Hotting Up A MkIII

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mikegray660 said:
crap - i'm agreeing with pete ! :lol:

dude you and hobut should have a circle jerk - i can see it now

Hotting Up A MkIII
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From what I've heard about you, why not make that your avatar photo?
 
Buy a hyabusa and stick on Norton decals
Jap riders won't know the difference
 
Jed said:
Buy a hyabusa and stick on Norton decals
Jap riders won't know the difference
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No thanks, I could just see that wheezing thing with Norton stickers on it.
Jap riders might not know the difference, but everyone else would.
When you fire up a Commando, everybody takes notice.
 
phil yates said:
Modern cars? I simply can't tell one from the other. For my part, I have a Belgium built job with turbo 1.9 litre diesel motor and six speed box. Handles like a motorbike and stops on a pin. But apparently was never a good seller for unknown reasons. I believe deemed to be too race car in feel for the average Joe. Everything I pick always seems to be dead opposite to what the masses want. I guess I'm not a mass. :)
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A lot of us like to own "different" vehicles...I have a Z3 that is a hell of a machine and fun to drive. Makes you want to drive it. It calls you to get in and go.

I think your starting to figure out the reliability issue with the hop up. There are many people here who know a lot about this and what will work and still be reliable. There are some that know the in's and outs of pushing the limit too. I've noticed that most of them have been very quiet and are probably just enjoying this thread or thinking you are a little crazy...but then I figured that out a while ago :D

The whole adventure keeps us young. I've always found working on my bikes and making them what I want to be the best therapy in the world. Another common thread between those who post here.

Keep asking the questions and do some searches to find the threads that answer the questions. It's all out there. It might be overwhelming the amount of info and the different approaches...has been that way for me at times, but you'll figure it out and have the bike you want in the end.
 
phil yates said:
All makes a lot of sense den. Neither of us far off the mark (i.e. MkIII in fact) at all. There are a few in here who need least ride a MkIII before treating and speaking of it as a pariah. But some just don't want to know. They are comfortable with their closed minds. I'm not here to teach them how to open their minds. Or why they should bother. There are none so blind as……...
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I just re-read this and thought about what you wrote.

There are multiple camps here. The belief that the MKIII is not a Commando is a mistake. Yes it was detuned...but for more reasons than many think. The crankcase was beefed up...why?

When you consider the impact of the Combat "Fiasco", Norton continued to refine the bike in order to insure reliability. Consider the forces acting on them at the time. Losing market share to the Japanese who's major selling point was reliability. It was an impossible task because there was so much of the design steeped in history and they really only put a few bandaids on things. They were putting out fires burning in every direction.

Is the MKIII any less of a Commando? It depends on your perspective. To some it is a better bike. I am in that camp because I don't mind that it isn't quite as fast. It still sounds like a Commando. It still has the torque. It can still scare the crap out of you. It has some very good improvements too. Adjustable isolastics, an electric starter all be it in need of an upgrade.

To many reviewer's of the day the MKIII was the best British motorcycle ever produced. In retrospect that is probably debatable, but it still is a good bike and should not be cast off by other Commando owners...but then these comments will probably start a feud when all the 73 and 74 owners read it :D
 
dennisgb said:
phil yates said:
All makes a lot of sense den. Neither of us far off the mark (i.e. MkIII in fact) at all. There are a few in here who need least ride a MkIII before treating and speaking of it as a pariah. But some just don't want to know. They are comfortable with their closed minds. I'm not here to teach them how to open their minds. Or why they should bother. There are none so blind as……...
Click to expand...

I just re-read this and thought about what you wrote.

There are multiple camps here. The belief that the MKIII is not a Commando is a mistake. Yes it was detuned...but for more reasons than many think. The crankcase was beefed up...why?

When you consider the impact of the Combat "Fiasco", Norton continued to refine the bike in order to insure reliability. Consider the forces acting on them at the time. Losing market share to the Japanese who's major selling point was reliability. It was an impossible task because there was so much of the design steeped in history and they really only put a few bandaids on things. They were putting out fires burning in every direction.

Is the MKIII any less of a Commando? It depends on your perspective. To some it is a better bike. I am in that camp because I don't mind that it isn't quite as fast. It still sounds like a Commando. It still has the torque. It can still scare the crap out of you. It has some very good improvements too. Adjustable isolastics, an electric starter all be it in need of an upgrade.

