Easy and cheap modifications I would do again

Peter Restaino said:

Very detailed explanation. Now I really dont what to do. Only fooling kinda. So I understand that the stock breather port on the 70 case is to small by itself to handle the flow of air so adding a second teed in at the right rear will do the trick. does that mean a reed valve at both locations. thanks

Click to expand...

This is my reed valve teed to the rotary disc valve

Peter Restaino said:

Very detailed explanation. Now I really dont what to do. Only fooling kinda. So I understand that the stock breather port on the 70 case is to small by itself to handle the flow of air so adding a second teed in at the right rear will do the trick. does that mean a reed valve at both locations. thanks

Click to expand...

Back in the day, a certain mechanic I know used to claim that his bikes didn't leak. Implying that other people working on parallel twins were less competent. Once the whole reed breather design was applied to commandos it became pretty easy to have a nearly leak proof bike, and that's probably the best reason to consider spending some money on the best reed breather solution you can afford. In the end, having a somewhat clean, leakproof bike helps you in a lot of ways.

The original sump plug breather design of Jim Comstock didn't fit on the early frame bikes because a cross member blocked the body of his mechanism. That's why you see people like me and a few others who have more home made designs. It's not that the home made designs don't work ok, but the sump plug design also pumps out the oil that sumps in the crankcase when the bike sits without being ridden for a while..... Jim Schmidt developed a sump plug breather that fits our early bikes, long after I did my own modification and since I am not leaking anywhere, I'm sticking with what I have... HTH

When a motor is running, it probably does not matter what size the crank-case breather is, it always needs a PC valve. I use one from a Ford Falcon motor car. On road-racing motorcycles in Australia, we always have catch-tank at the end of the breather which probably stops the PC valve from working. A lot of oil leaks on road bikes are probably caused by blow-by past the piston rings. When a tight motor is running and has a large diameter clear plastic breather pipe, the oil usually stays stationary inside it.

Cheapest thing I've done to my 750 engine that made a positive difference is the JSM offset stepped cam key set up for 2 degrees of cam timing advance. ($6.00US, plus owner labor) The JS2 cam I'm using it with wasn't that cheap though. What the 2 additional degrees of cam timing did was improve the torque/power curve making it very linier and better on the street. It was already good, but it is better now. I don't know if it made any difference at high RPM. I have not been over 90mph with my current engine set up. My engine doesn't struggle at all to hit 90 mph. Theoretically HP might drop off sooner at high RPM, since it comes on sooner with advanced cam timing. Not sure if 2 more degrees of cam timing would be very noticeable with a stock cam, but it would work with a 2S cam which I found to be a little spikey in power delivery.

I did not do before and after dyno runs on the same dyno to get any numbers. 2 degrees is not much, but I don't know if it would work with totally flat top pistons without valve pockets. My guess is it would but should be verified.

The change 2 degrees of additional cam timing makes might be too subtle for some people, making it a waste of their time, and might be too much work for a lot of people that have never seen what is behind the timing side cover. YBDMV

There are many, but these are some examples…

Replaced the OEM master cylinder (with the Brembo (and OEM switchgear adapter) from CNW, added SS brake lines and Ferodo platinum pads to get "current motorcycle" brake performance from the Commando (absent ABS, of course!.

Re brakes: In my experience an aftermarket sleeved OEM MC is a safety hazard, having had two fail. One failed overnight in the garage, the other failed out on the road between stoplights!

Trispark ignition. Had a Boyer when I bought the bike, converted it back to OEM points to restore OEM low/midrange performance. Switched to Trispark shortly after it was released for it's duplication of the OEM advance curve.

CNW 520 sealed chain conversion

Reed type crankcase breather

Alton E Start

Pair of Amal Premiers

People will make silly, long, lists of mods, many of which are not really necessary.

There are only 3 mods you must do:

1) TTI gearbox
2) 1007 engine
3) Seeley chassis

The rest is just details.

Great Mods, FE. But do you remove the "Commando" stickers since it is no longer a Norton Commando?

IMO the ONLY mod that is really essential for riding a Commando in modern traffic is better braking performance. The rest is personal preference for convenience, reduced maintenance, or appearance! With better brakes, an otherwise totally stock Commando in proper operating condition can function just fine in current traffic environments - anything from bumper to bumper stuff up to cruising on Interstate/M roads. Though the horn honking in the bumper to bumper stuff can be a bit annoying if you stall your pre-Mk3 on occasion.

Schwany said:

Cheapest thing I've done to my 750 engine that made a positive difference is the JSM offset stepped cam key set up for 2 degrees of cam timing advance. ($6.00US, plus owner labor) The JS2 cam I'm using it with wasn't that cheap though. What the 2 additional degrees of cam timing did was improve the torque/power curve making it very linier and better on the street. It was already good, but it is better now. I don't know if it made any difference at high RPM. I have not been over 90mph with my current engine set up. My engine doesn't struggle at all to hit 90 mph. Theoretically HP might drop off sooner at high RPM, since it comes on sooner with advanced cam timing. Not sure if 2 more degrees of cam timing would be very noticeable with a stock cam, but it would work with a 2S cam which I found to be a little spikey in power delivery.

