cNw #101 Norton Commando 850

There is another maintenance topic with these carbs.

The float needle housing O ring, #37 in the diagram above, can perish over time (no doubt exacerbated by ethanol fuel).

When this happens, fuel will pass by the O ring, thus bypassing the float valve, thus causing flooding. This would cause excess fuelling at low throttle openings and could therefore cause idle issues. At bigger throttle openings, the fuel will be used and the float level will therefore drop and be ok.

This is also why these carbs should never be left with the fuel taps on IMO. If the taps are left on and you have a leaky O ring, then due to the design of the carbs and the angle they’re mounted at, and if your filter stubs are designed to divert air to the pilot circuit through the air filter, then fuel will basically fill up the carb and enter the inlet port where it will then run down the port and into the engine.

To further complicate this issue, the O ring is specific to this application and is a smaller section than standard O rings. Standard o rings will not fit, and if you force them, will cause the housing to be cock-eyed, or the O ring to be damaged, or both. Even some rebuild kits from specialist (inc a certain well known U.K. supplier) include the wrong o rings for this !

I get my Keihin parts from here, I’ve not had any issues thus far:

Security measure

www.ebay.co.uk www.ebay.co.uk
 
Fast Eddie said:
There is another maintenance topic with these carbs.

The float needle housing O ring, #37 in the diagram above, can perish over time (no doubt exacerbated by ethanol fuel).

When this happens, fuel will pass by the O ring, thus bypassing the float valve, thus causing flooding. This would cause excess fuelling at low throttle openings and could therefore cause idle issues. At bigger throttle openings, the fuel will be used and the float level will therefore drop and be ok.

This is also why these carbs should never be left with the fuel taps on IMO. If the taps are left on and you have a leaky O ring, then due to the design of the carbs and the angle they’re mounted at, and if your filter stubs are designed to divert air to the pilot circuit through the air filter, then fuel will basically fill up the carb and enter the inlet port where it will then run down the port and into the engine.

To further complicate this issue, the O ring is specific to this application and is a smaller section than standard O rings. Standard o rings will not fit, and if you force them, will cause the housing to be cock-eyed, or the O ring to be damaged, or both. Even some rebuild kits from specialist (inc a certain well known U.K. supplier) include the wrong o rings for this !

I get my Keihin parts from here, I’ve not had any issues thus far:

Security measure

www.ebay.co.uk www.ebay.co.uk
Click to expand...
A useful resource, saved seller. thanx
 
Managed to take advance some nice weather today and have a fairly short ride to compare a couple of mirror choices and to test the outstanding idle issue.

From cold the bike ran flawlessly and I even managed to only have one false neutral (usually pretty common for me changing down from 4th to 3rd) when I forgot to be more positive than I’m used to with the Kawasaki W.

Overall an excellent ride albeit short, just flowed nicely and allowed me to fully engage with the bike’s personality which it has in volumes; rolling on with this bike is soooo addictive.

I also tested the Auto Meter speedo for accuracy (thanks RobSS for the tip) with an GPS IOS app and it’s bang on meaning Matt did an excellent job of calibrating it. And also thanks to RobSS for the tip of fitting a Paul Goff Daylighter 2 LED headlight bulb, super bright with excellent high/low beam pattern.
Matt did warn me of the bikes potential thirst with these FCR 35s but I’ve filled 3 times and achieved 55-57mpg even with some spirited riding so no complaints:); I was fearing sub 40 or worse 😫
 
Café au Lait said:
Managed to take advance some nice weather today and have a fairly short ride to compare a couple of mirror choices and to test the outstanding idle issue.

From cold the bike ran flawlessly and I even managed to only have one false neutral (usually pretty common for me changing down from 4th to 3rd) when I forgot to be more positive than I’m used to with the Kawasaki W.

Overall an excellent ride albeit short, just flowed nicely and allowed me to fully engage with the bike’s personality which it has in volumes; rolling on with this bike is soooo addictive.

