Exhaust questions

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:? Hi
This is my first post here, but with the recent purchase of a 69 Commando, it won't be the last. This is my first Norton, I have had Triumphs in the past, so I've tried to read up and get smart on Nortons but it seems that the more I research and read, the more confusing some things become. Therefore I'd like to ask for recommendations from people who actually know something about them.
The bike is a 69 with a little over 3200 mi on the clock, pretty much all there and not in too bad a condition (I think). The engine is stamped 20M3S/1330xx. Does this indicate a model? I was told that the bike may have been an S model (I guess those are the ones with the scrambler type high mount exhaust). As it no longer really has an exhaust system(and no sign of mounts) I can't tell. Perhaps if it was an S that would explain the Dunlop K70s on both ends and the little grill around the headlight. As I said it really doesn't have an exhaust so that's where I need to start, and I need the whole system including the nuts on the head. I plan to use it for road work, mainly spirited solo touring so I would like to get the best performance (read least restriction) from it, but I would also like an easy fit with the standard kick lever, etc.. I have seen replacement S model systems and would consider that but would like to know what the advantages/disadvantages are as the price a bit higher. I noted quite a discussion in a recent thread about problems with kick starts hitting the mufflers and would like to avoid that sort of thing. What I would really like is recommendations on specific systems (brands) that would meet my needs for fit and performance. Is it necessary to buy a complete set from one manufacturer or is it possible to mix pipes, mufflers, mounts, nuts? Also, I have read differing ideas on the exhaust nuts, like using newer 850 nuts for more security. What is the preferred setup here ?
The carbs seem to be in reasonable working order (the least worn set of Amals I've seen) and after a good cleaning internally, I will continue to use them. The set up is: mains, 320; needle jets, 106; needles, 2 groove using top notch for clip; and #3 slide. It does not appear that anyone has changed them but I am unsure what the factory specs were.
There are obviously other things to check, renew or replace, like the tires, but I'd like to get the exhaust fixed first, so I would appreciate all comments on what to get. Thank you again for your input.

Cheers
 
Welcome to the forum sidreilley,

sidreilley said:
The engine is stamped 20M3S/1330xx. Does this indicate a model? I was told that the bike may have been an S model (I guess those are the ones with the scrambler type high mount exhaust).

The prefix and serial number does appear to be within the 750 'S' production series.

Early Roadsters also had the headlamp ring (and central oil tank) but the serial number is too low for it to be a Roadster. the serial number is also too low to be a 20M3S version Fastback.


sidreilley said:
As I said it really doesn't have an exhaust so that's where I need to start, and I need the whole system including the nuts on the head. I plan to use it for road work, mainly spirited solo touring so I would like to get the best performance (read least restriction) from it, but I would also like an easy fit with the standard kick lever, etc.. I have seen replacement S model systems and would consider that but would like to know what the advantages/disadvantages are as the price a bit higher.

Performance-wise there's probably little to choose between the S and Roadster systems? The S system has a few more parts to it, so it could be a bit more expensive?

Viking are just about the best quality exhaust systems but are also more expensive. Toga are good quality, although what system you eventually buy could depend on whereabouts in the world you live, [Edit: I now see you have added that information to your profile] and who your parts suppliers are?


sidreilley said:
I noted quite a discussion in a recent thread about problems with kick starts hitting the mufflers and would like to avoid that sort of thing.

If you decided on the S system, then you are not going to have any kickstart lever fouling problems.

sidreilley said:
Is it necessary to buy a complete set from one manufacturer or is it possible to mix pipes, mufflers, mounts, nuts?

I'd say that if you were to buy the whole system from a single supplier then there can't be any arguments over who's parts are faulty if things don't fit together properly?

sidreilley said:
Also, I have read differing ideas on the exhaust nuts, like using newer 850 nuts for more security. What is the preferred setup here ?

The bronze nuts stay tight.

sidreilley said:
The carbs seem to be in reasonable working order (the least worn set of Amals I've seen) and after a good cleaning internally, I will continue to use them. The set up is: mains, 320; needle jets, 106; needles, 2 groove using top notch for clip; and #3 slide. It does not appear that anyone has changed them but I am unsure what the factory specs were.

Mains should be 220, not 320?

The "S" & early Roadster model riders manual lists the needle jets as .107, with needles in the middle groove, however this appears to conflict with other information that lists a .106 needle jet?
 
I have a '74 850 Roadster that I'm restoring and have been looking around for a new exhaust system. I see that Commando Specialties has a complete system for $270 (http://www.commandospecialties.com/Prod ... ?MSecID=53). Given the price I'm guessing that it's an inferior system. Has anyone out there tried this system and is it worth considering? I also note that they have a complete "S" system for $559 in case sidreilley wants to take a look.

