The Commando that came in from the Cold.

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I wass told you have the last .10 over so went with it for rebore. Seemed the real prob was valves.
 
Well, depending if what I've been told about the history of the bike is true or not, then I believe I will have to replace the exhaust valves at least, and possibly more in the head. I can't say much more about the status of the engine until I have it apart. Except that is seems to move very free now, and there remains penetrating oil on top of the pistons after over a week of having been sitting in the chambers. Doesn't necessarily mean anything, but at least possibly that the rings and sleeves didn't become one on an irreparable scale.

I was told years ago, that one or both of the exhaust valves were burned from running too lean due to the higher flow Dunstall muffler, and insufficient jetting to richen up the mix. Again, the is speculation based on a conversation I had years ago. The truth will come out when the thing comes apart. :wink:

Hopefully get some time soon to get the engine apart, out of the frame and on my workbench to have a closer look.

Cheers all, and Merry Christmas!

Jon
 
Well, a quick update at least. Work progresses, if slowly, tho I haven't even reached the 'spending big money' stage, at which point it will probably move a LOT slower. =)

In any event, another member graciously offered to come by and give a hand with the initial stage of disassembly, and bring with him a number of the critical tools which I do net yet have. (Engine sprocket puller, Whitworth/BCS wrenches, rocker spindle puller, etc....) I suppose many of these will end up on the to purchase list down the road. More importantly, it was a lovely gesture and volunteering of time which helped me to started and past the point where I couldn't do anything for lack of the correct tools. On to the cleaning, assessment and parts collection stage for the motor.

Anyway, I don't know how bad this is, in comparison, but the inside looked a little gnarly to me:

Didn't look promising...
The Commando that came in from the Cold.

The Commando that came in from the Cold.


Nor the heads...
The Commando that came in from the Cold.


But, on the whole, not so bad I think?

The Commando that came in from the Cold.


The Commando that came in from the Cold.


Another plus. Cam, cam followers, pushrods and rockers all seem to be in good kip, without any play in places where it seems there ought not to be. Shouldn't be any need to renew any of these bits. I am working on getting decent shot of the cylinder bores, but lighting/flash/glare aren't cooperating with me, and I dare not bring my SLR into the shop, but I will update soon with more snaps. Pistons are also in good shape, and possibly reusable, but some VERY slight pitting in the bores still suggests to me that a honing won't be enough to produce a good surface for ring seating. Might need to bore out to the +10 thou piston size. (Which leads to further questions about head gasket thickeness etc... down the road, as they are apparently racing pistons, and taller than standard size. How much play room is there on these engines before you encounter interference?)

As I said, more photos will come. I am learning more about this old beast every day, and am getting more intrigued all the time. Aside from the rather mundane frustrations like not seeming to have the right size wrench for anything, when I finally thought I had bought my last wrench set. :shock: Having a brief moment of utter confustion where seeing there were no valve seals on the exhaust side, wondering how anyone could have possibly not installed them on a rebuild or such, followed by complete astonishment upon realizing that none are spec'd for the engine at all. How much oil do these things consume over time anyway? :mrgreen:

Anyro, I will have a couple of days early next week to do nothing but tinker along, do a little more dissasembly, clean parts, and begin the dread list of things I will need to purchase to to a rebuild. Nevermind the trip to the machinist. I never did think this was going to be easy or quick, and I am seeing that I was probly right. (Oh, yeah, and everyone else here who chimed in.) From what I am seeing and learning as I go, this is going to be much less of a challenge in the sense of the bike being mechanically difficult to work on, but a patience game played against the eccentricities of the old girl, countless hours cleaning and the costs of renewing those parts which must go on to the final scrapyard. =)

Cheers!
Jon
 
Ugh all the crud in the head is one reason not to turn engine before cleaned up. They used to sell .010" over pistons/ring sets but very hard to impossible to find currently so should raise your bore expectation$ in .020" amounts. Taking on Commando w/o 3 sets of tools SAE, METRIC & Whitworth is like jumping into sewer creek w/o paddles. Its takes a global village and a bank to rasie a Commando child to fully fettered road worthy.
 
