Oil pump worm drive nut

Does anyone know an easy way of locking up the crank so I can undo this nut?

Mine is locked solid. I've tried using the back brake with the bike in top gear and also locking up the camchain (which stretched - new chain now needed :cry: ) but there's no way it will move.

Yes I know the nut is a left hand thread :lol:

The bike is presently fully assembled except for the timing cover being off

I think that it needs to be a rag stuffed between the crank pinion and the intermediate gear, although it would be best if its spindle was supported.

I suspect that it will need a shock.

I'll try that one next thanks. Used a shock last time - belted the end of the socket bar with a 7lb hammer - that's how the timing chain got stretched.

Just a thought Mike, but why does it need to come off for anything apart from splitting the cases ?

Its like a variation on the recent posts on a bike not starting after a rebuild. Just finished replacing the barrel, pistons etc after resleeving, recutting valve seats in head etc. I also fitted a new timing chain while the barrel was away as the old chain had a bad slack spot which caused the timing mark never to hold steady when when setting the timing up with a strobe.

Finished the engine rebuild last night and tried to start the bike this morning - nothing at all not the slightest sign of firing. The sparks and fuel are all 100% OK. Next step I checked down the plug holes with a torch and I seem to have the inlet valves opening on the compression stroke when the pistons are on the way up. So the valve timing is out and I think that despite checking so carefully when fitting the new chain that something is wrong in that area?

Next off comes the timing cover. The timing chain marks are correctly set 10 links apart so my next thought is the timing mark on the pinion gear must be misaligned. You cant see this mark without removing the timing chain and gearing and as only way to get the timing chain off to check is to remove the oil pump and worm drive nut ............see where I'm coming from.

The really annoying part is I fitted that wormy nut only two weeks ago and the engine has never been run since I did it!! Plus I've recked a brand new timing chain!!! GRRRR!! It's not the xpense but the aggravation of having the bike finished, or so I thought, last night and now theres bits all round the garage again :cry:

I understand your frustration Mike and also why the nut is so tight - It hasn't had time to shake itself loose

I always put a splodge of paint by the timing marks so that I can more or less see them in situ. Otherwise I begin to doubt myself as soon as the nut's on :?

Yeah I do as well - always use Tippex - but kicking the bike over this morning, plus it was still all a bit oily when I put the Tippex on so it didn't stick too well, has erased the dots I put on the gear pinion behind the chain sprocket and the one on the crankshaft pinion.

The annoying bit is I can still see the dots I put on the chain to line that up and I can still count the links without the marks!! Why is it the ones you need seem to dissapear first?

I would not try to shock the oil pump worm nut loose. My crankshaft had only one shallow drilled balance hole which is how the manual describes to lock the crankshaft to remove both timing nuts. I did not fabricate a plate to support the intermediate gear shaft as I was in a hurry to strip down the engine and get it back on the road ASAP. More haste less speed as they say and at my age I should know better. Anyway the result of to much force was the intermediate shaft moved in the crankcase and I then had to set up the crankcase in the milling machine and bore the case oversize, machine a bush and shrink fit it into the case to ensure the shaft was a tight fit so I could set the cam chain tension without it moving all over the place which the loose intermediate shaft would cause and the timing gears would wear abnormally. Much easier to fabricate the plate I made yesterday when I got around to refitting the timing chain at a slower and less stressfull pace. I should have listened to the superviser [wife] and stoped the rushing which only ends up in tears.[mine]. I had fitted the cylinder to the crankcase so the only way I could hold the crankshaft was to fit the rotor key in the shaft and hold it with a large shifter. I had concerns about how much force to apply without twisting/ flexing the crankshaft as I could not find torque settings in my manual.
Ian

Scruff said:

Anyway the result of to much force was the intermediate shaft moved in the crankcase and I then had to set up the crankcase in the milling machine and bore the case oversize, machine a bush and shrink fit it into the case to ensure the shaft was a tight fit

Click to expand...

Guess what - I think I've got that sort of major problem. Just taken off the head/barrel/pistons again, locked the engine up and got the worm drive nut off. Then removed the timing chain/intermediate gear and camshaft sprocket and discovered the intermediate gear shaft is loose in the crankcase.

Is the shaft meant to be totally solid at the end when you rock it from side to side or can you get away with about 2mm horizontal movement measured at the end of the shaft? There is zero vertical movement. I've checked what looks like an insert of some kind with the circlip fitted that the shaft fits into in the crankcase and nothing appears to be damaged or cracked.

It may have been this has been like this since I bought the bike 2 years ago as this is the first time I have stripped the timing chain area and specifically checked for play in this shaft.

Possibly looks like the only way to sort this one is to take the engine out split the cases and get a new bush fitted as you did. I've not got the use of any workshop machines myself so I think it will have to be a send away job to sort this.

Anyone got any suggestions???

Did you find your problem Mike ? Was the cam timing out ?

I have no experience of loose intermediate spindles. It does need to be a good fit but it is of course supported by the dowelled-on outer cover as well.

The NOC Service notes have this to say :-

"The spindle for the idler gear should be tight in the cases. If not, dry the cases off thoroughly and warm with a blowlamp before refitting the spindle with a drop or two of 'bearing Fit' Loctite. If it has been turning and will push in cold, copper plate it to a thou or two of interference and try again. (Have about five thou plated on and rub down to the required size with worn-out emery). Nickel or chrome are too hard to rub down and must be ground to size).

The oil hole goes underneath with the slot in the outer end horizontal."

Are there any ideas here that will work for you ?

