So many new upgrades available these days

Peter Williams found his 2S design to be wanting in the midrange and quite harsh on the valve train, so it's not a cam I would go for in a (hopefully) long lived road engine aimed for lots of midrange torque.
I have tested this 920 against the 850 on Dyno hill. The 850 managed to accelerate from 100 to 113 kmh whereas the 920 accelerates from 100 to 135 kmh.
The 920 is a lot lighter but my sense is that about half of that performance gain is from the 920 and the other half is from the weight difference.
One day I'll add ballast to the 920 and do the test.
 
I don't know but in 1980 I built my motor for the Featherbed frame and hard mounts,I went with a 2S cam grind for better midrange performance with my crank balanced at 72% I am running my stock valves still and all the ports have been open up for smooth fuel deliveries and new valve springs as well guides, as well the head was shaved the carbs jetted for my motor and open exhaust system.
Performance wise it's so much better than stock, my stock motor would never rev higher than 6500 RPMs as it would valve bounce and lose power, with the 2S cam grind made a big difference without over doing it, you can feel the cam kick in around 4/4500 RPMs and gets its best performance from there to 7000 RPMs but you got to watch out as it will rev freely past that but why would you.
In 40 years of riding my hot Norton you know when best to change up without over stressing the motor and my motor no longer valve bounce at all it will keep reving.
I still run flat top pistons 40th oversize Hepolite pistons the rebore was done at tight tolerances between the final bore and hone, under what was recondmended and the first run was at 3 am on a very cold winter night to clock up the first 100 miles,
( I froze my balls that night) to this day I am still running these pistons although with new rings and light hone when I replaced cracked crank case and a broken front crank where the front stud broke away and was rolling around on top of my crank for a few years, at idle it rattled but as soon as the revs came up it flowed between the barrels, I just glued the stud in place.
You might not believe me but when I pulled that motor down to replace the crank cases that broken piece was like a polished jem stone it just stayed in place between the top of the crank and inbetween the barrels, I still have that broken piece somewhere in my bits.
From 1982 right through to to 2013 my Norton was a everyday rider except for a few upgrades in between, all the internal are the same just the crank cases were change, forget what year that was, all up from new my motor has well over 160K miles on it and about 140K miles while in the Featherbed frame, I average between 6k to 10k miles a year for most of its life was a everyday rider with a few breaks in between, it had a few years break while I was hunting up replacement crank cases but I had my 81 Triumph Thunderbird as well at the time as I have always had a bike on the road.
From 2013 my Norton is semi retired but I still ride it regularly my Thruxton is my go out and travel bike now, my Norton is my play bike now.
My point with this you can build a lightly hot motor without over doing it and for me the 2S cam works great for that extra midrange and the rest of what's been done to make it breath and to get the burnt gases out quickly + my Commando/Featherbed is a light weight bike and have cut back a lot of weight compared to the Commando, it's built for handling, lightness, torque and reliability and what I done has prove itself in the 40 when I first built it and the last 14 years with the upgrades I have done it's even better.
I don't care if it's not the fastest around but I built it for my riding style, for reliability and great handling, it surprises a lot of modern bike and is very quick off the mark, it's my play bike and is so much fun compared to what it use to be when in the Commando frame, it's shorter and a lot lighter in everything.
Also the motor can be run around town and suburbs at 40 MPH in top gear and it be smooth but under that have to drop it down a gear, the crank balance has done its job, yes I do get some vibrations at certain revs but it always smoothes out.

Ashley
 
All this hen pecking and bickering is futile. And frankly, very tiresome.

There is NO right or wrong.

There is no discussion about ‘need’ … frankly we don’t ‘need’ any of this shit, not even a standard Norton !

What we ‘want’ is a different matter entirely.

And that is infinitely variable based on our own individual desires.

No one can tell anyone else that they are ‘wrong’ with regards to decisions they make about their lifestyle choices.

You want a standard Norton? Go for it.

You want a hot rod? Go for it.

You want to fit a supercharger? Hell yeah, go for it !

You wanna ride around at 3,000rpm and do 200,000 miles without a rebore? Go for it.

