Common Improvements

I wanted to talk about some common improvements that can be made to these bikes. Not talking about some silly inverted forks or mono shocks, or other junk from pipeburn. Also not talking about full on race stuff. Just simple things that offer some functional improvement. For my bike I want to do some of these things. I am not one for a factory restoration.

-Head steady? Mine is a 71 so I think I need the one with the spring thing? Are these worth the money? Anything else similar?

-MK3 Isolastics. Saw a few kits to include everything for around $300. One kit better then another?

-Alloy rims? If changing the wheels is there a better size to use? I know with the SOHC CB750 it is a good idea to run an 18in front in place of the 19.

-Are there rearset options?

-Hagon the standard rear shock?

-Right now I have a single Mikuni on the bike. Thinking about going back to the dual Amals though.

-Electronic ignition. When dealing with Hondas (what I know) I rarely use them as points are not a black art. Unsure if something changes for Norton.

-Progressive springs in the forks?

Would love to hear some comments about the modifications I listed as well as any input about ones I missed.
My goal with the bike would be to have a nice street bike that is fun to ride and has meaningful parts.

Thanks for the help

Right now my bike only has headers, so I will need to do something with the exhaust.
I happen to be a sucker for high pipes. Have seen some options for those.

jaguar said:

-Head steady? Mine is a 71 so I think I need the one with the spring thing? Are these worth the money? Anything else similar?

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The Dave Taylor head steady seems to be the most popular (Yes I've got one with spring) although there are other types.

jaguar said:

-MK3 Isolastics. Saw a few kits to include everything for around $300. One kit better then another?

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Basically, there are two vernier options, the 850 MkIII kit that requires the front Isolastic tube to be shortened or replaced with the MkIII front Isolastic mounting, or, the vernier conversion kit which fits the pre-MkIII models without any modifications.

jaguar said:

-Alloy rims? If changing the wheels is there a better size to use? I know with the SOHC CB750 it is a good idea to run an 18in front in place of the 19.

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Wider rims are certainly an option and possibly 18 inch rear.

jaguar said:

-Are there rearset options?

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Yes, although you may have to hunt around for a good set or, make them yourself?

jaguar said:

-Hagon the standard rear shock?

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Girling, originally, Hagon carried on with the design where Girling left off, some riders like Hagons and some do not (OK I like them), but there are better shocks available such as Ikon (the old Konis).

jaguar said:

-Right now I have a single Mikuni on the bike. Thinking about going back to the dual Amals though.

Click to expand...

Horses for courses, so ultimately it's your choice.

jaguar said:

-Electronic ignition. When dealing with Hondas (what I know) I rarely use them as points are not a black art. Unsure if something changes for Norton.

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The approach wouldn't be much different for a Norton although the AAU can wear and the springs stretch and cut into their posts which can affect the timing accuracy.

jaguar said:

-Progressive springs in the forks?

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Jury's still out on that one! Personally I've found the RGM Motors progressive springs to be an improvement but I can't comment about other Norton progressive springs.

jaguar said:

Would love to hear some comments about the modifications I listed as well as any input about ones I missed.
My goal with the bike would be to have a nice street bike that is fun to ride and has meaningful parts.

Click to expand...

I would certainly recommend the Lansdowne fork damper kit. http://lansdowne-engineering.co.uk/three_3.html

Oh, and probably a front brake upgrade of some description such as having the master cylinder re-sleeved down to 1/2" or 13mm.

And.....a dynodave clutch pushrod seal.

So many improvements without over doing it, if you got a good bank account the world is your oyster, every one has a diffrent opinion and I have been improving my Norton for 40 years now and it has never let me down in those 40 years, when I first started on my Norton when I was young there were not that much stuff to improve them with electronic ignitions (Boyars was the go in them days) where just starting to come on the market, but now so many diffrent brands, I now run a new Joe Hunt maggie, frontends were good but its only was oil or springs you could change, but now have better internals, I started with Progressive springs, but soon spent the money and went Lansdown internals but works better with stock springs, rear shock where one of the first things I changed in my first few years from new, (Konis were the go in them days and I still using them after 35 years on the bike (rebuilt for the first time last year) then there the handling, in 1980 I went completely diffrent and converted my 850 to the Featherbed frame, in your case late model Isolastics is the go,, alloy rims are the go and in 1980 I replace my rims with Arkront rims but in the same size (they were cheap in them days and still look good now).

This is only a few things then there the motor, you can spend a lot of money there, from basic rebuilds to going way over budget, then theres the carbies, I am a beleiver of twin carbies, so there are many brand on the market that will improve the performance but the new Premers are the way to go and looks right, it all boils down to how much money your willing to spend, sometimes you don't need to spend heaps of money to have a reliable bike, but its realy up to you how far you want to go.

