The tab washers are made of a very soft material that squashes under the load of the nut. This will insure that the stud will not be under the correct torque after the crank has flexed a few times. I would suggest throwing the tab washers away and using wicking grade locktite on the nuts and the pin. Jim
The tab washers are made of a very soft material that squashes under the load of the nut. This will insure that the stud will not be under the correct torque after the crank has flexed a few times. I would suggest throwing the tab washers away and using wicking grade locktite on the nuts and the pin. Jim
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Yes ,discard the bend over tabs and use that Loctite after MEK or Brake spray carefull cleanings of nuts and bolt threads. Use Ventilation. Remember reading in the paper about a Cadillac owner returning the new car with a rattle-clunk sound in door every closing. Lots of head scratchings until opening it all up to find an empty mickey bottle of whisky. 
Also sloppy Norton stuff : MK 111 timing cover anti drain valve : Not machined out , and plunger and spring not fitted ( Nothing to fit it into ! ).. 
Also sloppy Norton stuff : MK 111 timing cover anti drain valve : Not machined out , and plunger and spring not fitted ( Nothing to fit it into ! )..
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Forget everything. It's 2015 , almost 16 ( soon ). Modern seals . , chemicals , sealants , etc. Center-punching rude , brutal. Soft bend -over tabs obsolete. Do you want a bolt separating and crunching up your precious crank ?
htown16
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Comnoz, do you have a number on the locktite you recommend? Just nuts on one side or both on the 850 studs and nuts. Will be rebuilding from scratch so not intace and probably no need for wicking. I just stripped my 74 850 crank yesterday and the tabs weren't bent over either.
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htown16 said:
Looking at the tube I have here. It is Permatex brand "Threadlocker Green -penetrating grade" item #29000
There is also a locktite branded product. Green #290.
It can be applied to the bolts after assembly and it sets up fast so I wouldn't use it until they are torqued. Jim
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Interesting information, thanks.
I'm building up my crank in a couple of days and I'll give the Loctite green 290 a go....I've just ordered it.
It sounds like a better way than putting Loctite 243 on all of the threads and having it starting to go off before finishing torqueing it all up and leaving me wondering if the torque settings had been affected.
I'm building up my crank in a couple of days and I'll give the Loctite green 290 a go....I've just ordered it.
It sounds like a better way than putting Loctite 243 on all of the threads and having it starting to go off before finishing torqueing it all up and leaving me wondering if the torque settings had been affected.
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A reminder rod nuts are one time use only , and head for the trash bin each and every removal. Loctite a good idea not found in manual. 
robs ss
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I agree - loctite plus punch is best to secure the bolts/studs.
My belief is the "tabs" primary purpose is to stop the dowels coming out - so... very important role.
Cheers
concours
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I would say it's ONLY purpose in that usage.
marshg246
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If the only role is to keep the dowel in place, then AN should quit making them tab plates - would cost much less to just make them rectangles with holes. Then we should get in the way back machine and fix the workshop manual and the parts manuals. While we're at it, in Aug 73 Norton released N3/67 where they show their love for thread locking yet no one is mentioning the factory using thread locker with unbent tabs - seems like a little more time in the way back machine could fix more. Also, I've seen no evidence of the factory punching the crank or conrod nuts.Another thing. Has anyone seen one of these tabs broken? Does everyone know that they are one-time use (all tab washers are)?
I find it funny that Norton tabs = bad but Triumph and BSA tabs remain good, and that I've had no personal evidence of any tab failing since 1968
New proposal. Notice that the above is "quoted" with smiley faces - in other words, don't get triggered - just a little levity mixed in with thoughts.
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