Fettling a Mark 3

G'day all, this being my first post I will start with an introduction.
Having grown up with bikes and owned the best ever 650ss at the age of 19 I've had a taste for Nortons most of my 57 years.
A few years back I had a beautiful Atlas, but alas I let her go in favour of a more reliable Guzzi. But the Norton addiction has never left and I find myself once again fettling,but this time on a mate's Commando. I'm considering it as another introduction, with the intention of getting one for myself when the time is right. My dayjob is making classical guitars.

So my mate bought this bike which hadn't been started for 3 years and hadn't been looked after too well up to the point when it was parked.
It took a few hours to work out all the wrong connections around the coils but I finally got her running. However at that stage I didn't consider it safe to give it a test run.
Instead I dismantled it down to the carcass, finding notchy bearings in the headstock and rear wheel, oil tank mountings broken, brake calipers in need of seals as they were almost seized,and cosmetic problems with the tail light assembly, sheared studs in the footpeg mount, bolts missing for tank mounting and a need for headlight mounts which were rusty and fork gaiters to cover the pits in the lower fork tubes. As well the wiring wasn't hooked up properly and the handlebar controls needed a bit of work. The clocks were askew in their cases and the speedo drive is broken.
Having seen some of the magnificent restos on this board I am almost ashamed of the approach with this bike. That is, to get it as good as possible for the least amount of money in the shortest timeframe.
But that's the agenda here and I feel that there may be others out there with a similar appraoch.
So I thought I'd document the small jobs as I do them with a view to discussion on any of it , and hopefully some help going either way.
Those of you who have done immaculate ground up restos may not wish to look further as this will be way beneath you.
Below are pics of the start of this process in no particular order.
I have stripped the triple trees with a scotchbrite pad on a drill and now sprayed them silver with enamel in a rattle can.
I also used a rattle can for the black paint on the taillight assembly. The taillight lense was broken and full of silicon, which I cleaned up with superglue debonder and glued up with superglue. I have stripped the clock holders, at first thinking to polish them but am opting for the original black of the mark3. This also has the console with the idiot lights.
Progress pics to come if anyone is interested.
Cheers,
Dan

Re: Rebuilding a Mark 3

I see a different hammer in nearly every photo...you'll fit right in here! Now if we can get you to post photos on how to build guitars while you are at it!

Russ

Re: Rebuilding a Mark 3

rvich said:

I see a different hammer in nearly every photo...you'll fit right in here! Now if we can get you to post photos on how to build guitars while you are at it!

Russ

Click to expand...

I could do that if you like as I have extensive documentation of a guitar being made.
But I thought this was sposed to be a Norton forum?
I got a few things back together on the Norton today but haven't taken the pics yet.

Here's a side in the mould:

Re: Rebuilding a Mark 3

That looks positively medevil!!! I love it!!

Re: Rebuilding a Mark 3

Alright medieval it ain't.
Here are a few more of the beginning stages.
Laying up the sides with epoxy resin

Re: Rebuilding a Mark 3

Welcome Luthier, I'm also new to the forum, and also have a '75 MKIII that I picked up on the cheap , it hasn't been run in more than 20 years though, and I really don't have that much money to spend on my bike. Growing up just outside of Houston I always had dirt bikes as a kid ( lawn mower powered go cart and mini bike, Honda Z-50 & XR-75 ,'69 Yamaha 180 2 stroke twin scrambler, '73 Yamaha 100, Suzuki 100 TS--my first street bike-- '77 Yamaha XS750 triple, '78 Honda CB750F single overhead cam motor punched out with an 828 kit, smooth bore Mikuni's, Kerker header and Comstock wheels with sticky tires. But.... back when I was 15, my older brother had a 1970 Norton 750 "S" with a beatiful deep blue metallic paint job, halo headlight ring, hooker header, 1 up and 3 down and miles and miles of that wonderful cast aluminum. Well I wanted to ride it so bad, but my Pops wouldn't let me at first. I just never gave up and finally he gave in and said I could ride it but he was gonna ride with me using my Suzuki 100. Well we wern't even out of the subdivision when I went around a left hand corner and cracked the throttle open, the back end broke loose and now I'm doing a perfect power slide thinking Holy s**t I'm gonna wreck my brothers bike.... but I let off on the gas just a little bit & she hooked up, straightened up and I opened it up!! Boy that stayed with me all these years, so even though I really didn't have the money or the time for my Norton, here I am at 48 with 6 little kids of my own, (making me pull MY hair out). But you know what ...that 850 in my garage really takes my troubles away. Will be following your posts with great interest. Cj

Re: Rebuilding a Mark 3

I don't know how much general interest there might be in the guitars. But I for one appreciate getting a look at the process.
Thanks!

Now regarding that MkIII...keep up the good work.

Russ

Re: Rebuilding a Mark 3

rvich said:

I don't know how much general interest there might be in the guitars. But I for one appreciate getting a look at the process.
Thanks!