To many reviewer's of the day the MKIII was the best British motorcycle ever produced. In retrospect that is probably debatable, but it still is a good bike and should not be cast off by other Commando owners...but then these comments will probably start a feud when all the 73 and 74 owners read :) :) it :D
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It is funny isn't it? If we are not arguing about modern bikes, we are arguing about Commando models. I really don't mind because to me ALL Commandos are great and special. I just feel the MkIII represents refinement of what was probably the very best British bike built in it's time. There were others before it (all Nortons), but late 60's early to mid 70's, just nothing like it. And it is still out there in modernised form as a special machine to own. Having a beefed up bottom end on the MkIII is a good starting point for performance upgrades. If I can get my next one to go similar or a bit faster than a combat, I will be happy with that. I want the five speed box so fitting a 19T sprocket will allow very quick acceleration but low rpm cruising speed. Six speeds would be undesirable for me, I'd be doing a Japo on it and it's not needed. I've had some good info via PM from interested guys too, and I very much appreciate that.

I'm thinking of making a poster up to put in here:
"The Unapproachable Norton MkIII"

What happened to the Commando?
They stopped making them in 1974!
That should keep all interested parties happy. :roll: :roll:
 
Tops Direct .

Probly get a 961 for the money , it comes with a Norton Sticker .

A ounce of handlings worth a pound of horsepower .
 
Matt Spencer said:
Tops Direct .

Probly get a 961 for the money , it comes with a Norton Sticker .

A ounce of handlings worth a pound of horsepower .
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Yes,
Even called a Commando as well. Same deal as a revived (by name only) Triumph.
I am sure they are a lovely machine, but I don't want one at the moment.
I still like the real thing. I am not ready to move on.

Phil
 
. I want the five speed box so fitting a 19T sprocket will allow very quick acceleration but low rpm cruising speed.
phil,fitting a 5 speed box with a 19t gear box sprocket will indeed give rapid acceleration,but where are you going to get the low rpm cruising speed from,what rpm would you consider low and what cruising speed would you expect from that rpm,the fifth speed is not an overdrive,in my 5 speed box fifth is the same ratio as a 4 speed which I believe is 1 to 1,pls correct me if im wrong, chris
 
chris plant said:
. I want the five speed box so fitting a 19T sprocket will allow very quick acceleration but low rpm cruising speed.
phil,fitting a 5 speed box with a 19t gear box sprocket will indeed give rapid acceleration,but where are you going to get the low rpm cruising speed from,what rpm would you consider low and what cruising speed would you expect from that rpm,the fifth speed is not an overdrive,in my 5 speed box fifth is the same ratio as a 4 speed which I believe is 1 to 1,pls correct me if im wrong, chris
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Thanks Chris
I guess that is my question. I didn't know what ratios are available in a five speed configuration. I was wanting a final ratio that would equate to my current 4th with 20T sprocket.
I have fitted a 19T sprocket before and yes acceleration is hot. But 4th too low in this configuration. I would consider a 5 speed box superfluous if 5th can't be taller than current 4th.

But alternatively, I could run the 5 speed with a 20T sprocket which sounds the more obvious as I think of it. Then I'd achieve everything I'm trying to.

Thanks Chris
Phil
 
All the 5-speeds for Commandos that I've seen still have a 1:1 top gear. All they give you is a taller first gear and closer spread between gears, so you don't drop out of the power band when shifting at high rpm. That's mostly useful for racers, but not that big a deal for street riders. Same for the 6-speeds.

Ken
 
lcrken said:
All the 5-speeds for Commandos that I've seen still have a 1:1 top gear. All they give you is a taller first gear and closer spread between gears, so you don't drop out of the power band when shifting at high rpm. That's mostly useful for racers, but not that big a deal for street riders. Same for the 6-speeds.

Ken
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Ken
That will be fine for me. The MkIII can easily handle a taller 1st gear. I presume nothing in the MkIII cross linkage would preclude an extra gear in there?

Phil
 
phil yates said:
lcrken said:
All the 5-speeds for Commandos that I've seen still have a 1:1 top gear. All they give you is a taller first gear and closer spread between gears, so you don't drop out of the power band when shifting at high rpm. That's mostly useful for racers, but not that big a deal for street riders. Same for the 6-speeds.

Ken
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Ken
That will be fine for me. The MkIII can easily handle a taller 1st gear. I presume nothing in the MkIII cross linkage would preclude an extra gear in there?

Phil
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I don't know of any problem with fitting a Quaife 5-speed cluster into a MK3 and keeping the original shift crossover mechanism. I did that with one I had back in the late '70s or early '80s, and don't recall any particular issues. But then, I don't recall a lot of things too well from that long ago. You would have to go with a cluster swap, not one of the complete Quaife gearboxes, if you want to keep the crossover, but you'd have to do that anyway if you wanted to keep the kick-start mechanism. If you choose to use the Quaife cluster that has a first gear with the internal ratchet teeth for the kick starter, I'd suggest buying a spare first gear, as they are prone to break (I broke two of them in my PR). If I were going the Quaife route on a MK3, I'd ditch the kick starter mechanism, use the cluster with solid first gear, and just upgrade the electric starter.