It's difficult to tell from your photos. The dimension from the top ring to the crown of the piston seems larger than what I've just measured on my old standard 750 pistons. (0.222" on one 0.227" on the other.) If they came from Gus Khun and they are taller than that I'd say they were high compression, probably 10:1
 
You be surprised at how that head will clean up, pull it all apart replace the guides and check to see if the valves are sealing, then go from there, if the cam and lifters are still good then the valves could be as well, who knows untill you pull them out and see how the seats are, I have had my head rebuilt 2 times now and ported out and I am still running the orginal valves and seats with a lot of miles on them.

Ashley
 
Just another quick update as a little more work goes on. Who doesn't like photos? At very least, I am appreciating all the sharp eyes out there who are clueing me into things I may well have not noticed otherways. My continued thanks to you all.

It's difficult to tell from your photos. The dimension from the top ring to the crown of the piston seems larger than what I've just measured on my old standard 750 pistons. (0.222" on one 0.227" on the other.) If they came from Gus Khun and they are taller than that I'd say they were high compression, probably 10:1
Click to expand...

Good eyes, and yes the replacement pistons are a tad taller than the STD ones that were in there. Originals are ~30.6mm from the top edge of the wrist pin hole to the top of the piston, and the +0.010 over pistons are 31.2mm on the same measurement, and are also slightly domed, so I would think they would bump the compression a little. Any problems running 10:1 compression pistons on the stock cam? I will already be stuck running high octane with the fibreglass tank as mentioned before, but aside from that? An electronic ignition is in the plans, so at least I shouldn't have to worry about timing advance. All that said, if my machinist reckons the bores are okay with just cleaning/honing, and new rings, I will save the overbore pistons for the next required teardown.

Actually, that said, the pistons look to be fine. Except where idiot me let on of them fall onto a stud and get a little marred on the skirt. Nothing that can't be smoothed with a little wet sanding, but still a "doh!" moment. :roll:

After some preliminary cleaning, the heads look okay. Nothing that stands out to me as critically wrong.

The Commando that came in from the Cold.


The Commando that came in from the Cold.


Valves seat look like there is lots of meat left, and to my non Norton experienced eyes, haven't been cut so far back that sunken valves are an issue. Intake valves may get by with just a good cleaning, cutting and grind. Exhaust valves however, are trashed, and will require renewal, I should think.

The Commando that came in from the Cold.


The Commando that came in from the Cold.


Getting more intrigued with every day spent tinkering. Didn't do much today, but spend hours a few hours cleaning parts, organizing the shop and pondering this old girls past.

Now, when the Canadian Dollar isn't in such bad shape, I may actually buy more of the required tools soon. :shock:

Cheers!
Jon
 
KzJonny said:
Having a brief moment of utter confustion where seeing there were no valve seals on the exhaust side, wondering how anyone could have possibly not installed them on a rebuild or such, followed by complete astonishment upon realizing that none are spec'd for the engine at all. How much oil do these things consume over time anyway? :mrgreen:
Click to expand...

Keep in mind that the exhaust valve stem has exhaust pressure against it except during times of closed-throttle decelerating (how often do Nortons slow down?) so is always getting its oil pushed back up into the head. Add the hot exhaust gas rushing past the exposed stem every time the valve is open. You get the idea...

On the other hand, intake valves are almost always under some level of vacuum that's trying to suck oil past the stem, so need all the seal they can get. It would appear that's what was happening here:
KzJonny said:
The Commando that came in from the Cold.
Click to expand...

All-in-all, nothing looks too scary so far! It's good to know the cam and followers look good.

Nathan
 
Keep in mind that the exhaust valve stem has exhaust pressure against it except during times of closed-throttle decelerating (how often do Nortons slow down?) so is always getting its oil pushed back up into the head. Add the hot exhaust gas rushing past the exposed stem every time the valve is open. You get the idea...
Click to expand...

