New project advice requested

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Greetings all,

I am a newbie to this forum and Nortons. I have acquired a '75 Mark 3 with 2900 miles on the odometer that has not run for over 25+ yrs. However, the amount of grease and filth on the bike led me to question that number. Now looking at the internals, I believe it is likely accurate.

My two choices were to do some minimum maintenance and get her running or go a little deeper. We have now passed that point:

New project advice requested


I am now seeking advice at how far down the rabbit hole I should progress. My wish is to get a very nice looking bike, although not a show winner, that is as reliable as a British machine can be. Since I have it torn down this far I want to tackle anything that can be a known problem at this time. I have scoured this site and below is my checklist with questioned areas. I am looking for some feedback in this area and also anything I missed.

1. Engine top end....If bore is within limits, I was just going to clean up, repaint and maybe new rings. QUESTION: Is there any huge advantage to new black diamond valves vs stock @ 2900 miles??

2. Engine Lower end... I have concerns about the soft cam issue. How would you proceed? I have not split the cases but do have the top end off and cam wear doesn't look excessive but it shouldn't yet. I don't want to be back in here in 5000 miles if I can do it now. What is the best choice for a street machine and what else then needs replacing? I know I am opening a can of worms with this one. Also bearings -- did the mk3 come stock with superblends?

3. Gearbox .... Layshaft bearing a must....general inspection...maybe bushes??

4. Brake system...rebuild all calipers/mc and stainless lines. Probably no rebore until I see what I need (Currently riding a Guzzi with all drums)

5. Bought a Tri-Spark EI to fit.

6. Probably going to rebuild Amals.

7. How to inspect swingarm?? General tightness?? Probably drizzle some 140 wt oil in the top bolts with syringe.

8. New rubbers needed for isos ???

9. Dyno Dave starter (orig FULL of rust), batt cables, and clutch seal

10. New wiring harness ??? I am skeptical of 40 yr old wires.

11. Any rubber anything I encounter.

12. Polish everything shiny.

13. Ride it for a year, work the bugs out, and then hit Brent up for a new paint job and a fit a Corbin seat.

I have really enjoyed the many hours lurking around this site....what a resource and great group of users. I have owned this bike for five years and it's sat idle (too many other projects and job change.) This is my winter to do it.

Thanks in advance for your time and advice.

Best regards,

Doug Beck
Minneapolis, MN
 
Treetopflyer said:
1. Engine top end....If bore is within limits, I was just going to clean up, repaint and maybe new rings. QUESTION: Is there any huge advantage to new black diamond valves vs stock @ 2900 miles??
No

Treetopflyer said:
2. Engine Lower end... Also bearings -- did the mk3 come stock with superblends?
Yes

Treetopflyer said:
3. Gearbox .... Layshaft bearing a must....general inspection...maybe bushes??
Check bearing.

Treetopflyer said:
4. Brake system...rebuild all calipers/mc and stainless lines. Probably no rebore until I see what I need (Currently riding a Guzzi with all drums)
Sleeve Master Cylinder.

Treetopflyer said:
5. Bought a Tri-Spark EI to fit.
Good

Treetopflyer said:
6. Probably going to rebuild Amals.
New slides, the anodized ones.

Treetopflyer said:
7. How to inspect swingarm?? General tightness?? Probably drizzle some 140 wt oil in the top bolts with syringe.
MkIII swingarms are pretty good. I'd leave it alone aside from a little oil.

Treetopflyer said:
8. New rubbers needed for isos ???
Maybe, get it running and see if they have flat-sidered from sitting so long.
 
Great find. You have a clean, low mileage machine.

As for a cam choice, it depends on what you want. I am using a megacycle 560 cam in my fastback and I miss the smooth idle of the stock grind.

This is a great time to renew wiring, go to negative ground, LED lighting and a good dose of reliability. Take a look at the Eastern Beaver site for some relays and plug and play wiring parts. Pulling the swing arm to inspect, add quad "O" rings might be a good idea. You have the latest :wink: and greatest swing arm set up.

Check out the CNW site to the OldBritts site for starter options.

Give the engine, gearbox and isolastics the full treatment while you have it down. How much money do you have in your "secret" project account?

Mike
 
I can see you have a great project here with super low mileage so I would say do this : After 25 years or more sitting around all greases and oils will need refreshening ,wheel bearings,speedo drive,cables etc. Also seals like crankshaft drive,forks etc.will be replaced or they will fail probably on the first ride out. Roller layshaft bearing. Yes to the camfix ,do not toss the old one it will be a "core" for better harder lobes. Valves will do fine .New valve seals though.The rubber under the oil tank will be hard as rock,put in a big one or a dense foam pad support.A big gel type battery with big gauge cables to ground/power new starter .Brake lines,seals that are that old need replacing anyways so yes to braided upgrade.But do consider the 13mm upgrade too.Mikesxs.com sells a great breather that fits in just before the oil tank and is only $ 17. Critically inspect those tires then ship them to Hobot for more burnout videos. I'll bet the wiring is all still good and uesable but the connectors need inspecting or replacing.The new ignition was a good idea to prevent kickback damage to fragile sprag clutch unit.Load up that credit card and get to it,good luck.
 