You wanna blow off the ‘corner cripples‘ on ‘the’ gravel? Go for it Hobot !

It’s none of anyone else’s freakin’ business…
 
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Not really. As soon as you post about it on t'internet you make it somebody else's business.

Thought it was mostly good natured virtual pub banter. Not even 'handbags at dawn'. :) 👍

What's interesting is how many different uses and riding styles the Commando platform can support.
 
ashman said:
I don't know but in 1980 I built my motor for the Featherbed frame and hard mounts,I went with a 2S cam grind for better midrange performance with my crank balanced at 72% I am running my stock valves still and all the ports have been open up for smooth fuel deliveries and new valve springs as well guides, as well the head was shaved the carbs jetted for my motor and open exhaust system.
Performance wise it's so much better than stock, my stock motor would never rev higher than 6500 RPMs as it would valve bounce and lose power, with the 2S cam grind made a big difference without over doing it, you can feel the cam kick in around 4/4500 RPMs and gets its best performance from there to 7000 RPMs but you got to watch out as it will rev freely past that but why would you.
In 40 years of riding my hot Norton you know when best to change up without over stressing the motor and my motor no longer valve bounce at all it will keep reving.
I still run flat top pistons 40th oversize Hepolite pistons the rebore was done at tight tolerances between the final bore and hone, under what was recondmended and the first run was at 3 am on a very cold winter night to clock up the first 100 miles,
( I froze my balls that night) to this day I am still running these pistons although with new rings and light hone when I replaced cracked crank case and a broken front crank where the front stud broke away and was rolling around on top of my crank for a few years, at idle it rattled but as soon as the revs came up it flowed between the barrels, I just glued the stud in place.
You might not believe me but when I pulled that motor down to replace the crank cases that broken piece was like a polished jem stone it just stayed in place between the top of the crank and inbetween the barrels, I still have that broken piece somewhere in my bits.
From 1982 right through to to 2013 my Norton was a everyday rider except for a few upgrades in between, all the internal are the same just the crank cases were change, forget what year that was, all up from new my motor has well over 160K miles on it and about 140K miles while in the Featherbed frame, I average between 6k to 10k miles a year for most of its life was a everyday rider with a few breaks in between, it had a few years break while I was hunting up replacement crank cases but I had my 81 Triumph Thunderbird as well at the time as I have always had a bike on the road.
From 2013 my Norton is semi retired but I still ride it regularly my Thruxton is my go out and travel bike now, my Norton is my play bike now.
My point with this you can build a lightly hot motor without over doing it and for me the 2S cam works great for that extra midrange and the rest of what's been done to make it breath and to get the burnt gases out quickly + my Commando/Featherbed is a light weight bike and have cut back a lot of weight compared to the Commando, it's built for handling, lightness, torque and reliability and what I done has prove itself in the 40 when I first built it and the last 14 years with the upgrades I have done it's even better.
I don't care if it's not the fastest around but I built it for my riding style, for reliability and great handling, it surprises a lot of modern bike and is very quick off the mark, it's my play bike and is so much fun compared to what it use to be when in the Commando frame, it's shorter and a lot lighter in everything.
Also the motor can be run around town and suburbs at 40 MPH in top gear and it be smooth but under that have to drop it down a gear, the crank balance has done its job, yes I do get some vibrations at certain revs but it always smoothes out.

Ashley
Click to expand...
How is the appetite for valve springs with the 2s cam ?
I've seen combats with worn out /broken valve springs not lasting much more than 20,000 miles
 
Baz the same springs are in my motor when the head was done up back in the 80s when I built the motor for the Featherbed and so far still hanging in there
but it's been some time since the head has been off when I replaced the crank cases, the valves were pulled out and springs show no sign of any problems, when I built this motor the new spring weren't stock springs, but I can't remember as so long ago, new guides were put in when the crank cases were replaced, new rings and the lifters were reground on a surface grinder at work, new bearing through out for the replacement cases.
I have a freak motor it's just been so good to me.
 
Group hug

I think everything I do is the right thing to do, cuz I'm doing it for myself, not because anyone else is doing it.