Yup, good point. I suppose I wasn't really thinking too much about the positive pressure generally being exerted against the exhaust valves, but certainly at shut down, there much be some amount of oil that would run down the valves? In any case, it is what it is, and these motors clearly work as intended, so there you have it. If perhaps with a little higher oil consumption than what I am used to, but I suppose it will depend from engine to engine, and I will find out when I get mine back together. (Comnoz breather is going to be on the list of probable upgrades as I have the correct frame for the plug style one, and the cam timed crank breather system....)

These guys are just north of London Ont. They have Whitworth tools on sale now. http://www.walridge.com/
Click to expand...

Yes again, and thanks. I will see about ordering some up some bits and tools from them before the month is out. I did just pay for my round trip for my annual work holiday in NZ, so available fund are at a bit of a low point. Still, there is some good stuff there at nice prices that I may well need during the summer rebuilding months, so I will have a second and third look and think about what I may pick up!


As a last note, having the rings off the old pistons, I can see they are in fact the early slotted comma type ones. Now, I will still see what my machinist has to say about the condition of the bores, and whether or not they need anything more than a hone job before reassembly, but I suspect they will need a slight bore. Everything I have read suggests that the slotted pistons are actually not so bad provided you stay out of the 7K RPM zone, and ride fairly normally. This will probly be the case for me with this bike, but I also don't want to go through all the effort of rebulding the engine just to have the pistons fail on me, and necessitate more work. So.... the +0.010 overbore ones will probably get used. That said, I had a closer peek at them, and they definitely Hepolite pistons, and cast with 13232A on the inside, as well as the AE symbol. On the crowns they are stamped with '18590', +0.010 and 'ID. 12'.
The taller domed top suggests high compression pistons, but I wonder if anyone out there is familiar with these particular ones and what they might do to compression ratio etc.... There are definitely much more deeps recessed cutouts for the valves, so I figure interference shouldn't be a problem with a direct swap? But I supposed a dry run on assembly will be in order in any case. The head gasket I have is copper and i believe intended for lower compression engine use.

This lead to a couple more questions: Does the copper gasket need to be annealed before use? Would it be suitable for use with a higher compression ratio?

My instincts are that if there is not interference, and if everything is torqued correctly, then the gasket material isn't terribly important as long as it seals well, and these are genuine NOS Norton stuff, so should be fine. But, as with so many other things Norton, I am a beginner, and hoping to avoid a major blunder by making assumptions based on my past experience with Japanese bikes. So, advice is, as always, greatly appreciated.

Cheers!
Jon
 
The last time I had my barrels off I put a new copper head gasket on and nomaly I would annealed it but I forgot to do it, well it been on for 5 years now and have only retension the head once in that time, have done 24,000 miles since and the head isn't leaking, but I did spray Halmor gasket guey on it before putting it on.

Ashley
 
Your doing a nice job.

You know personally I would probably go for the better pistons myself. It would be shame to have a problem after your work. :oops:

If you are worried about compression you can put a thicker gasket under the barrel. I think Jim Schmidt has them

http://www.jsmotorsport.com/technical_compression.asp

Check the push rod lenghts if you do.

I use copper head gaskets on my race bike. I always anneal it and check for a very good fit.

I use copper coat and do two cycles of run, cool overnight and then retorque.
 
Just a quick update, and I suppose a bit of a bump to the post.

Considering much advice from others here on the forum, Norton owners I've come across locally, and having a good long chat with Rick Hallett at Highway Cycle just up the road from me, I've made a few decisions, and spent piles of money. (Okay, maybe not piles, but it's a good start, and I expect more to dissapear along the way.....)

The plan as it stands right now, is something like this.