I did not do before and after dyno runs on the same dyno to get any numbers. 2 degrees is not much, but I don't know if it would work with totally flat top pistons without valve pockets. My guess is it would but should be verified.

The change 2 degrees of additional cam timing makes might be too subtle for some people, making it a waste of their time, and might be too much work for a lot of people that have never seen what is behind the timing side cover. YBDMV

Click to expand...

It is normal when seeking performance, to adjust the cam timing and jetting to suit the exhaust system and the way the bike is intended to be used. A two into one exhaust system responds well when a Commando cam is advanced 6 degrees. Mine is advanced 12 degrees - is good but too loud. The resonance of the exhaust system can be used to increased power, but there is usually a downside. Fitting megaphone exhausts to a well tuned motor can cause jetting to be too lean. A two into one exhaust can need leaner jetting.
It can be deceptive - increasing comp. ratio or increasing ignition advance, also has a leaning-off effect. So only change one thing at a time while making sure you don't burn pistons or valves.
Some people seem to believe the exhaust system is only about gas flow. Kadence effect also happens in four-stroke motors. -

Actual low cost improvements:
Zip tie to keep the left side cover arm on my Mark III in place. With the zip tie, the twist fastener stays in place. Locktite Blue, applied liberally to nuts and bolts. Duluth Trading Company heavy duty toiletries kit, bungee corded to Craven rack on back of bike (Craven rack came with bike) securely holds several pounds of tools.

nortonmargie said:

Actual low cost improvements:
Zip tie to keep the left side cover arm on my Mark III in place. With the zip tie, the twist fastener stays in place. Locktite Blue, applied liberally to nuts and bolts. Duluth Trading Company heavy duty toiletries kit, bungee corded to Craven rack on back of bike (Craven rack came with bike) securely holds several pounds of tools.

Click to expand...

It's interesting about the loctite comment. I have seen others say the same but with the exception of the rear indicator lights on the long stalks I can't recall a single nut or bolt come loose in coming on 48 years.

The indicator units are made of plastic so you can't tighten very firmly. Plus there is very little clearance for a spanner. But once you find a suitable slimmed down spanner I find even they behave themselves.

I will admit to one stripped bolt into a slider for the front mudguard.

They say hard mount Nortons vibrate a lot and lose lots of things from falling off, well in over 44+ years with my 850 Commando motor mounted in the Featherbed frame I have only lost one rear muffler nut on the bracket, the bolt was still there and the top gearbox mounting nut, I don't use loctite on my nuts and bolts but I do use spring washers on every nut and bolts, so not bad for a bike that everyone says it will shake your teeth out, I had more problems loosing things with the 4 years of owning my Norton new when it was mounted in the Commando frame, seems to shake more rubber mounted, my header pipes have no locking rings at all and the flangers always stay tight so no flogged out flange threads.
But I have a good collection of spring washers, so any nuts and bolts undone I always replace the spring washers with new ones and all my engine mounting bolts are all fine threads, well most of my nuts and bolts are, I am still using all the original motor bolts to the engine mounts as well on my motor, but my crank was balanced for the Featherbed frame way back in 1981.
But I read a lot about things falling off Commando frames with isolastics mounts and I think there is an old threat on here somewhere on the subject in what has fallen off our Commando's, but it's all part of general maintenance to go over our bikes looking for things that come lose, something I don't do myself well not very often anyway, by the way I lost my original horn that I had mounted under my frame, the bracket is still there but the horn is on the Bruce hwy somewhere, that was 10 years ago lol.

Ashley

I never understood lock washers. Once any significant amount of torque is applied, they can't be doing anything with that tiny spring pressure. I think the only benefit is to buffer the mating area and a flat washer is just as good at that. NASA did tests on them, supposedly (could be an Urban legend I admit) that said they are dead weight. Just a different viewpoint. I put them on according to the diagrams, regardless. Gimme Loctite blue (or red for crank/rod area) or a nylock any time, if it's something critical that I have concerns about. I rebuilt an N15CS 'hard mount', and it's got 1200 miles on it after a total rebuild. There have been zero loose or missing fasteners so far. One loose nut behind the bars though!

Anyway, not like it will have wide applicability, but here's an easy and cheap mod: I needed an MC for the disc brake I threw on my N15. I didn't want that big honkin' Lockheed one anywhere near my bike, and wow, big $$$ to get a decent one anyway. I looked at bore sizes and found that a Yaaha Riva scooter has a 12mm bore, and brake switch - originally my bike had none. $15 on eBay brought me a perfect example. I filled the 'Yamaha' with JB weld and painted over it, nobody's the wiser! With the Commando disc, Ferodo pads, and aftermarket drilled disc the bike stops fantastic. Total cost under $300 but I had some 'gifting' of fork lowers and the caliper etc.

gpzkat said:

I never understood lock washers. Once any significant amount of torque is applied, they can't be doing anything with that tiny spring pressure. I think the only benefit is to buffer the mating area and a flat washer is just as good at that. NASA did tests on them, supposedly (could be an Urban legend I admit) that said they are dead weight. Just a different viewpoint. I put them on according to the diagrams, regardless. Gimme Loctite blue (or red for crank/rod area) or a nylock any time, if it's something critical that I have concerns about. I rebuilt an N15CS 'hard mount', and it's got 1200 miles on it after a total rebuild. There have been zero loose or missing fasteners so far. One loose nut behind the bars though!