Welcome to the forum.

I wouldn't buy a new harness. If the original harness is uncut and hasn't been melted, I would unwrap it a section at a time and inspect it. Then wrap with new flexible tape. Usually the harness seems old and brittle because the tape is old and brittle. I have found the original wire to be pretty good quality. It is the connectors that cause the most trouble, so buy new connectors or make your own. The Tri Spark allows you to eliminate the ballast resistor and condensor pack. So already you will have some wire you don't need. Think about what upgrades you plan to do to the charging system and so forth. If you map this out a bit you can figure out if the original harness is up to the task and what wires you don't need so that you can strip them out while you are putting new tape on it. During this process you may decide you would rather make a custom harness, or alter the original to suit.

It is gonna be a lot easier to drive out the isolastics now for inspection than do it after you have the bike back together. If the rubbers are in good shape with lots of bounce you may decide to just put them back in. Same story for the swingarm. It won't be easier to take apart once you have the bike assembled. Might as well tear it down so you know what it looks like in there. The freeze plugs come out pretty easily and are cheap to replace. If everything in there is in good shape, just reuse it.

Enjoy.

Russ
 
Wow, has original Avon GP tires...replace those. With the exceptions of known weaknesses, the orginal parts are typically better than replacement parts.
Not all 850 camshafts were soft. I'd leave the lower end as assembled by the factory with such low miles.
What was the reason for dismantling the head?
If this is an interstate, I'd be tempted to go with a single carb. Roadster, keep the amals or go to flatslides (later by others opinion as my '72 750 combat roadster does quite nicely with sleeved amals).
 
illf8ed said:
With the exceptions of known weaknesses, the orginal parts are typically better than replacement parts.

Interesting statement.

You must be talking about non-Andover parts?
 
I'll use any tire that fits and has most its center rubber still on cracked and hard no issue but to ride racer like. THE Gravel commutes grind em down too fast to make sense buying new but for sure new tires MUST be put on both ends to really be able to dial in the isolastics and not confuse with tire feed back.

You will get just about as much or better brake action just removing the factory restriction with a glowing red hot 6 penny nail than 13 mm resleeve. But the steel piston and steel caliper pucks can rust and pit Al bores so resleeve is only way to save it. Sand down rotor and pads to new surface plus a new hose and be careful how much you squeeze on them to lock up tire under 60 mph, above that its ABS like. Keep eye on master cylinder level till you KNOW its not leaking out unknown on the fly. There is NO warning before NO brake at all.

Cam can be nitrided and polished by Geoff Collins of Offset Cranks.

Starter drops voltage to electro brain sparkers so make sure yours is tested for that on E-starts. Dyno Dave has a powerful kit for year now. Get a supply of srag thingys spares - the reports here say they last about an oil change or less.

Check the spokes tension and rim centering. Ride a bit on low aired tires to both get safety sense on slow leak unnoticed till reversed control action on sudden tube blow outs and 2nd to get sense of hinged handling accelerating in long sweepers just fine until suddenly IT AIN"T!

Stock swing arm oil must be constantly renewed or else rusts up then wears and taps the spindle so some mess is innate from factory set up. Yours may already be too late for rust but at least not the wear.

Adustable iso's are nice but old rubber may work better than new, just flip the set sag distortion or bevel the rim narrow on new ones in front. Put the extra 2
old large cushions in the rear mount.

Lucas bullets are the peak of compact connectors design but metal oxidize to crumble so expect a hand full to replace.

Don't over torque to listed levels the rear dumb axle or the main shaft chain sprocket. Over torque beyond listed level the head and cylinder and case fasteners. This takes a few times as the goop and gaskets crush with heat cycles and vibes. Hylomar is my one goop for all reasons now.

Search the mods for kick lever fixing if E-start has low battery.
 
Nearly all what these guys have said. I'd go a CNW single coil conversion to go with the Tri-Spark and with NGK Iridium plugs your ignition will be top notch. Avon Roadrider tyres on your standard rims are a big improvement. Good find.
 
swooshdave said:
illf8ed said:
With the exceptions of known weaknesses, the orginal parts are typically better than replacement parts.

Interesting statement.

You must be talking about non-Andover parts?

Dave,

I quite following that string :)
 
Any Boggie men , goobbers , or dried up snot in the Crankcases ? ?? ?

Doesnt look like it was sored outdoors , In someones air co=ed neucear fall out shelter ? ?
Pulling the Timeing cover , if theres ANY Black Grot , white oxidation , red backs or tarantulars ,
Id split the cases .

Getting New Genu Wine Rod Bolts & Nuts ( N O S ) as a preliminary to splitting the crank ,and crank nuts . ( & Loctite )

Gearbox is the same .

As you say , you dont want to do it again in 5.000 miles . Wich if you were would be expensive . As it wouldnt be for Nowt .