-Old comma type piston are going away. Turns out the bores were only about a half thou out from standard, which Rick considers perfectly acceptable, so I have a new set of standard size pistons on the way. (This means that this higher compression +.010 pistons are going to be sold off to whoever has a use for them, I have decided to stick with stock compression as this will be a weekend bike, not a racer....)
-Valve seats have been cut and ground to new Kibblewhite valves.
-Bores got a quick hone and crosshatching
-New top and bottom end gasket kit
-handful of other parts, superblend mains, new crank bearing shells etc...

Still haven't got the bottom end apart, as I am reluctant to put enough force on the camshaft end nut without a cutaway timing cover or similar. That will probably come off when I go the shop to pick up parts, and have a look at the rebuilt head.

Photos to come when I pick the stuff up. Just wanted to say thanks to those who've helped so far, and the many, many others for just having a site like this where I can cruise around and almost always find some answers or solutions to problems without even having to ask.

This project is going slowly which I expected, but isn't done, so no worry there. One day, this Norton will run again.

Cheers All!
Jon
 
In the past I have used an impact on the cam nut, works wonders. But, you may be right in using a cut away timing cover to support the shafts.
Good luck with your project and don't forget to clean out the sludge trap in the crankshaft.
John in Texas
 
Whoo!

I have been away from both my Norton and this post for a very very long time. Since my last posting in this thread I have moved across the country, worked for a bit, moved back across the country to a new job, then to another. One day I may settle down, but I am not holding my breath. I am, however, for the moment back in same city as the Norton was stored this whole time, and once again have a warm, dry, indoor place to work on it, and have started slowly to do so. Towards the end of the fall, I finished most of the gross dissasembly, and have the large component chunks of the bike apart, carefully labelled and bagged, and ready for assesment and refurbing/cleaning a section at a time.

In responce to john robert bould: sorry for the delay, that is in fact some kind of orangy bedding in material on the rings. After decades in storage, I hesistate to call it a paste, but more like a coating at this point. In any case, it is not rust. All things considered, those pistons are in very good shape. I am curious to know if anyone here has any clue as to their value, or perhaps what I should be asking when I get around to selling them. I bet they are hens teeth at this point, but don't want to be silly about what I am trying to get for them.

Coming right out the gates, I have a couple of questions that apply to problems immediately in front of me. In onder to finish taking the frame apart, I neet to dissasemble the rear isolastics and remove the through bolt to get the swingy to come off. The instructions in my Hayes manual are clear like mud on how to accomplish that, and it's pretty obious that he bolt does not just come right through and allow removal as easily as that. I will look around for other instrutions again, but any quick methods, or advice on how to accomplish it would be very much appreciated.
Following on about the isolastics; I am going to assume I will need new ones, since all of the other rubber stuff on the bike was pretty much garbage after decades of sitting around, and I have been reading unpleasant things about vibrations and frames snapping if these aren't properly dealth with. I seem to have found that my options are something like the following
- replace the current iso's with the same stuff, and the same difficult to deal with shimming system, which appears to be despised, and generally not the best course of action
- replace with MK3 type vernier adjustable type isos. more expensive, but easier to adjust
- get new guts, and special oder in the mick hemmings type verniers, which use stock pre-mk3 everything else

Any thoughts? Are the Hemmings ones even still orderable, or should I maybe get on the horn to him myself and find out? I had a thought that perhaps someone in England might have a better idea on that one. Also, are the MK3 isos and their adjustors compatable with the early type mounting brackets, or would I need to replace all the hardware to use them. That part wasn't super clear either.

Next point I wanted to ask after, although I think I already know the answer to this once. Question about wheel bearings. I have some new ones I ordered in not so long ago, and on recieving them, (purchased as wheel bearings mind.) they had a stick on the package reading 'SUPERBLENDS - NOT WHEEL BEARINGS' ... Okay, I double checked the listings, and it seems they are doube listed as layshaft bearings and wheel bearings. Apparently the same size, only very different tolerances. These ones are NJ203E type, and were ~$35 each. Great quality bearings FAG, the whole nine. However, I am thinking that the $6.00/per 6023 2rs bearing of the same size from my local fastener supplier will probably suffice for wheel bearings? They have sufficient load bearing rating and are 20K rpm, so I am thinking I can save $100, and return the others? Save me from getting bearings that will fail in the intended purpose, but I don't remember ever paying much more than $8-10 for motorcycyle wheel bearings....