Click to expand...

The thing that makes lock washers (split washers) work at all is what I don't like about them. As you said, the flattening does little to nothing. But if properly made, there are two sharp edges that prevent the nut from loosening or stop it from continuing to loosen. These edges also cut into the underlying surface and the surface of the nut. Generally, once unscrewed, they need to be replaced as those sharp edges are gone.

Today, the only split washers I use are on AMAL carbs - unscrew the screws from a new set of carbs and you'll see the effect of the washer cutting into the metal. I mostly use NyLock nuts and Blue Locktite when installing studs or bolts into treaded holes and I never add washers to things designed without them such as conrod nuts.

marshg246 said:

The thing that makes lock washers (split washers) work at all is what I don't like about them. As you said, the flattening does little to nothing. But if properly made, there are two sharp edges that prevent the nut from loosening or stop it from continuing to loosen. These edges also cut into the underlying surface and the surface of the nut. Generally, once unscrewed, they need to be replaced as those sharp edges are gone.

Click to expand...

Very interesting, had not thought of that. Not that I have thought about it that much TBH. But I'm gonna pull out my cool LED lighted magnifying glasses (with multiple magnifying lenses) and see if I find any witness marks on some bits I have that are absolutely as-is from the factory.

The thinking that split ring lock washers DON"T work is faulty.

Let's see...they don't work but despite that have been used extensively for many, MANY years in all sorts of machinery?.
Nope, they work as designed. Of course, that doesn't mean that using them in every application is the correct use - that's why there are other types of locking mechanisms and fluids

The only reason a lock washer (or loctite) is ever needed is if the fitting is not tightened to the tension for optimum stretch of the screw/bolt. If the bolt is correctly "stretched" no locking device of any type is required - it locks itself. A torque wrench/specs is supposed to accomplish this but is subject to considerable variation in use. Torque-to-yield bolts are a much more positive way to achieve the optimum results. Of course, in daily use, many bolts cannot be tightened to that optimum stretch for a variety of reasons so locking "devices" are installed to prevent self loosening.

In the several shops I worked with, split ring lock washers were never reused in critical fittings.

Half the time I'll put a lock washer in the vice and with a twist they're now small O.D. flat washers. A common spot is the carb flange studs. In this spot I also use 5/16 half nuts (jam nuts) for more room.

johnm said:

It's interesting about the loctite comment. I have seen others say the same but with the exception of the rear indicator lights on the long stalks I can't recall a single nut or bolt come loose in coming on 48 years.

The indicator units are made of plastic so you can't tighten very firmly. Plus there is very little clearance for a spanner. But once you find a suitable slimmed down spanner I find even they behave themselves.

I will admit to one stripped bolt into a slider for the front mudguard.

Click to expand...

I should add that I do use loctite on the clutch adjustment lock nut and gearbox sprocket locknut and screw. Places like rear shock mounts and tank nuts are nylock as well.

acotrel said:

It is normal when seeking performance, to adjust the cam timing and jetting to suit the exhaust system and the way the bike is intended to be used. A two into one exhaust system responds well when a Commando cam is advanced 6 degrees. Mine is advanced 12 degrees - is good but too loud. The resonance of the exhaust system can be used to increased power, but there is usually a downside. Fitting megaphone exhausts to a well tuned motor can cause jetting to be too lean. A two into one exhaust can need leaner jetting.
It can be deceptive - increasing comp. ratio or increasing ignition advance, also has a leaning-off effect. So only change one thing at a time while making sure you don't burn pistons or valves.
Some people seem to believe the exhaust system is only about gas flow. Kadence effect also happens in four-stroke motors. - ]

Click to expand...

Okay spanky.

What I've done works well enough. I don't over analyze anything. I'm on autopilot when tuning and do what needs to be done.

I was going to do 3 degrees, but Jim said try 2 degrees first. I think his JS2 cam has some advance ground into it. Guess work on my part though.

Nobody would believe how well all the stuff I've done to my Norton works now. I wish I were 30 years younger and could use it all like it should be used. Best I can do is pretend like I'm using it like it should be used. Still brings some joy when I twist the throttle. That is what counts for me.

Schwany said:

Okay spanky.

What I've done works well enough. I don't over analyze anything. I'm on autopilot when tuning and do what needs to be done.

I was going to do 3 degrees, but Jim said try 2 degrees first. I think his JS2 cam has some advance ground into it. Guess work on my part though.

Nobody would believe how well all the stuff I've done to my Norton works now. I wish I were 30 years younger and could use it all like it should be used. Best I can do is pretend like I'm using it like it should be used. Still brings some joy when I twist the throttle. That is what counts for me.

Click to expand...

Be glad that you don't use it like it could be used... at 70-ish years old. Although I heard the hospital serves jello for desert