Check out that Formula 1 Drive to Survive series that came out 02/24/2023 on Netflix. It's fun to see what the guys with real money are up to in motorsports.
 
One more flick of the whip on the dead horse.

The 2S or SS is a violent cam, but it worked well in my straight up motor. It does lack some torque at low RPM, but shifting up at 2000 RPM isn't what it was designed for. Lot of fun if the revs are kept up. Of course one man's fun is another man's unsafe foolishness. The 2S didn't self-destruct in my 750, but there is evidence of wear on the valve stem tips and tappets.

A cam with similar performance but more usable street torque is the JSM JS2SS. Other cams probably work just as well if the stock profile is not what you are after.

I can't remember what the stock cam in my P11 was like, but it must have been alright. I thought I had a quick bike in the straights until the Z1 came out. lol
 
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baz said:
How is the appetite for valve springs with the 2s cam ?
I've seen combats with worn out /broken valve springs not lasting much more than 20,000 miles
Click to expand...
Yor missing the point Baz… simply change your valve springs every second main bearing change and you’ll be fine … ;)
 
Fast Eddie said:
All this hen pecking and bickering is futile. And frankly, very tiresome.

There is NO right or wrong.

There is no discussion about ‘need’ … frankly we don’t ‘need’ any of this shit, not even a standard Norton !

What we ‘want’ is a different matter entirely.

And that is infinitely variable based on our own individual desires.

No one can tell anyone else that they are ‘wrong’ with regards to decisions they make about their lifestyle choices.

You want a standard Norton? Go for it.

You want a hot rod? Go for it.

You want to fit a supercharger? Hell yeah, go for it !

You wanna ride around at 3,000rpm and do 200,000 miles without a rebore? Go for it.

You wanna blow off the ‘corner cripples‘ on ‘the’ gravel? Go for it Hobot !

It’s none of anyone else’s freakin’ business…
Click to expand...
I thought it was just a discussion about modifications, what works and what doesn't.
Could be helpful for newcomers.

Glen
 
worntorn said:
I thought it was just a discussion about modifications, what works and what doesn't.
Could be helpful for newcomers.

Glen
Click to expand...
Your definition of what works and what doesn’t seems very skewed IMHO almost going as far as saying any and all engine modifications are wrong unless you build an all new motor !
 
I certainly didn't think that way 20 years ago when I bought the Commando. I immediately ran out and purchased a 920 kit. A hot cam, big carbs, port work and highcompression were in the plans too.
Then I started reading both in books and in forums. I also rode the stock bike quite a lot and realized that it had very good power for road use here in mountainous BC.

As time and these bike wear on, the stock or near stock engine does seem to be best for longevity.
In a way , they are a funny bike. Try to use them a bit beyond their intended power levels (Dreer 880) and it doesn't work.
Run them fairly hard at the lower level and they will almost run forever.
With the occasional rebuild added they will run forever.

Glen
 
On a track, for sure.
Funny thing, when out on the roads on the Commando it seems to really cover the ground. There aren't many going past and often those that do will get caught up on the twisty stuff.


Glen
 
worntorn said:
I certainly didn't think that way 20 years ago when I bought the Commando. I immediately ran out and purchased a 920 kit. A hot cam, big carbs, port work and highcompression were in the plans too.
Then I started reading both in books and in forums. I also rode the stock bike quite a lot and realized that it had very good power for road use here in mountainous BC.

As time and these bike wear on, the stock or near stock engine does seem to be best for longevity.
In a way , they are a funny bike. Try to use them a bit beyond their intended power levels (Dreer 880) and it doesn't work.
Run them fairly hard at the lower level and they will almost run forever.
With the occasional rebuild added they will run forever.

Glen
Click to expand...
Quite right, the stock bike is a fine bike and there is nothing (much) wrong with it.

But then again, there are many upgrades that many people enjoy on their bikes.

Your statement that tuning them to race spec will make them last less long, is, of course, correct.

But this thread isn’t about it racing, it’s about upgrades, and there are many upgrades available that can enhance people’s riding pleasure.