Thanks for any help I can get with this as a start. I will have plenty of photos coming along soon, and LOTS more questions. I am hoping to get the frame and swingy cleaned up and asessed pretty soon, and have some questions for the experts here regarding that. As well as probably having a go a putting the engine back together as my workbench project over the next couple of months. So, if anyone read this far, I appreciate any advice and help as always.

Have a good weekend all.

Cheers,
Jon
 
KzJonny said:
In responce to john robert bould:
Click to expand...

Sadly, John is no longer with us.


KzJonny said:
Coming right out the gates, I have a couple of questions that apply to problems immediately in front of me. In onder to finish taking the frame apart, I neet to dissasemble the rear isolastics and remove the through bolt to get the swingy to come off. The instructions in my Hayes manual are clear like mud on how to accomplish that, and it's pretty obious that he bolt does not just come right through and allow removal as easily as that.
Click to expand...

If, by "bolt" you mean the rear Isolastic stud, then theoretically, it should pull/push out, however, it can seize due to corrosion which makes it more difficult to remove.

Here's the factory manual, this is more useful than Haynes;
http://www.classicbike.biz/Norton/Repai ... mmando.pdf



KzJonny said:
I seem to have found that my options are something like the following
- replace the current iso's with the same stuff, and the same difficult to deal with shimming system, which appears to be despised, and generally not the best course of action
- replace with MK3 type vernier adjustable type isos. more expensive, but easier to adjust
- get new guts, and special oder in the mick hemmings type verniers, which use stock pre-mk3 everything else

Any thoughts? Are the Hemmings ones even still orderable, or should I maybe get on the horn to him myself and find out? I had a thought that perhaps someone in England might have a better idea on that one. Also, are the MK3 isos and their adjustors compatable with the early type mounting brackets, or would I need to replace all the hardware to use them. That part wasn't super clear either.
Click to expand...


Although Mick Hemmings has closed his shop now, he is still trading.
There are three types of vernier adjuster. The Mk3 vernier parts, (requires modification of the front Iso mounting) also the 'Hemmings' kit and another (no name) conversion kit for pre-Mk3 models that use the pre-Mk3 Iso parts (and do not require the front mount modification).


KzJonny said:
Next point I wanted to ask after, although I think I already know the answer to this once. Question about wheel bearings. I have some new ones I ordered in not so long ago, and on recieving them, (purchased as wheel bearings mind.) they had a stick on the package reading 'SUPERBLENDS - NOT WHEEL BEARINGS' ... Okay, I double checked the listings, and it seems they are doube listed as layshaft bearings and wheel bearings. Apparently the same size, only very different tolerances. These ones are NJ203E type, and were ~$35 each.
Click to expand...

Yes, the NJ203E is the layshaft 'Superblend' roller upgrade, part 06-7710.

The 6203 ball bearing was both wheel bearing and the original layshaft bearing and why they had the same part number 04-0100.
If you were sent NJ203E bearings as wheel bearings under part 04-0100 that was a mistake.
 
As far as the vernier adjusters, I got the Hemmings ones for my 69/70 S bike and they work great. Use your standard items, they work with any system with no machining or adjustments other than the verniers themselves. As LAB says, the rear iso stud can get 'stuck' and may need persuasion getting out. But don't beat up the threads. Nice to see you back.
 
" If you were sent NJ203E bearings as wheel bearings under part 04-0100 that was a mistake. "
But I wd recommend keeping at least one of these, for use as the layshaft bearing (unless it has already been replaced), which is a "nortonious" :) weak spot in the transmission.
 
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