The cam timing was out - don't know how but I managed to get the dots missaligned between the intermediate spindle and the timing pinion gear when I fiited the cam chain - got to blame it on old age, bad lighting in the garage, oil on my specs or a combination of all three. The problem was so obvious when I looked down the plug holes!!

Like the ideas in the NOC Service notes - keep forgetting to have a look at those.

The way the spindle fits in the case it seems there's a slight ovality in the housing but not a massive amount. Using stud and bearing fit is the easiest idea but I've never tried it for something with quite as much play as this. Got some in the tool box so will give that a bash tomorrow after I track down one of my mates to borrow his blowlamp to warm the case. Doesn't look like the spindle has been turning so hopefully plating may not be needed and the loctite will do the job.

Must admit I hadn't thought about the other end of the spindle being supported in the outer case - was thinking it was in the oil seal but that's the end of the crank in there of course

On Tuesday will go out and restock on more gaskets for head, barrel base, oil pump, covers, rockers, ..........etc etc. again and start reassembly or if the weather is half reasonable I'll just pick up all the bits and then get my 916 out and have a good blast to blow these Nort problems out of my mind for a bit.

I'll return with an update when the stud and bearing fit has cured - hopefully rock hard.

What you're describing is why I check myself twice on everything these days. It's also probably the reason why I always buy at least double of all oil seals and gaskets !

Have you got away with no piston to valve contact ?

I still like the old NOC Service Notes. They're a bit chaotic but the solutions are real world and the bikes were not considerd too precious then.

You have nothing to loose by trying loctite and some varieties can accept quite a bit of clearance. The usual thing of making sure its completely free of oil traces and whack the outer cover on with a couple of screws to ensure alignment while it sets. (By 'whack' I mean the colloquial 'shove it on quickly', not hit it with a hammer or anything before anyone not from the south of England queries it )

On removal of the nut--remove a spark plug and rotate the engine so the nut removal direction is rotating the same as the crank with the piston rising---then begin stuffing a 1/2" dia. very long section of clean nylon rope into the cylinder.
Stuff as much as you can but leave enough out to be able to pull out.
This will create a soft hydraulic lock on the engine and you should then be able to remove the nut.
I have used this technique several times-with good results--just use a steady firm pressure on your removal tool---a long cheater works well--
DO NOT use a hammer to shock it loose--this is when s**t happens.
If you are not comfortable doing it this way---take your bike to someone who has Norton mechanical experience.

79x100 said:

Have you got away with no piston to valve contact ?

..................

(By 'whack' I mean the colloquial 'shove it on quickly', not hit it with a hammer or anything before anyone not from the south of England queries it )

Click to expand...

The valves just kissed the tops of the pistons and slightly marked them. I've had all the valves out and checked them and none are damaged. The bike was turning over full cycle freely on the kickstart so I was lucky there.

..................

We use 'whack' up here in the Midlands as well - but probably 'bang' it on is more commonly used but still open to the same misinterpretation

mike916sp said:

I'll return with an update when the stud and bearing fit has cured - hopefully rock hard.

Click to expand...

Got hold of my mates blowtorch warmed the case and intermediate gear shaft and refitted the shaft in crankcase with Loctite stud and bearing fit and loose fitted the outer timing case to keep shaft aligned as suggested. Eight hours later just removed the outer case and the shaft is now rock solid in the crankcase housing

So its out to get my gaskets etc tomorrow morning and hopefully the Nort should be running again by tomorrow night 8). That will be a relief as the first show of the year to go to comes up next weekend.

To remove that nut and the cam chain nut or to tighten them I use a bar of aluminum about 3/16" thick and 2.225" long. I remove the cam chain adjuster nuts for some room then wedge the ends of it against the teeth of the two sprockets, one side on top of one sprocket and other side on bottom of other sprocket. You can really torque the wrench without pulling the intermediate shaft towards the front. The force goes against the chain. I also use this same method for the primary side. Placing an aluminum flat bat against the clutch sprocket teeth and the crankshaft teeth allows the removal or tightening of the nuts without placing the engine in 4th gear and holding the rear brake. Saw that in a Harley manual once and it works great.

mike,

I like the rope trick, I used that on my Harley and it worked nicely. If your valves kissed, and there are witness marks, I am afraid there is a good chance they won't seal well. If you can check for seepage with petrol, if the head is off, or if you have a leakdown tester if the head is still on it would be wise to check. Otherwise if the engine runs, you may have poor idling but it will run okay at faster RPM.
Hope this helps, I feel your pain man!

Cheers Richard

Intake valves seen opening on the upstroke? Won't start or even fire, hm, sure sounds like mine when I mis-set spark off wrong TDC on alternator mark. It only takes a few degrees off on cam to make valves and pistons clash so if turns over so I'd sure keep the error on which TDC to use in mind. Ugh, next weak link after the intermed shaft in thin case is the brittle oil pump snout.

It is possible that your intermediate spindle was loose for the same reason mine was:

I had fitted an automatic cam chain tensioner from RGM and because it held the chain so damn tight it caused the intermediate gear spindle to wear oblong.

When I had my motor rebuilt by Jim Mosher last year, he was horrified to see the spring loaded cam chain tensioner in place, and insisted that it be removed and replaced by the stock item.

Having seen the damage it did, I would never install such an item again.

Of course, maybe you are running a spring loaded chain tensioner!

In which case, never mind.

ditto on racheting or ramping spring tensioners, taboo, till something else comes along. Only takes one over tight chain event to ruin a series of weekends.