Ken

Ken

Ken

Ken
 
lcrken said:
phil yates said:
lcrken said:
All the 5-speeds for Commandos that I've seen still have a 1:1 top gear. All they give you is a taller first gear and closer spread between gears, so you don't drop out of the power band when shifting at high rpm. That's mostly useful for racers, but not that big a deal for street riders. Same for the 6-speeds.

Ken
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Ken
That will be fine for me. The MkIII can easily handle a taller 1st gear. I presume nothing in the MkIII cross linkage would preclude an extra gear in there?

Phil
Click to expand...

I don't know of any problem with fitting a Quaife 5-speed cluster into a MK3 and keeping the original shift crossover mechanism. I did that with one I had back in the late '70s or early '80s, and don't recall any particular issues. But then, I don't recall a lot of things too well from that long ago. You would have to go with a cluster swap, not one of the complete Quaife gearboxes, if you want to keep the crossover, but you'd have to do that anyway if you wanted to keep the kick-start mechanism. If you choose to use the Quaife cluster that has a first gear with the internal ratchet teeth for the kick starter, I'd suggest buying a spare first gear, as they are prone to break (I broke two of them in my PR). If I were going the Quaife route on a MK3, I'd ditch the kick starter mechanism, use the cluster with solid first gear, and just upgrade the electric starter.

Ken

Ken

Ken

Ken
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Thanks Ken
I am learning more every day. I was well aware of the Quaife but have never used or fitted one, nor sure if it still existed. My electric starter is upgraded but I wouldn't give the kick starter away. I'd take my chances with the weaker first gear. One slightly flat battery and that electric gizmo dies in the bum real fast. It has happened to me twice and on both occasions one swing on the kick starter and she was alive. But please don't tell Pete that.

It interests me that 1st gear was raised but 5th equals 4th. That leaves pretty close ratio's in between. I guess though the quaife was intended for racing. Ideally I'd like 1st the same as currently is with 5th equal to 4th i.e. 1:1. But a slightly taller 1st would not harm initial acceleration much.

Phil
 
MK3 gearbox ratios are 2.56. 1.63, 1.22, 1.

Quaife gearsets had a variety of first gear ratios, from 1.91 to 2.36, and second through fifth were 1.65, 1.35, 1.1, 1. The 2.36 first gear was listed as the "road" gearing, and had kick start feature. I think there was also a 2.23 first gear with the kick start feature, but I'm not positive about that one. Quaife did several variations on it's gearsets that fit the AMC box, and there may be some other ratios that were available. I've just listed the ones I've used.

Ken
 
Ken suggested that a five speed is not needed for a road bike. I would go a step further and say that for a high torque broad powered engine like the 850 Commando, a five speed is a/step backward.
I also ride a modern Triumph Daytona 955i that has 160 BHP and six gears. It does go like a rocket, but to fully use the power available a lot of shifting is needed, even tho the engine makes 75 ft. Lbs torque. Typically at 60 or seventy MPH in sixth, I will sift down two gears to pass quickly, three gears to pass really quickly. All of this shifting gets old in a hurry.
It is nice to get on the Commando or Vincent and just open the throttle in top gear, away you go. At most a single shift down into third is all that might be required to overtake quickly when on a hill. When you do shift down, the bigger drop down of the four speed is generally preferable to finding another gear almost the same as the top (1.1 for fourth in the Quaife)
So it has it's place in racing but I see the five speed for the road as an undesireable for an 850 Commando, unless you are going to rework the motor such that the midrange is gone and it is all top end, like some race motors.
We are heading out on a 2500 mile trip next week. My riding partner has a Quaife in his Vincent, we have a four speed. We always leave him behind on hills, not due to power but due to gearing. He finds the Quaife 3 rd to low for any Mountain grade up to the steepest, which is 8% in North America. So he uses the 4th, only marginally lower than top. This does not give the bike the same pulling power that my stock four speed has in third. In third My bike will run pull strongly from about 60 MPH right up to 100 MPH without over revving. It just works better for the road than does the quaife.

I think you would find the same is true with the Quaife in a/Commando, unless it was an out and out race bike peaky type motor being ridden right in the narrow power band at the top end.

Glen
 
worntorn said:
Ken suggested that a five speed is not needed for a road bike. I would go a step further and say that for a high torque broad powered engine like the 850 Commando, a five speed is a/step backward.
I also ride a modern Triumph Daytona 955i that has 160 BHP and six gears. It does go like a rocket, but to fully use the power available a lot of shifting is needed, even tho the engine makes 75 ft. Lbs torque. Typically at 60 or seventy MPH in sixth, I will sift down two gears to pass quickly, three gears to pass really quickly. All of this shifting gets old in a hurry.
It is nice to get on the Commando or Vincent and just open the throttle in top gear, away you go. At most a single shift down into third is all that might be required to overtake quickly when on a hill. When you do shift down, the bigger drop down of the four speed is generally preferable to finding another gear almost the same as the top (1.1 for fourth in the Quaife)
So it has it's place in racing but I see the five speed for the road as an undesireable for an 850 Commando, unless you are going to rework the motor such that the midrange is gone and it is all top end, like some race motors.
We are heading out on a 2500 mile trip next week. My riding partner has a Quaife in his Vincent, we have a four speed. We always leave him behind on hills, not due to power but due to gearing. He finds the Quaife 3 rd to low for any Mountain grade up to the steepest, which is 8% in North America. So he uses the 4th, only marginally lower than top. This does not give the bike the same pulling power that my stock four speed has in third. In third My bike will run pull strongly from about 60 MPH right up to 100 MPH without over revving. It just works better for the road than does the quaife.