Ashley

The linked document is a little out of date now but aims for a robust go-anywhere-anytime condition.
Ta.
https://www.dropbox.com/s/5aquwqwqjis4n ... N.doc?dl=0

L.A.B. covered the points quite nicely. I would comment on some items from personal experience:

Carb(s) - I converted from the stock, worn-out twin Amals to a single 34mm Mikuni. It pulls like a train up to 90 mph, then no more. That's plenty for any "legally" ridden street bike. 'Love the cold-start enricher system! Routinely returns 57 mpg in mixed driving.

Front brake - Went with a flea-bay cheapo 12mm M/C and Ferodo pads. Two-finger braking. I'll be sleeving the stock cylinder as funds allow so as to get the original look back.

Gearing - Converted the front sprocket to 22 tooth since most of the saddle time is on the open road. It didn't seem to cut much into the acceleration, but it's a '74 850 with a bit more mid-range torque than the 750's. That's one of those things you tailor to the predominant usage.

Clutch - Let's not go there again! clutch-slippage-part-enter-your-number-here-t22376.html

Nathan

The commando's biggest flaw was crankcase pressure. You can go a few ways here. You can have your cases modified by jim comstock for a combat style breather, or buy his bolt up sump breather if you don't have an early frame with it's crossmember in the way, or you can do a timing chest modification of some sort... IMO, a breather mod is a necessity for parallel twins.

If you have an early frame with only a single bolt in the cradle swingarm tube, you should do the kegler modification, because without it you are wasting you money only buying new isolastics.

I went with a comstock headsteady (rose joint type) the dave taylor brand works too, but is less burly than the comstock verion which also has sealed bearing so it doesn't need oiling, nor drip oil on your engine.

I went with Koni shocks 20 years ago. progressive springs with 3 preload settings and adjustable damping

steel gas tank -

boyer (or some other electronic ignition) and a 3 ohm dyna dual lead coil. What vehicle made today still has points? Electronic ignition and a single coil with aplastic jacketing and dual leads is a "set it and forget it" replacement for Points, condenser, metal jacketed coils, balast resistor, and mechanicial advance unit... Seems like a no brainer to me, but there are always people who swear by points...

replace 19 tooth with 21 tooth final drive sprocket. makes the rpms a little easier on the bike at hiway speeds without gutting the bike's powerband.

jaguar said:

I wanted to talk about some common improvements that can be made to these bikes. Not talking about some silly inverted forks or mono shocks, or other junk from pipeburn. Also not talking about full on race stuff. Just simple things that offer some functional improvement. For my bike I want to do some of these things. I am not one for a factory restoration.

-Head steady? Mine is a 71 so I think I need the one with the spring thing? Are these worth the money? Anything else similar?

-MK3 Isolastics. Saw a few kits to include everything for around $300. One kit better then another?

-Alloy rims? If changing the wheels is there a better size to use? I know with the SOHC CB750 it is a good idea to run an 18in front in place of the 19.

-Are there rearset options?

-Hagon the standard rear shock?

-Right now I have a single Mikuni on the bike. Thinking about going back to the dual Amals though.

-Electronic ignition. When dealing with Hondas (what I know) I rarely use them as points are not a black art. Unsure if something changes for Norton.

-Progressive springs in the forks?

Would love to hear some comments about the modifications I listed as well as any input about ones I missed.
My goal with the bike would be to have a nice street bike that is fun to ride and has meaningful parts.

Thanks for the help

Click to expand...

My list (assuming stock, well sorted power unit)

1) re-wire and convert to single point ground (positive/negative don't matter as much)
2) solid 3 phase charging system (with unified reg/rec) feeding top quality, sealed battery
3) taylor head steady + mick hemming adjustable ISO caps (IMO, much better option than the vernier set up for pre mark III's )
4) mac master carr (or similar) rubber ISO mounts
5) kegler swingarm collars for pre Mark III's (whichever bush system you use you should have these installed)
6) keihen flatslide carbs, 2 of them (or the the new smoothbores if you can afford them)
7) oil pump rebuild + timing cover anti sump mod (AMR)
8 ) new sump plug with magnetic drain plug (to drain what the above still lets through)
9) cut the lug off the bottom of oil tank, weld plate to stiffen and seal and cracks, support on a rubber pad (a'la CNW)
10) tri spark
11) braided oil rocker and brake lines (if running disc), if running drum - stiffening kit
12) upgraded fork internals (either js bushes, or lansdowne damper kit) with no leak seals
13) XS650 valve on engine breather, + a breather in the gearbox

everything else is gravy to "customize" the machine, I didn't list a belt drive as others might, even though I now have one, as the benefits over a chain are not IMO as pronounced as those i've listed over their stock counterparts

Swing arm spindle?

There are only a few mods that I consider must-have's, that have made a huge difference in rideability and reliability for my 850...

Sleeved front disc m/c
Electronic ignition (take your pick which one)
Tach drive oil seal mod - keeps oil off your right foot
High output alternator - charge the battery even at idle
Halogen headlamp
Clutch stack shim and Dyno Dave's oil seal.

jaguar said:

Swing arm spindle?