I also tested the Auto Meter speedo for accuracy (thanks RobSS for the tip) with an GPS IOS app and it’s bang on meaning Matt did an excellent job of calibrating it. And also thanks to RobSS for the tip of fitting a Paul Goff Daylighter 2 LED headlight bulb, super bright with excellent high/low beam pattern.
Matt did warn me of the bikes potential thirst with these FCR 35s but I’ve filled 3 times and achieved 55-57mpg even with some spirited riding so no complaints:); I was fearing sub 40 or worse 😫
Click to expand...
What more could be asked for out of a motorcycle: fun to ride and excellent fuel economy and awesome to look at
 
Having had the bike on the road for nearly a week and about 200 miles, some observations.

For me the ergonomics are just about perfect, neither stretched or cramped; a small amount of forward lean, noticeably less than my W800, works a treat at speed but no issue in traffic though I’m still trying to get used to the somewhat fat grips Matt’s used at least compared to what I’m used too. Footrests, rear brake and gear selector are in just the right place, I’ve no desire for rearsets but the brake takes some travel before any decent engagement and the gear selector is strangely lacking in projection compared to the footrest resulting in some tip of the toe action or fluffing of the change, something I’ll adapt to.

The Honda cubes are good but the indicator control is squidgy, lacking precision but I’ll spray some switch cleaner into see if I can make it more positive.

The idiot lights are super bright, no complaints but the horn is weedy, something to replace and reposition.

Suspension is very good and confidence inspiring but the tyres are liable to track, not as bad as the awful OEM Dunlops on the W but short of the RoadRiders I replaced them with. The ride is firm but very comfortable though despite the higher pressure Matt recommends, 33/38 (W 33/36), potholes cause less of a problem bizarrely but longitudinal grooves make the whole bike oscillate a bit; Bix to Nettlebed in Oxfordshire being my test strip, truly awful stretch of tarmac which the RRs cope with very well. I’d say the Bridgestones are on par with the Ceats on my Enfield in this regard.

The Gunfighter saddle, despite offering only one position really and quite wide at the tank fits like a glove and although very firm is super comfortable, so far at least.

Brakes are good to very good but I would as yet call them great considering their spec but time make change that opinion.

Handling is very good inasmuch as I’ve pushed it which isn’t so much as I’m learning the bike’s dynamics and the front tyre is brand new. However it’s not twitchy in any way, surefooted but needs some input in tighter bends, something I’m used to with the Kawasaki; it’s not the kind of bike that steers itself let’s say.

I’ve not owned a 4 speed bike before it unlike my other 2 I don’t find myself looking for another gear, 4 really is enough on this machine though trying to maintain 20 mph is a PITA at times not really suiting 2nd or 3rd. #101, like many dry clutch Commandos features a little squeal when pulling away, it bothers me not.

cNw ES is as good as its reputation, instant but nothing quite beats the joy of kicking this beast over, pretty much always a 1st kicker; the looks I received at the petrol station today were priceless and Arnie burst into life!

Riding down tight and narrow lanes is a bit tiring after a while, the bike wanting to get going rather than potter. The open, twisty larger B and A roads is it’s natural hunting ground of course and what a heap of fun it truly is, accelerating out of bends with the pipes blaring and all the induction roar from the K&Ns is just the bollox!

And then, when the ride is over and you dismount, take in that unique smell that modern bikes have lost and then savour the joy of just admiring this so special a bike Matt built is the icing on the cake, a thing of true beauty. Exquisite detailing throughout, I could look at it all day long.

To top it all is the realisation that I’m in possession or a truly great historical mark in motorcycle history, in exactly the same way as owing my Elise, something after 25 years of ownership I still have to pinch myself over and the Norton will no doubt never elude either.

Simon
 
Last edited:
The joy never fades even after 48+ years, glad you are enjoying it, just looks like minor adjustments for your fit, but it will get better after you learn all it's ways.
 
Café au Lait said:
Managed to take advance some nice weather today and have a fairly short ride to compare a couple of mirror choices and to test the outstanding idle issue.
Click to expand...
Can't go past Halcyon 830 bar-end mirrors as far as I'm concerned:
1. They really are excellent quality
2. They're heavy, so further damp bar vibes
3. They can be folded out of the way - with adjustable tension

Just bought another set for the 650ss - https://www.ebay.com.au/itm/275867510197

Cheers
 
robs ss said:
Can't go past Halcyon 830 bar-end mirrors as far as I'm concerned:
1. They really are excellent quality
2. They're heavy, so further damp bar vibes
3. They can be folded out of the way - with adjustable tension

Just bought another set for the 650ss - https://www.ebay.com.au/itm/275867510197

Cheers
Click to expand...
Matt fitted Arlen Ness Harley mirrors originally which look cool being quite tiny and I sourced a knock off pair which look identical but as Bill told me turned out useless as mirrors, all I see is my forearms. He replaced them with Arlen Ness oval chrome mirrors which were badly pitted but he left me a new right side spare. It looks ok and I can see a bit more but they are flat glass so the FOV is very limited and cars look closer than they are. I may well bite the bullet and go with the 830s after all.
 