Now regarding that MkIII...keep up the good work.

Russ

Click to expand...

Quite right Russ, we're here for Norton things. If people want I can start a separate thread about geetars, but this one's about the Mk3.
CJ and others who want to get this job done cheap and quick, I just should say that it all depends on what you start with, of course.
This bike was shabby in certain areas that would have cost a fair bit if you paid mechanics wages to do it, but there are a lot of good bits and the motor seems to go very well. Haven't yet tested the gearbox or investigated the clutch or primary, but first to get it all together.
I fitted new head bearings and sprayed the triple trees silver, fitted the rubber gaiters, waiting for the new headlight brackets to assemble forks, and polished left side footpeg hanger. I was careful to remove and clean where the diode goes, and refit with conductive grease.
I stripped and resprayed the clock holders black. I removed the oil tank as it was flogging about due to a missing lower bolt, but I felt it all needed a good clean anyway. I removed a lot of electrical tape, exposing some nasty wiring. So today I invested in a few diameters of heatshrink, some extra expensive connectors, some good quality auto wire, some spiral cable wrap and some high temp expensive electrical tape, plus some cable ties.
Will begin by soldering and shrink wrapping all odd joins in loom and later doing a bit of precision wrapping , after testing and tracing.
Here are the snaps I took this morning.

Re: Rebuilding a Mark 3

Looking good, which steering head bearings did you use?

Re: Rebuilding a Mark 3

cjandme said:

Looking good, which steering head bearings did you use?

Click to expand...

Not sure, NTK I think, just basic 6205's.
I took the right footpeg hanger off to clean and got it back on today.
Cleaned up a lot of the main wiring loom, using inline soldered wires covered in shrink wrap. I discovered a few wires that must have got hot at some stage so I traced them through and fully replaced them.
I found some obsolete electronic things mounted under the coil bracket so I took them out and fitted the boyer brainbox up in there, wrapped in foam and held tight with cable ties.
I wrapped everything back up with a high quality black tape and fixed the loom in place with more ties.
Then I oened the chaincase to have a look. I was sorry I did, because everything looks pretty immaculate in there and all I succeeded in doing was to ruin the gasket.
Here's a question : should the chaincase gasket be thoroughly glued on with gorilla snot, or is it possible to get a seal by simply using the gasket?
And another question : the chain tensioners in the primary case on the Mk3 appear to be spring loaded and non adjustable.
Is that so or is there some adjustment possible or necessary?

I've been made aware that the starter clutch/pawl thingo is a possible worry as if it locks up it can throw you down the road.
Any advise about this would be great. It doesn't look too easy to de-commission the starter mechanism.

It's the most amazing primary I've seen, being a triplex chain and the clutch looks a bit like a car one. It all looks pretty 'out there'.
I think I prefer a simpler setup. Anyway I think I will probably just put the cover back on and give it some 10 weight oil and forget about it.
If it were mine I'd be thinking seriously about a belt drive.

Re: Rebuilding a Mark 3

luthier said:

Here's a question : should the chaincase gasket be thoroughly glued on with gorilla snot, or is it possible to get a seal by simply using the gasket?

Click to expand...

A (greased) MkIII gasket should make a completely oil-tight seal, additional sealants should not be necessary-unlike the earlier models which have a "rubber band" seal.

luthier said:

And another question : the chain tensioners in the primary case on the Mk3 appear to be spring loaded and non adjustable.
Is that so or is there some adjustment possible or necessary?

Click to expand...

The MkIII tensioner is hydraulic and automatic (once the system has filled with oil), the springs are there to provide initial chain tension until the unit is primed (primary oil drops off the upper chain run into the "hopper" on the tensoner once the engine has started).

luthier said:

I've been made aware that the starter clutch/pawl thingo is a possible worry as if it locks up it can throw you down the road.
Any advise about this would be great. It doesn't look too easy to de-commission the starter mechanism.

Click to expand...

The starter sprag clutch can break but I've never heard of it throwing anyone down the road? Perhaps you are confusing it with the gearbox layshaft drive-side ball bearing which can do that and should be replaced with the roller bearing conversion or FAG 6203TB phenolic cage ball bearing.

luthier said:

I think I prefer a simpler setup. Anyway I think I will probably just put the cover back on and give it some 10 weight oil and forget about it.

Click to expand...

You may find that "10 weight" oil (or ATF) is too light for the MkIII hydraulic tensioner? I recommend you keep to the factory specified 20w/50 engine oil in the MkIII primary case.

That's excellent L.A.B.
Thankyou very much for that info.
Do you know what quantity of 20/50 should go in the MK3 primary?
Cheers.

luthier said:

Do you know what quantity of 20/50 should go in the MK3 primary?

Click to expand...