I’ve ridden standard Commandos, a single Mikuni Commando and then mine with the JS rods, pistons, cam, etc. To me, a low CR and single Mik defeat the point of having a Commando, but that’s just me, it doesn’t make it ‘wrong’.

That JS kitted motor of mine is a peach, it’s a smoother, much freer revving motor with much more power available. All on a stock crank, cases and box too!

In terms of ‘bang for the buck’ it trumps the full Maney 920 (but not in terms of outright go). So I find it irksome when folks diss such mods in public, especially when they’ve never tried them, especially when they claim to be talking about what works and what doesn’t.

Unto each his own.
 
Why I started this thread on upgrades I am more about a road registration bike and my build motor is mildly done for midrange performance but it has also help with top end performance not as much for racing but for getting up there quicker, these days my high speed running has slowed down but being able to cruise on between 70 and 90 miles for long periods of miles without problems and getting to those speed quicker and to take to the ton and beyond when I feel like it without running out of go juice.
I still run the stock 19th tooth on the GB as with the cam and work it gets up there pretty quick, in my youth I did a lot of burn outs on my Norton, yes young and silly and same after building the Featherbed I soon found out it was a good wheel stander and stood right up and had a great balance without flipping it, but doing all these things in my younger days put a lot of strain and stress on the motor before my rebore my bores were oval shape caused from doing burn outs and doing wheel stands all the time put strain and wore out other things like chains and sprockets as well tyres and eventually stress fractures in my crank case, done a weld repair but eventually was best to replace them all from flogging my motor in youth.
When I matured and stopped doing burn outs and all my silly things and rode the Norton the way I built it, it became a very reliable bike and after that things weren't breaking or wearing out and only replacing minor things from mileage wear and tear on but I also well maintain my Norton which help it to be very reliable and running STP mixed with my oil has helped in my opinion, I still ride my Norton hard but I just don't flogged it like I did in my younger days.
I know how far I can take my revs without over stressing my motor but it get up there pretty quick compared to my old stock motor, it's built to breath and it does it well and sometime I still might pull a good wheelie when the moment is right as it does it so easily, these days I ride smarter without flogging it and the upgrades I have done over the 40+ years has turned my HOTROD Norton into a great road holding motorcycle and a fun bike to ride and play with without spending way too much.
I have never been a rich person and all money spent on my Norton I had to save and do thing one at a time when I had spare cash, I could never throw a big bucket of money into it in one hit but I did it over time and did it while the Norton was still on the road as it was my only transport for most of its life but I did have my new 81 Triumph Thundebird but I had that before marriage and kids, it helped when doing major upgrades on the Norton and some of the times it was pulled down, it was off the road for 3 years while looking for good crank cases as the weld jobs did end up leaking again around the crank seal area which is the finest part of Norton crank cases.
So in 46+ years of ownership my Norton spent about 6 years off the road close to 3 years building it into the Featherbed back in the early 80s and 3 years while chasing up crank cases and the change over so not bad really 40 years of being on the road and 20 + years it was my only transport no matter the weather and was my main going to work bike.
My good Mate Don who got me into Norton's and Featherbed frames way back in 1976 to this day can't believe how good my Norton has been for me and he was the one that said I have a freak Norton, in the late 70s he started to build Tritons and got rid of Norton motors from his builds.
 
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Fast Eddie said:
Quite right, the stock bike is a fine bike and there is nothing (much) wrong with it.

But then again, there are many upgrades that many people enjoy on their bikes.

Your statement that tuning them to race spec will make them last less long, is, of course, correct.

But this thread isn’t about it racing, it’s about upgrades, and there are many upgrades available that can enhance people’s riding pleasure.

I’ve ridden standard Commandos, a single Mikuni Commando and then mine with the JS rods, pistons, cam, etc. To me, a low CR and single Mik defeat the point of having a Commando, but that’s just me, it doesn’t make it ‘wrong’.

That JS kitted motor of mine is a peach, it’s a smoother, much freer revving motor with much more power available. All on a stock crank, cases and box too!

In terms of ‘bang for the buck’ it trumps the full Maney 920 (but not in terms of outright go). So I find it irksome when folks diss such mods in public, especially when they’ve never tried them, especially when they claim to be talking about what works and what doesn’t.

