Restoring my 73' 850 Commando

Chris Larkin · Feb 13, 2020

Working with a bike mechanic I trust, who prefers to work on Harley's... we’ve come to the conclusion my 73’ 850 Commando is worth restoring.

So far I’ve replaced the tires with Avon AM26’s and replaced the points with a Tri Spark ignition. It idles well, runs OK, but stutters at higher rpms. Both cylinders tested out at 120psi compression. I’ve done some fundamental polishing and it is responding well to the care. But I want it to be better – with the goal of keeping it original as possible.

I believe I need to tear down to the frame because many of the foundation parts (bushings, rubber dampeners, etc.) are worn, and a safety concern, thus prompting the restore / replace before I get into serious riding.

My purpose for writing today is to start a thread where I can connect with members who have experience with this process, with whom I can turn to with questions and such. I see it taking a year, hopefully less, but my time is limited to weekends and when I’ve not been assigned home landscape chores on the weekends.

Step one… I should probably get a book on this… yes? May I have a recommendation, or two? Thank you, Chris

NickZ · Feb 13, 2020

Chris Larkin said:
Working with a bike mechanic I trust, who prefers to work on Harley's... we’ve come to the conclusion my 73’ 850 Commando is worth restoring.

So far I’ve replaced the tires with Avon AM26’s and replaced the points with a Tri Spark ignition. It idles well, runs OK, but stutters at higher rpms. Both cylinders tested out at 120psi compression. I’ve done some fundamental polishing and it is responding well to the care. But I want it to be better – with the goal of keeping it original as possible.

I believe I need to tear down to the frame because many of the foundation parts (bushings, rubber dampeners, etc.) are worn, and a safety concern, thus prompting the restore / replace before I get into serious riding.

My purpose for writing today is to start a thread where I can connect with members who have experience with this process, with whom I can turn to with questions and such. I see it taking a year, hopefully less, but my time is limited to weekends and when I’ve not been assigned home landscape chores on the weekends.

Step one… I should probably get a book on this… yes? May I have a recommendation, or two? Thank you, Chris

Do you have the workshop manual?

http://britmoto.com/manuals/Manuals/750_man.pdf

grandpaul · Feb 13, 2020

Whatever you plan to spend, DOUBLE IT! hee hee
Good to have a "known quantity" before you start. Starting with a basket case or non-running project is much harder.

gortnipper · Feb 14, 2020

Welcome!

My advice would be:

Read a lot of the threads on this sub forum.

There is a lot of reference material here

https://www.accessnorton.com/NortonCommando/technical-information.2265/

Print out the workshop and parts manuals.

Use the visualizations with the parts list at https://andover-norton.co.uk/en/shop-drawings/5

Ask lots of questions, even if you think they are dumb. At least 100 people before us have been through it all 100 times before.

Have fun!

Bernhard · Feb 14, 2020

Re; " it stutters at higher revs" it may be the fuel system is overdue a good clean, remove petcocks an clean and flush tank out, ditto carbs float bowls, you may need new needles and needle jets. Have you checked charging system with multimeter across battery terminals? Electronic ignition does not like being starved of current.

Richard Tool · Feb 14, 2020

Hi Chris and welcome - lots of knowledge available on this site from some very experienced folks . Joining up here is probably the single best thing you could have done for help in your project. I agree with the others on obtaining shop and parts manuals and also use of Andover Norton’s site - excellent drawings & photos.
For cleaning out carbs and other fuel system bits I use an inexpensive ultrasonic cleaner . Mine came from Harbor Freight and IIRC it was around $70- $80 . Well worth the minimal investment.
If you are getting in to the engine and/or gearbox get the Mick Hemmings videos available from the UK based Norton Owners Club. NOC is also an excellent source of information, particularly for older non-Commando models.
We all love to follow other people’s efforts so by all means post your efforts here - pictures are a plus.

Chris Larkin · Feb 14, 2020

NickZ said:
Do you have the workshop manual?

http://britmoto.com/manuals/Manuals/750_man.pdf

Not this one - Thank you

Chris Larkin · Feb 14, 2020

gortnipper said:
Welcome!

My advice would be:

Read a lot of the threads on this sub forum.

There is a lot of reference material here

https://www.accessnorton.com/NortonCommando/technical-information.2265/

Print out the workshop and parts manuals.

Use the visualizations with the parts list at https://andover-norton.co.uk/en/shop-drawings/5

Ask lots of questions, even if you think they are dumb. At least 100 people before us have been through it all 100 times before.

Have fun!