Click to expand...

early bikes only had a single bolt through the swingarm tube which is on the enging cradle. The lateral forces exherted on the tube from the swingarm create a lot of play in the swingarm tube/ swingarm shaft. Later model swingarms had 2 threaded set screws to pin the swingarm shaft in the cradle tube to eliminate play there.. Even if your swingarm bushings are tight, if you have play in the tube/shaft, then your handling will be sloppy because of that play....

Lateral play, and a sloppy snakelike handling feel, can often be traced to a few things which ALL must be good. Isolastics spacing, swingarm bushings, swingarm tube/shaft play, wheel bearings, and headsteady.

Here's the best pictures that I've found to explain it. It's actually and easy modification to make and the parts can be cheaply found on Mcmaster-Carr

http://www.nortonfastback.com/html/mods.html


*** There are people here who have taken eliminating lateral play in their handling to even higher levels, adding "rose joint" style stays to the front and back isolastics locations to get the sort of rigidity that isolastic mounted engines never had anything close to...

Stock length rear shocks?
Or something slightly longer?

I have a WM-3x18 shouldered alloy rim on the rear (stock is WM-2x19) and a 4.00x18 tire. It nearly rubs the chainguard. I previously used a 4.25x18 tire and it had to be shaved on the edge to clear. Not sure if a wider rim/tire combination could possibly fit. Had a 110/90x19 front tire and changed that to a 90/90. This makes the rear look proportionately larger. No verdict yet as to the performance of this combo, but it looks good!

Definitely upgrade the crank breather somehow.

Another option on the isolastics is the Hemmings adjuster, it's only about $100 and you keep all your parts, just replace one of the end caps on each and now don't need shims. Works on any year Norton with no mods.

Definitely the Keigler mod for the swing arm.

Better style headsteady good idea, the spring helps keep the iso's from sagging.

Better brakes are nice.

Anything else is pure gravy and up to your desire.

o0norton0o said:

Later model swingarms had 2 threaded set screws to pin the swingarm shaft in the cradle tube to eliminate play there..

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Mk3 models had the spindle was secured with two cotter pins (&nuts).

Jag ... you asked 'bout shock length ... I think stock is good I used the black spring Hagons ... work well for me ... front brake was up graded with CNW brembo master , stainless hose , ferodo pads and caliper kit ... good stopping now ... Lansdowne fork upgrade with fork rebuild kit and new stock springs made a huge improvement ... I sit on a Corbin gunfighter and hang onto euro spec bars with bar end mirror ... all other mods have already been mentioned although good tires help a lot too ...
Craig

I will need to read up on the spindle mod and breather.

first need to get a list of basic service items and dig into the bike first.
But want to start ordering add ons as well.

You'll get a thousand answers here.....'my 2 cents,spend money wisely and spend it only once !! The best phone call you'll ever make is to Matt at CNW Colorado norton works.... He has it down to a art form and can help you manage your upgrades appropriately

Its takes a few years to cover the scope of upgrades and then staying current but it can take a decade or more to really learn historic lore and old school mods and workarounds for the quirks common to em all and those on your particular luck of the draw Commando. If I knew what I know now I would of should traded my titled core towards a ready to go customized as I wanted CNW number- with a Kleenex dispenser for the gals to wipe their tears and dudes their weepage. To me and handful of others stopped short in our tracks just wandering around a rally to see a new on on back of a van, flat floored our jaws to the ground, more so than all the others than prior acrers of em kind of numbs ya pleasants so all the more note worthy of how striking beautiful deep to the join sensation. A freaking bargain basement turn key - if like me really only want to be a pilot with the time left me. If ya really wanted to surge have Matt stick in a 920 engine from Kenny Cummings and TTI New Zealand gearbox and give Comstock 4grand to refit one of his spare fuel injection ignition system and half that for the final belt drive. Check in out here for some ancient mussings on what to do with this and that.
http://www.captain.norton.clara.net/

For those with a death wish $3500 might still be able to snag a read to fly Drouin power adder on the above.

ludwig said:

What I would take off the list :

1. Vernier isolastics .
IMO , a waste of money .
With a good headsteady , isos will stay within spec. 30 - 40000 km .
How many km do you plan to ride each year ?
2 . Progressive springs .
Most so called 'progressive' fork springs are not progressive at all ( within our operating range ) .

Spend your money on :
1. brakes .
2.Headsteady .
3. Swingarm spindle fix .
4. Belt drive .

Click to expand...

+1
Get your brakes working first. It is 2015 not 1972. Our cars have changed to better ABS disk brakes and so should you improve your rig. I use the sleeve kit from RGM. CNW is top notch but depending on budget...
Head steady: There are many types on the market but if you have the old 750 style get this done next. Search this site for options.
I use landsdown front Ikon rear but you can search for Covenant Conversion if you want to go on the frugal.
Belt drive Primary is the way to go but not important until you fix the first steps. Then work on engine to fix leaks and reliability issues.
Gearbox...You must check the layshaft bearing...again do searches on this site.
Do everything in steps change one thing at a time.
The more you do the more you enjoy your ride.
Good Luck

Cheers,
Thomas
CNN