Unto each his own.
Click to expand...
Nigel, we seem to be in violent agreement on my main points at least!

On your 850 engine, it sounds wonderful, but if memory serves it hasn't covered a lot of ground yet?
I recall version 1 had the piston coating problem and was rebuilt, used for awhile then replaced with the 920 Maney?
My 920 is running great, was cheap to build but I'm not ready to declare it a success with just 4,000 miles on so far.
If it makes it to 25,000 miles without trouble then it might be worthy of recommendation.
My main point is for those who are not flush with funds- you do not need to tear your working engine apart to replace the pistons and conrods with lightweight items. The stock items work just fine, that is proven.

When I first posted about purchasing the RGM 920 kit about 10 years ago JS pmed me . He informed that I should throw the RGM 920 stuff away or sell it on and buy his stuff.
I most definitely disagree.

Glen
 
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Yes how much would Jim's stuff cost compared to RGM stuff, I replaced my Amal carbs with a set of Jim's PWKs he was great to deal with and set them up for my motor, the Norton ran great with them but one problem I had was sticking floats, not all the time but enough to give me the sh.ts, Jim was good in helping me to resolve the problem but the last 6 months I had enough and now gone back to my old Amal, I never did have much problems with them, my original Amals wore out within 20k miles and were replaced when building the Featherbed and still no sign of worn slides but had suffered the block pilot jet, I sent Jim a pic on one slide out of the PWK carb showing sign of wear on the chrome slide and still the sticking float on the left carb.
Jim is still trying to get me to do another fix with them but as I told him no I give up trying to solve the problem and have already installed my rebuilt Amals, problem solved, but I can't complain about Jim's help been pretty good and has offered to send a new slide as only one had wear.
He no longer sells them PWKs but he still runs them on his work bike.
 
worntorn said:
Nigel, we seem to be in violent agreement on my main points at least!

On your 850 engine, it sounds wonderful, but if memory serves it hasn't covered a lot of ground yet?
I recall version 1 had the piston coating problem and was rebuilt, used for awhile then replaced with the 920 Maney?
My 920 is running great, was cheap to build but I'm not ready to declare it a success with just 4,000 miles on so far.
If it makes it to 25,000 miles without trouble then it might be worthy of recommendation.
My main point is for those who are not flush with funds- you do not need to tear your working engine apart to replace the pistons and conrods with lightweight items. The stock items work just fine, that is proven.

When I first posted about purchasing the RGM 920 kit about 10 years ago JS pmed me . He informed that I should throw the RGM 920 stuff away or sell it on and buy his stuff.
I most definitely disagree.

Glen
Click to expand...
Yes I had some fancy coating come adrift which was annoying ! So in terms of what works and what doesn’t work, I wouldn’t do that again. Doesn’t really have anything to do with the rest of the upgrades though.

My 850 JS motor served me well for 7 years until I replaced it with the 920 (which also has JS rods and pistons). The 850 is still in great shape though. The 920 is now in its 3rd year (I think) as a road and track day bike, but is being retired from regular track use so will accrue more (and more gentle) miles on the road now.

My 920 JS pistons, even with raised crowns giving 11.1cr, are actually fractionally lighter than stock 750 pistons. In my book, that’s a good thing.
 
Handling and stopping upgrades are the most important ones, and increase both fun and safety beyond power mods on a Commando.

Better brakes - upgraded pads and braided SS lines, 13mm MC. Preferably a better calliper/disc.

Better shocks. Adjustable rebound/compression on them and the forks.

Modern tires.

Brighter lighting, always on.

New isolastic rubbers of correct spec.

These to me are all mandatory improvements that are safety and fun focused.

The rest is all gravy.

My rebuilt motor spins more freeely and revs up more quickly then in its stock form. And it is much smoother along the whole way. There are so many things that go into that that are not stock.

But if you were to rebuild your motor, with the desire to keep it stock spec, I would certainly have a good crank balance done with the new parts. You want to make it as smooth as possible. I am pretty sure that is non-stock.
 
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