Very helpful materials & advice - Thank you

Chris Larkin · Feb 14, 2020

Bernhard said:
Re; " it stutters at higher revs" it may be the fuel system is overdue a good clean, remove petcocks an clean and flush tank out, ditto carbs float bowls, you may need new needles and needle jets. Have you checked charging system with multimeter across battery terminals? Electronic ignition does not like being starved of current.

Locally, this was suggested as a possible symptom... also contributing to the reason to restore. These tasks will a part of the project - Thank you

Chris Larkin · Feb 14, 2020

Richard Tool said:
Hi Chris and welcome - lots of knowledge available on this site from some very experienced folks . Joining up here is probably the single best thing you could have done for help in your project. I agree with the others on obtaining shop and parts manuals and also use of Andover Norton’s site - excellent drawings & photos.
For cleaning out carbs and other fuel system bits I use an inexpensive ultrasonic cleaner . Mine came from Harbor Freight and IIRC it was around $70- $80 . Well worth the minimal investment.
If you are getting in to the engine and/or gearbox get the Mick Hemmings videos available from the UK based Norton Owners Club. NOC is also an excellent source of information, particularly for older non-Commando models.
We all love to follow other people’s efforts so by all means post your efforts here - pictures are a plus.

Thanks for the information and encouragement. I will post picks. I'm also considering collecting periodic video for a "if this dummy can do it, so can you" type instructional. I'll look into the cleaner - thanks

Chris Larkin · Feb 14, 2020

I forgot to mention in in San Diego, CA USA - I'd be stoked if y'all have any recommendations for people or shops to reach out to for service. I'm acquainted with a few folks who seem to know Norton's - but the more contacts the better. Thank you.

gortnipper · Feb 14, 2020

+1 on the Mick Hemmings DVDs. They were invaluable learnings from a guru.

http://bracebridge-street.com/tech.htm

Also, for more great videos and technical info Jim Comstock (comnoz here on AN) is right there with him. Trust him. He has great videos on his you tube channel under James Comstock.

Also check out the Mi Ty channel for great rebuild videos. Very wel presented.

Chris Larkin · Feb 18, 2020

gortnipper said:
+1 on the Mick Hemmings DVDs. They were invaluable learnings from a guru.

http://bracebridge-street.com/tech.htm

Also, for more great videos and technical info Jim Comstock (comnoz here on AN) is right there with him. Trust him. He has great videos on his you tube channel under James Comstock.

Also check out the Mi Ty channel for great rebuild videos. Very wel presented.

This is all incredible... great resources - Thank you

Scout63 · Feb 18, 2020

Best of luck Chris. The forum was invaluable in my restoration and pushed me to a level of care that would have been impossible. Not knowing what you don’t know is a killer. +1 on the Norton workshop and parts manuals and I found Old Britts to be a great resource for parts and technical articles. And without pictures it never really happened.

Chris Larkin · Feb 19, 2020

Scout63 said:
Best of luck Chris. The forum was invaluable in my restoration and pushed me to a level of care that would have been impossible. Not knowing what you don’t know is a killer. +1 on the Norton workshop and parts manuals and I found Old Britts to be a great resource for parts and technical articles. And without pictures it never really happened.

Thank you, you have confirmed my process so far... - I have the manuals, book-marked multiple on-line vids, and have become friendly with Ella and Fred at Old Britts... After my son's wedding this weekend, then a 5 day snowboarding trip to Idaho... I begin by starting with carb rebuilds.

NPeteN · Feb 19, 2020

If youre going into the gearbox buy the Hemmings DVD. Next best thing to having someone walk you through it in person.

Chris Larkin · Feb 19, 2020

NPeteN said:
If youre going into the gearbox buy the Hemmings DVD. Next best thing to having someone walk you through it in person.

I will - Thank you

eskasteve · Mar 16, 2020

Phil Radford is a hell of a guy. Not sure how close you are to him.
Fair Spares America, Inc.
P.O. Box 6781
Los Osos, CA 93412
USA
New Phone: +1 (805) 534-9248
New FAX: +1 (805) 534-9249

Chris Larkin · Mar 17, 2020

eskasteve said:
Phil Radford is a hell of a guy. Not sure how close you are to him.
Fair Spares America, Inc.
P.O. Box 6781
Los Osos, CA 93412
USA
New Phone: +1 (805) 534-9248
New FAX: +1 (805) 534-9249

You're the third endorsement of Phil / Fair Spares. I've received his catalog and will be certain to contact him with questions - Thank you

eskasteve · Mar 17, 2020

Phil is one of the good guys out there. He always seems to have the time to discuss Nortonisms with his customers.

Restoring my 73' 850 Commando

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