I think you would find the same is true with the Quaife in a/Commando, unless it was an out and out race bike peaky type motor being ridden right in the narrow power band at the top end.

Glen
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I've got a 5 speed Quaife box in my Vincent. And I totally agree with Glen. I am seriously thinking of fitting a 4 speed again.
It seems to me that less gears are generally better for motors with broad power bands, but if a motor has a narrow power band, then of course, more gears, closer together, are required.
With the Commando's wide spread of torque and power, I can't see the benefit myself and agree it would be a backwards step to some as the more frequent gear changes would be unnecessary / tiresome.
 
worntorn said:
Ken suggested that a five speed is not needed for a road bike. I would go a step further and say that for a high torque broad powered engine like the 850 Commando, a five speed is a/step backward.
I also ride a modern Triumph Daytona 955i that has 160 BHP and six gears. It does go like a rocket, but to fully use the power available a lot of shifting is needed, even tho the engine makes 75 ft. Lbs torque. Typically at 60 or seventy MPH in sixth, I will sift down two gears to pass quickly, three gears to pass really quickly. All of this shifting gets old in a hurry.
It is nice to get on the Commando or Vincent and just open the throttle in top gear, away you go. At most a single shift down into third is all that might be required to overtake quickly when on a hill. When you do shift down, the bigger drop down of the four speed is generally preferable to finding another gear almost the same as the top (1.1 for fourth in the Quaife)
So it has it's place in racing but I see the five speed for the road as an undesireable for an 850 Commando, unless you are going to rework the motor such that the midrange is gone and it is all top end, like some race motors.
We are heading out on a 2500 mile trip next week. My riding partner has a Quaife in his Vincent, we have a four speed. We always leave him behind on hills, not due to power but due to gearing. He finds the Quaife 3 rd to low for any Mountain grade up to the steepest, which is 8% in North America. So he uses the 4th, only marginally lower than top. This does not give the bike the same pulling power that my stock four speed has in third. In third My bike will run pull strongly from about 60 MPH right up to 100 MPH without over revving. It just works better for the road than does the quaife.

I think you would find the same is true with the Quaife in a/Commando, unless it was an out and out race bike peaky type motor being ridden right in the narrow power band at the top end.

Glen
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Glen, Is this the bike you mentioned previously that had the unique cam grind in it, and if so how are you liking it?
 
When I was considering getting a Silk 700S in the 70s, I had a long discussion with George Silk. One of the topics was "why only a 4 speed gearbox?" He said that strictly speaking the torque band was so wide and so flat that only a 3 speed gearbox was required for road use, but when racing a 4 speed cluster was needed. The Silk 700S was a 700 cc twin cylinder water cooled two stroke.
So that for road use, given a torque output like the Commando why would you want a 5 speed 'box? Clearly racing is different.
cheers
wakeup
 
Glen, Is this the bike you mentioned previously that had the unique cam grind in it, and if so how are you liking it?[/quote]

No, that bike has not run yet, tho it is getting close. I just came in from the shop, the engine is now in the frame. It is an Egli Vincent of sorts, although quite different with modern wheels and suspension, stainless steel frame. It is about fifty pounds lighter than a conventional Egli.

The bike for the trip is a more or less standard Rapide, actually the 38 th one built after WW2, so very early production. It has the usual upgrades for doing high mileages, approximately Shadow tuned, oil seals on valves, low expansion 8 to one pistons, indicators, x ring chain, fully suspended seat, etc. It almost always gets to run two up plus luggage, 40,000 miles of that in the last ten years. Supposedly it has close to half a million miles on it now. I don't know how many rebuilds have been done.

Eddie, my friend John Mcdougall has found a way to make the standard Vincent gearbox shift quickly like a Norton. He recuts the camplate in exactly the same pattern as a Commando AMC , lo and behold it then shifts exactly like a Commando AMC box! So much for stock Vincent gears being too heavy to shift fast, which is a commonly held belief in the Vincent world.
Sorry for the Vincent sidetrack, but the quaife 5 speed vs 4 speed as seen on the road came to mind and I am pretty sure it would hold true for an 850 Commando.

Glen
 
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