noob, first post, and my 74 commando project

hello - name is joe, noob, and first post. I 've been wanting a new project, and always wanted to do a classic british bike. long story short, recently picked a rather nice, somewhat original, 74 Norton commando 850, roadster in (original paint) candy apple red - 16.7K on the clock and appears to be original miles. frame, engine, and transmission numbers match, and overall, the bike is in pretty nice condition considering it's 45 years old. one minor problem, it doesn't run. wiring is an absolute mess - seems the previous owner got in over his head and that's when things went south. anyway, i'm always up for a challenge, so I thought i'd give this a try. I've sorted through 99% of the wiring and ID'd most everything. right now, a factory service manual and lucas main harness are on their way. in the mean time, I've been doing piece/part cleaning, detailing, and reconditioning.

the bike came with a mikuni single carb conversion, podtronics rectifier/regulator, a half installed tri-spark ignition, and a Colorado Norton works, hydraulic clutch conversion. along with the bike came a new corbin, two tone, café racer style seat, original ignition, carbs and air cleaner, original mufflers, assorted original parts, and an additional boyer-bransden ignition system.

so in the future, I will have a ton of dumb questions, so bare with me. for now, i'd like to share a few pics...









joe czech

NICE!!

Hook up the Tri_Spark but get rid of that Mikuni and put a pair of Amals back on (new set of Amal Premiers). Then it will run like it's GOT A PAIR!

You've got what seems to a really good base for restoration. I started my Commando journey just over a year ago and can tell you it is very rewarding.
Some things I've had to do on my '74 850, (with 8300 original miles when I got it):

Ignition switch was faulty (irratic starting, flaky contacts) and I could not restore it so replaced with aftermarket.
Cleaning up all the grounds and component connections made running volts much higher.
Fitting a PCV type check valve to the breather line solved a number of small oil leaks, esp around rocker covers.
Wet sumping lead to a blown oil seal on my bike at the crank in the primary case. Number of solutions for this, including doing nothing at all. I made a manual ball valve with integrated electrical switch to prevent power to ignition if I forget to open the valve.
Intake valve seals eventually started passing oil into cylinders...the seals were brittle when I swapped in fresh Viton rubber ones (without needing to pull head). No more smoke on blipping throttle.

dumb question #1 - not sure if i'm reading this right. the tires on the bike (avon roadrunners) look absolutely new - look like they don't have but a couple hundred miles on them - even have molding nubs on the tread. anyway, not sure if i'm reading the date code right. always thought if it had 4 digits on the code, the manufacturing date was after y2k or 2000, with the first two digits. being the month, and the last two, the year. my date code is alpha-numeric - being C086. am I reading this right as 1996 - if so, 23 year old tires -

don't see pics

joe czech said:

not sure if i'm reading the date code right. always thought if it had 4 digits on the code, the manufacturing date was after y2k or 2000, with the first two digits. being the month, and the last two, the year. my date code is alpha-numeric - being C086. am I reading this right as 1996 - if so, 23 year old tires -

Click to expand...

Yes, although the first two digits are week (08)

https://www.vintagetyres.com/tools/


"1990-1999
The date code is three digits long. For the Nineties this was followed by a triangle. The first two digits represent the week of production, the third digit represents the year. The tyre in the picture was made in the first week of 1996 (note the small triangle on the right)."

I'd recommend fresh rubber before any serious miles on the bike. No matter how good your old ones look. Motorcycle tire rubber is a softer compound than road cars and will degrade faster with simple oxidation. I'd say 3-4 yrs is a max safe life for a bike tire that I would feel comfortable riding on at speed.

Yep, sadly that tire is out of warranty! A max of 10 years is the current recommendation on replacing tires based on age alone. It used to be 5-8. I guess they make them better now.

FWIW, a manufacturer tire warranty is based on the build date, not the sold date. IOW, if you bought a "new" tire that happened to be "on the shelf" for a year, that year is part of the warranty period.

thanks for the heads up on the tires - verified my thinking. most likely, i'll replace the tires after everything's sorted and I feel comfortable getting this thing on the road, but for testing and short shake down cruises, they should suffice. couple things on previous posts - PCV check valve to the breather, and the amal premiers carbs. most likely, i'll follow up for some more questions and information. again thanks!

You will also need to consider brake upgrades as stock MC with stock caliper is very marginal performance. Rear drum is just plain ineffective.
I sleeved my stock MC to 1/2" which brings the ratio to the caliper pistons to something more modern. Performance is close to my 2013 Bonneville front disc. Sleeve kit I used came from forum member @madass140 (has a Web page showing all his products). You can change out MC to a modern setup and even go full on with better disc/caliper designs. Have not seen any real upgrades for rear drum, but there are examples of converting to rear disc out there.

Send that drum rear brake to Vintage Brake and you’ll get back an excellent stopper. Very progressive brake.