Café au Lait said:
Having had the bike on the road for nearly a week and about 200 miles, some observations.

For me the ergonomics are just about perfect, neither stretched or cramped; a small amount of forward lean, noticeably less than my W800, works a treat at speed but no issue in traffic though I’m still trying to get used to the somewhat fat grips Matt’s used at least compared to what I’m used too. Footrests, rear brake and gear selector are in just the right place, I’ve no desire for rearsets but the brake takes some travel before any decent engagement and the gear selector is strangely lacking in projection compared to the footrest resulting in some tip of the toe action or fluffing of the change, something I’ll adapt to.

The Honda cubes are good but the indicator control is squidgy, lacking precision but I’ll spray some switch cleaner into see if I can make it more positive.

The idiot lights are super bright, no complaints but the horn is weedy, something to replace and reposition.

Suspension is very good and confidence inspiring but the tyres are liable to track, not as bad as the awful OEM Dunlops on the W but short of the RoadRiders I replaced them with. The ride is firm but very comfortable though despite the higher pressure Matt recommends, 33/38 (W 33/36), potholes cause less of a problem bizarrely but longitudinal grooves make the whole bike oscillate a bit; Bix to Nettlebed in Oxfordshire being my test strip, truly awful stretch of tarmac which the RRs cope with very well. I’d say the Bridgestones are on par with the Ceats on my Enfield in this regard.

The Gunfighter saddle, despite offering only one position really and quite wide at the tank fits like a glove and although very firm is super comfortable, so far at least.

Brakes are good to very good but I would as yet call them great considering their spec but time make change that opinion.

Handling is very good inasmuch as I’ve pushed it which isn’t so much as I’m learning the bike’s dynamics and the front tyre is brand new. However it’s not twitchy in any way, surefooted but needs some input in tighter bends, something I’m used to with the Kawasaki; it’s not the kind of bike that steers itself let’s say.

I’ve not owned a 4 speed bike before it unlike my other 2 I don’t find myself looking for another gear, 4 really is enough on this machine though trying to maintain 20 mph is a PITA at times not really suiting 2nd or 3rd. #101, like many dry clutch Commandos features a little squeal when pulling away, it bothers me not.

cNw ES is as good as its reputation, instant but nothing quite beats the joy of kicking this beast over, pretty much always a 1st kicker; the looks I received at the petrol station today were priceless and Arnie burst into life!

Riding down tight and narrow lanes is a bit tiring after a while, the bike wanting to get going rather than potter. The open, twisty larger B and A roads is it’s natural hunting ground of course and what a heap of fun it truly is, accelerating out of bends with the pipes blaring and all the induction roar from the K&Ns is just the bollox!

And then, when the ride is over and you dismount, take in that unique smell that modern bikes have lost and then savour the joy of just admiring this so special a bike Matt built is the icing on the cake, a thing of true beauty. Exquisite detailing throughout, I could look at it all day long.

To top it all is the realisation that I’m in possession or a truly great historical mark in motorcycle history, in exactly the same way as owing my Elise, something after 25 years of ownership I still have to pinch myself over and the Norton will no doubt never elude either.

Simon
Click to expand...
Cafe man! You’re killing me here!
Truly a fun read, and I’m so very happy for you mate!
I can’t wait for my little joy ride planned for tomorrow, and my rides to work Monday and Tuesday next week.
 
Café au Lait said:
Managed to take advance some nice weather today and have a fairly short ride to compare a couple of mirror choices and to test the outstanding idle issue.

From cold the bike ran flawlessly and I even managed to only have one false neutral (usually pretty common for me changing down from 4th to 3rd) when I forgot to be more positive than I’m used to with the Kawasaki W.