Remove the chromed slot head screw (B) and fill to the hole.

http://britmoto.com/manuals/Manuals/850_man.pdf - Routine Maintenance, Section K9.

http://britmoto.com/manuals/Manuals/Riders_4.pdf - p. 10 (pdf p.9)

Alternatively (or if you experience any clutch slip?) fill with 200cc.

Thanks again L.A.B.
I am attempting to fit the headlight and front indicators as the indicators and new ears came in the post yesterday.
I couldn't download that PDF link that you posted, so I'm in the dark about the correct fitment of the above items.
I think the problem must be that the headlight I have is not a proper Commando one, because it appears that the indicator stalk should go through the headlight ears, through an offset spacer and into the headlight which should have the right thread inserted there.
Is this a correct assumption? Because the headlight I have has a much smaller mounting hole and the old ears were pretty butchered.
I am therefore proposing to drill out the headlight shell to accomodate the indicator stalk, make up a couple of spacers with one side cut on an angle, and fit using some tidy washers and an internal nut to secure it on each side.
Would this seem a reasonable fix without going to the expense of a new headlight?
Thanks for all the help.

Good to see another commando getting sorted out for some road work!

Its funny a few years ago (OK many years ago) I would have been horrified at the thought of buying a bike and totally stripping it to rebuild it better than new. I always like to do "rolling" resto's , these things are meant to be used not just be garage pieces.

Some people though do an excellent job of the nut and bolt rebuild and although I love the finished product its not for me, good to see the pics of your rolling resto! Keep up the good work.

luthier said:

I think the problem must be that the headlight I have is not a proper Commando one, because it appears that the indicator stalk should go through the headlight ears, through an offset spacer and into the headlight which should have the right thread inserted there.
Is this a correct assumption? Because the headlight I have has a much smaller mounting hole and the old ears were pretty butchered.

Click to expand...

I don't think I can see the riveted-in Mk3 flasher relay clip in the 4th photo of your 1st message, so the shell may not be the original Mk3 item?
Yes, the headlight shell mounting holes should at least be large enough to take the flasher stems, with the 06-6547 spacer between the bracket and the shell on each side (see photo below and item [26] on the Old Britts diagram & list) with a self locking nut and washer inside (some Lucas shells have captive nuts).


The Old Britts diagram shows bolts [24] retaining the headlamp, but they are obviously incorrect.

http://www.oldbritts.com/nor_mk3_75_32.html
http://www.oldbritts.com/image/1975_g32.jpg

luthier said:

I am therefore proposing to drill out the headlight shell to accomodate the indicator stalk, make up a couple of spacers with one side cut on an angle, and fit using some tidy washers and an internal nut to secure it on each side.
Would this seem a reasonable fix without going to the expense of a new headlight?

Click to expand...

I can't see any reason why you'd need to angle-cut the spacer/s? With the correct width spacers in position, the headlamp bracket "ears" should be approximately parallel with each other so the spacers are square-ended. Note that there should be 2 O-rings [46] between the lower yoke and the headlamp bracket plus another O-ring between the top of the bracket and the upper yoke (top O-ring drawn-in not numbered, but note list 99-0502 O-ring total is 6 pieces).

http://www.oldbritts.com/image/1975_g21.jpg

http://www.oldbritts.com/nor_mk3_75_21.html

It's not too difficult to get the headlamp brackets mixed up-as they are similar-but not identical, the triangular slotted plates are not symmetrical, occasionally you see Commandos where the brackets have been mounted on the wrong side-so the adjustment slots are angled and not parallel with the ground as they should be.

Thanks again for your help L.A.B.
I've made quite a lot of progress over the last week. I now have the majority of the wiring sorted with just the wires to the tail light and rear indicators left to extend and fit new connectors and heatshrink wrap. Basically I'm waiting on some nuts to fit the rear indicators and a new speedo drive to refit the back wheel. I ended up reusing the main rear wheel bearing as it was bigger than the ones I was sent and when washed and repacked it was smooth and I can't feel any play. The front wheel bearings are OK.
I've bled the front brake although it feels a tad low. I think it may need new pads but I'm sure it will work well with the new seals and the cleanout.
There were two mystery wires in the headlight shell, a red one that isn't connected to earth and a white one.Neither seems to get any power to it so I just left them alone. But everything is working except the starter motor which I am going to forget about and leave for the future. Also until I get her fired up I obviously can't check the charging situation. All lights work[except for the neutral idiot light which has a broken light holder] and we have spark.
Here are some photos of where it's up to.
I have run all the alloy that I took off over a buffing wheel which although it's not mirror finish is a big improvement.
The wiring had got hot at some stage and the repairs were unsatisfactory. I soldered three lengths inline for the offending wires and heatshrink wrapped them, before re-wrapping the loom. There was also a red wire from battery to frame that was pretty melted so it was replaced.
In the headlight shell I replaced all the bullet connectors with expensive 240volt rated tag connectors which are double crimped, and fitted heatshrink over them all.