STREET rideing ! WHAT kind of Street ? ( Not those City ones ? :lol: ) Though if theres those Stop lamps . . . :P )

Race Prep ; some consider the old girls a bit of a Slug . Hence , as above : Check and inspect ALL components
If Going Into Battle . ( If he rides a Guzzi , he probably has STANDARDS ) a 4 S cam would wake it up , though I prefer
the ' 2 stage ' 2 S ( S S ) . With Either Id use 34 Mk 2 Amals or better , if you want to take on your Guzzi though .
Come to think of it , Its likely to have a perfectly good set of carburators . . . . :D

For Carveing up the Sceneary , Id use a 18 on the rear , or 16 If you take the kitchen sink touring . 4:10 & 4:25 (5:00/16 )
Being Italian you likely have a understanding of tyres . Japanese ones used to be plastic ( like their motorcycles , :oops: )


Hobots likely right on the Brake Mod . But he does Lumberjacking . If your from the City , a Desk Wallah ,pinch the Guzzi
master cylinder . ( They normally have nice rims too . )
yes , despite all the snivleing , most o.e.m. stuff is Top Notch . Though premature dementure allows some to consider
oriental aperatus of the period to be other than dysfunctional in regard to its roadholding - they were probably to pissed
to know the differance , or didnt try . . . yes . Anyway . :wink: )

The ' Transmission ' doesnt require a Liscence or degree to dismantle and inspect .You can throw in another cog or three , down low , to bring the gears in closer .Smallest one the Kick Start Pawl fits in . If youre going to cut a lot of miles , and someone offers you a Five Speed . Dont say No .

Most rubbers can be checked by standing on them with your heel .

Inspecting the mechanicals , if Florence Nightinggales not liely to be impressed , Neithers the Cheif .Cleanliness is Next to Godliness .
 
Dear Doug,

Congratulations on a rare find, that is very low miles, you lucky guy!
I can only add to to the advice already given, re the carbs. I would carefully check the pilot jets and passages, got to bushmans amal site for the full explanation. After that long lay up I would be surprised if the carbs are not blocked up. And yes new Anodised slides and new float needles and maybe replace the floats.
You will be rewarded. My mk11 had 14000 miles when I got hold of it, but is was cosmetically rough in the tanks etc. I left the bottom end alone after pulling the top end. Mine had water marks in the bores, but I just cleaned these up and put in new rings, and she ran fine to about 21000 miles when I decided to do the full strip.
Good luck Doug

Regards Richard
 
I tease thee not on poking out the master cylinder inner rubber valve boot tiny restristor.

Get the anodized slides Now to save the Amal bores for ever more.
Its ain't fuel deposits that clog Amal carbs its the zinc oxide so no solvent but too strong acid or alkaline can touch it expect pure poking a wire or #16 drill bit.
Beware old fiber glass tanks and new ethanol fuel, must seriously coat with special two part epoxy and can't store new age fuel very long of water gel collects.

The jug with the valve open may be rusted inside so better take head off and see.

Valve stem seals only needed on intakes that see intake sucktion.
Universal upgrade for oil weeps is the one way breaker PCV valves you can search for choises $5 type on up to $100+ custom types.

Glad another Commando and Commando man is coming on line.
 
hobot said:
I pure poking a wire or #16 drill bit.

If I may be so bold to correct, #78 drill bit. They are to short and tiny to get in there without glueing them onto an end of a q-tip stick. Buy 2 of them. When you drop one on the garage floor, it will be lost to these old eyes.
 
Nicely done. Much good advice so far. Had a '75 and found a soft cam. Not sure if there's a magic serial number after which the cams got better but...I'd lose it if it's apart. Electrics? Stock looms are fine given they haven't been trashed. I suspect you'd want to verify connections and clean contact points in switches.The only real issue I've had with a one owner '73 is a dirty kill switch and a broken 5 point connector uner the tank. Grease yer bearings and refresh all fluids. If yer worried about your top-end, rings etc...give Jeff a call at Redline.
 
I'd like to thank everyone who posted and PM's for the thoughtful and thorough responses.

I've considered all have decided to go the distance. Every component, bolt and nut will be taken apart, inspected and renewed if necessary. I am hoping the low original mileage will give me a great starting point.

It is certain I'll have more questions as I progress through the systems for everyone here and will post pictures here.

This board reminds me of the Guzzi folk - many helpful people and so much knowledge.

The cool thing about the Norton vs the Guzzi is the plethora of upgrades and options, although the amount of choices make project planning more complicated initially.

Again, thanks for all the great advice.

Best regards,

Doug Beck
Minneapolis, MN
 
Nice find! A lot of good advice has been given already. I expect you at least plan on new piston rings, so when you pull the barrels take a good look at the cam lobes. The cam lobes generally wear with a razor edge of metal left so you will easily notice cam wear with the cases in tact. If the cam looks good, you might want to take a chance and not split the cases. If it shows signs of wear.....well you know what you need to do.

The swingarm of a Mk3 is "permanently" lubed. They also are anchored with two wedge-shaped studs that lock the spindle in. It is doubtful it requires any service. However, if you plan to paint the frame, swingarm, and cradle, you will likely want to remove the swingarm for painting. You will need to remove the swaged plugs to remove the swingarm spindle. The end plugs will need to be replaced. The felt wicks inside should be soaked in 140 wt. oil when replacing the spindle.
 
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