Thanks,

Jim Malm
 

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sidreilley said:
SNIP the nuts on the head. SNIP

This is the easy part:

Get Bronze nuts (Norvil).

Tighten them (with no lockwasher/safety wire or anything).

Warm up the bike real well and tighten them again.

You are good to go, the expansion/contraction rate for Bronze is so
close to the rate of the head that they will stay tight.

As far as CS products, while I have no personal experience I've never
heard anything bad about them.

Unclviny
 
I have purchased an s type exhaust system from commando specialties and am very pleased with the product and purchase price was cheaper than what was stated on this post, mufflers are manufactered by wassel not sure about the rest of the system though i have not mounted it yet as bike is not ready for it. Evan though viking is New Zealand made it was considerably cheaper to buy from commando specialties in USA.
 
Many thanks for the replies!
Glad to know about the bronze exhaust nuts, I didn't know they existed! An easy fix when I get the old ones off.

I had seen the Commando Specialties systems, but given the "reasonable" price, I was unsure about the quality and fit issues so I was hoping to hear from someone who was using their stuff. I had been told that the mounts and clamps were important (to get quality items) and was unsure what that meant (and who made it). Came across a Bub system (2 into 1) also. It looks to be high quality and would solve some problems but don't know about the look. I am also undecided if I like the look of the S system over the standard, and wondered if there were any trade offs.

Would like to replace what's necessary and upgrade a few things (tires, ignition) and ride it for a few years before doing and major dis-assembly /renovation work. I plan to stay pretty close to stock so it's nice to know what it came out of the factory looking like. I didn't realize the were so many variations of Commando.

Nice to know the stock jetting too so I know where to begin. 320 seemed large but I am only familiar with Triumphs. It didn't look like anyone had been into the carbs, but the previous owner may have changed mains as a simplistic fix to compensate for the system that's on it now. It appears to have Triumph TT pipes ending in foot-long chrome tubes that belong on a lawn mower! Can't be much back pressure there. The bike hasn't been on the road since 1975.

I'm getting the (glassfibre) tank sealed first off, then the exhaust, air filter, add battery and see if it starts! :)
 
sidreilley said:
Nice to know the stock jetting too so I know where to begin. 320 seemed large but I am only familiar with Triumphs.


On the Britbike website you mentioned "230" mains, so do you actually mean 230 and not 320? As 220/230 would be normal, but 320 main jets would be far too rich?
 
I have a 69 S in fireflake blue, have had it since about 71(20M3S132031). At about 8K miles, the heatshields cracked and I removed them. The L bracket finally got a crack and I got a 2 to 1 Hooker setup. What a mess. The Hooker scraped on the ground. Got rid of that and went on to regular roadster exhausts and peashooters. I do like the look of the S pipes personally, but I think the roadster setup is more stable. I am restoring mine with the original S pipes since I will be putting minimal mileage on it. I got a set of exhaust from Xanders (now gone) and a set of silencers from Walridge. Walridge used to have good prices about a year ago because you could get a 20% discount because of the exchange rate, not now. I have a modified setup instructions for installing the S pipes that may hold up better. If you want it, I can look it up. Walridge also sells a sealed double row bearing for the front and rear hubs if you are interested. No machining of the hubs for new sealed bearings like on old britts.

Sealing the f/g seems to be a hit or miss project. Some have had luck, others not. In any case, I would not leave ethanol in it for a long time. I plan on looking for non ethanol gas, maybe at the local airport, but am not holding my breath. I wonder what the boat people do that have f/g tanks?

Dave
69 S project
 
LAB - Did I mention the I'm dyslexic if I stare at a computer screen too long? I did mean 230.

Dave - Thanks for your experiences with the S pipes. I had a feeling that there might be some issues in getting a solid mount. Given the extra cost of the S system, I'm leaning to the roadster set up from C/S or possibly the BUB 2-1. Sounds like Hooker isn't the way to go! I think RGM lists a 2-1 at a reasonable price, has anyone tried it? Oh, I am interested in the sealed wheel bearings. It wasn't on my short list of things to do because I thought it would require machining.
 
sidreilley
I see you are in Madison, we can see Old Rag Mt. from Hume on a clear day.

Dave
 
Dave, I can see Rag too but it's hard to recognize it from this angle. :wink: We should get together some day, I'd like to see your S and hear what it's like to have a Norton since 71! Actually, weather is supposed to be nice tomorrow, I may ride up as far as Sperryville anyway for an ice cream in the afternoon. Shoot me a P/M if you're interested.

Cheers
 
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