Overall an excellent ride albeit short, just flowed nicely and allowed me to fully engage with the bike’s personality which it has in volumes; rolling on with this bike is soooo addictive.

I also tested the Auto Meter speedo for accuracy (thanks RobSS for the tip) with an GPS IOS app and it’s bang on meaning Matt did an excellent job of calibrating it. And also thanks to RobSS for the tip of fitting a Paul Goff Daylighter 2 LED headlight bulb, super bright with excellent high/low beam pattern.
Matt did warn me of the bikes potential thirst with these FCR 35s but I’ve filled 3 times and achieved 55-57mpg even with some spirited riding so no complaints:); I was fearing sub 40 or worse 😫
Click to expand...
I’m curious about this Paul Goff Daylighter 2 LED headlight bulb. Never heard of it and who wouldn’t want excellent light and beam pattern?
Cafe man, can you tell me more about this marvel and where one might acquire it?
 
Starvingphotog said:
I’m curious about this Paul Goff Daylighter 2 LED headlight bulb. Never heard of it and who wouldn’t want excellent light and beam pattern?
Cafe man, can you tell me more about this marvel and where one might acquire it?
Click to expand...
Highly recommended to me by RobbSS and his recommendation was well founded, bright with correct pattern unlike others I’ve tried.

LED Headlight bulbs British Pre-Focus + H4s

Double Dipper, British Pre Focus LEDs, Stop tail LEDs, LED H4 car headlights, LED headlight bulbs,LED H4, H4 LED,British Pre Focus LED,Bayonet Cap LED, LED headlamp bulbs,H4 LED headlamp bulbs,LED headlights for old bikes,LED headlights for old cars
www.norbsa02.freeuk.com
 
The Halcyon mirrors are well made, but the left mirror fouls the clutch lever on my Mk3, unless it is pulled out from the bar end by approx 1/2".
 
Mart UK said:
The Halcyon mirrors are well made, but the left mirror fouls the clutch lever on my Mk3, unless it is pulled out from the bar end by approx 1/2".
Click to expand...
Shifting the pivot bracket in-board a bit wouldn't work?
That's what I did with Matt's hydraulic clutch lever.
 
Mart UK said:
No room. The bend in the bar prevents it.
Click to expand...
My bars are 765mm wide and have 5mm clearance on each mirror. I can move the lever pivots another 12mm inboard if needed.
I suppose it comes down to bar width and where your bends are.
Cheers
 
Another problem free ride yesterday, fingers crossed the erratic idle issue is over, maybe just needed some use after months of being laid up.

My gear selector rubber failed yesterday so I’ll add a couple to my Andover Norton order. Whilst I’m about it are there any necessary special tools for regular maintenance bar the sump filter spanner I need to buy?Are AN a good source for oil filters or do you guys (U.K.) have preferences?
 
Café au Lait said:
Another problem free ride yesterday, fingers crossed the erratic idle issue is over, maybe just needed some use after months of being laid up.

My gear selector rubber failed yesterday so I’ll add a couple to my Andover Norton order. Whilst I’m about it are there any necessary special tools for regular maintenance bar the sump filter spanner I need to buy?Are AN a good source for oil filters or do you guys (U.K.) have preferences?
Click to expand...
Just check the oil filter - mine from Matt is not standard Norton fare.
Ended up finding a match here (in Australia) - Ryco Z418. Good news is that they're available in most of the car accessory shops.
Cheers
 
Right on the oil filter. I got one of those thread inserts from Matt to convert my filter to a standard size spin on to accept common filter sizes available in America.
Here is a link to the filter adapter from Matt, and an image of the filters that I now use on the Norton as per Matt's recommendations for the Norton engine.

coloradonortonworks.net

cNw Oil Filter Adaptor

Changes the threads on your oil filter housing Simple installation in minutes Allows use of readily available modern oil filters Kit includes an oil filter and a list of filters that can be used
coloradonortonworks.net coloradonortonworks.net


cNw #101 Norton Commando 850
 
Having a cNw build I assume I have that adaptor fitted, I guess I’ll find out come the time. I was actually asking more specifically which brand of filter as my understanding they vary quite a bit in quality and some worth avoiding. Obviously if AN supplied filters are right up with the best I’ll just add a few to my cart with the other bits; just tapping into the knowledge base :)
 

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