commando crankshafts

Madnorton said:

I don't think Andy will be holding his breath on anyone contacting him, there is just not the demand for MK3 cranks or pieces.
Surely it would be cheaper to pick up a basket needing restoration and break it for the spares you need, or search globally for the piece you need.

Click to expand...

Surely cheaper, but hardly a comparable alternative. With a new crankshaft you get ZERO fatigue utilisation and no hidden cracks. I have had enough Norton cranks which had to be discarded after crack testing, usually 2 out of 3 samples tested. A new crankshaft is a very good investment for piece of mind, considering the human hazards of a failed drive side or a flywheel, and of course the financial implications of a wrecked engine and possibly a frame damage. If you loose matching numbers in the process, the loss is even greater.
Each to his own. I would rate value of a new crankshaft far above value of a new cylinder head, but that's me.

- Knut

Madnorton said:

I don't think Andy will be holding his breath on anyone contacting him, there is just not the demand for MK3 cranks or pieces.

Click to expand...

You are wrong on this account. Andy is ready to start making 10 samples for a start, but he needs initial orders.

- Knut

mdt-son said:

Surely cheaper, but hardly a comparable alternative. With a new crankshaft you get ZERO fatigue utilisation and no hidden cracks. I have had enough Norton cranks which had to be discarded after crack testing, usually 2 out of 3 samples tested). A new crankshaft is a very good investment for piece of mind, considering the human hazards of a failed drive side or a flywheel, and of course the financial implications of a wrecked engine and possibly a frame damage). If you loose matching numbers in the process, the loss is even greater.
Each to his own. I would rate value of a new crankshaft far above value of a new cylinder head, but that's me.

- Knut

Click to expand...

I whole heartedly agree!
I’m running two new cranks in my two Nortons (920 and1007).

But we’re in a minority mate. For most folks, the intended use vs risk vs cost just doesn’t work out in favour of the financial outlay.

Most people I see out on old bikes ride like old ladies, & would struggle to break the speed limit, let alone a crank.

Matchless said:

Most people I see out on old bikes ride like old ladies, & would struggle to break the speed limit, let alone a crank.

Click to expand...

With my Mk3 Seeley frame, there is nothing above the motor other than the fuel tank. However if I race, in my mind - I am never going to die. So a broken crank is not a worry. However, I never over-rev the motor. I think it could go to 8000 RPM easily 7000 RPM is my limit.

If you revved a Commando crank to 8000 on a regular basis, it would soon become a fifty piece crank, as indeed would your crankcases.

My 850 motor does all it needs to do without revving above 7000 RPM. I never believed in it, and I still find it difficult to believe it is so good. It is just different, and needs to be used differently. When I discovered the handling thing, it was a game changer. But I needed to be careful about the possibility of anyone changing line in front of me in corners. The speed differential in corners is very high. When I passed the three leaders in my last race, the speed difference was about 30 MPH - they were much faster towards the ends of the straights, but they really needed their horsepower. I was never accustomed to having a lot of torque. A 500cc Manx has a lot of torque, but the 850 Commando engine is brutal. The 1000cc Vincent motor is too heavy, and has the wrong weight distribution for a Featherbed frame.
I would like to race against a bevel Ducati 900.

mdt-son said:

You are wrong on this account. Andy is ready to start making 10 samples for a start, but he needs initial orders.

- Knut

Click to expand...

?

mdt-son said:

You are wrong on this account. Andy is ready to start making 10 samples for a start, but he needs initial orders.

- Knut

Click to expand...

No, not at all, I could push the button on getting MK3 cranks made this morning - the design and development was done as ages ago, but guess what the only one enquiry we have is from yourself. Trust me, there really is not the demand for the MK3 crank or its parts - why do you think Andy is waiting for 10 to contact him with initial orders? because he like us has most probably only been asked by one person. And I suspect he is not going to waste machine time, labour hours and material cost for 9 of the items just to sit on the shelf when more profitable items can be made with the cost not sat on the shelf working against him.

What people have in an old Commando is worth having. Perhaps the old bikes could keep on coming if there was a cult following which involved both sport and touring. There are two ways of looking at things such as the Landsdown cup. Historic racing was supposed to save the old race bikes, but It is probably the only available development class. I usually only ever think in terms of old twin and single cylinder British four-stroke motorcycles. That thinking also involves retros. I also like bevel Ducatis.
I suggest our thinking should shaped but not compartmentalised.
Making parts for motorcycles requires economies of scale.
My road car is a Mazda 6 which has a 6 speed close ratio box, and trick suspension.
My race bike is a Seeley Commando 850 which has a 6 speed close ratio box.
In Australia, they are useless - there is nowhere, they can be used to their full extent, except on a race track.
If I race, I am happier if the other guys are riding bikes which are remotely similar to my own. Race organisers often start rule-making by deciding what they DO NOT want.
I do not think that way. I do not care if all the other guys have superchargers and nitro - if they give me a hard time, it makes me happy.

Royal Enfields have computerised fuel injection - they should do something. And beating a 961 Commando might be fun. I would love to race against one of those. I have never been in a race against a bevel Ducati - If I had the opportunity to do that, I would certainly race again. I think too many guys are afraid of being beaten, so they are beaten before they even start. There are some guys in NSW called Gowandloch Ducati - I could not find a way to get on the start line beside them. They have a beautiful 900 bevel. If I had been prepared to race at Broadford, I could have got out in practice and competed against it. Our system of logbooks has stuffed everything.

I saw this Laverda at Wakefield Park, and it almost broke my heart. If I got on a racetrack and that was there, I would really fire him up. Some people do not know how to have fun.

acotrel said:

I saw this Laverda at Wakefield Park, and it almost broke my heart. If I got on a racetrack and that was there, I would really fire him up. Some people do not know how to have fun.

Click to expand...

Ozlaverda

acotrel said:

Royal Enfields have computerised fuel injection - they should do something. And beating a 961 Commando might be fun. I would love to race against one of those. I have never been in a race against a bevel Ducati - If I had the opportunity to do that, I would certainly race again. I think too many guys are afraid of being beaten, so they are beaten before they even start. There are some guys in NSW called Gowandloch Ducati - I could not find a way to get on the start line beside them. They have a beautiful 900 bevel. If I had been prepared to race at Broadford, I could have got out in practice and competed against it. Our system of logbooks has stuffed everything.

Click to expand...

You don’t need no stinkin’ EFI Al.

Your Seeley would beat a 961 on the track easily.

They’re nice bikes, but they’re not powerful, and they’re heavy. Really no match at all for a decent Seeley Commando.

I do not think of my Seeley 850 as being powerful. What it kept-up with surprised me. But I think it was because I am quicker in corners than many other guys. If I come out of the corners quicker, I can accelerate to a much higher speed on the straight, with not so much power. A bevel Ducati is interesting. It can use the high line in corners and still accelerate hard.
When I had the 500cc Triton, I scared myself. I lowered the gearing and led the field for most of a lap, but got passed by 3 towards the end of a straight. I came into the next corner miles too hot and they were there , and all over the place. With the drum front brake, I had to stand the bike up and spear-off to miss them. I never zot through the middle of a group.
I don't think 1970s 4 cylinder Japanese bikes handle very well, but they are extremely fast in a straight line.

If you watch the video of last year's Barry Sheene Trophy at Goodwood, the Australian rider Josh Brookes rode a 1000cc Vincent through the middle of a group in a corner. That is extremely high risk, even for MotoGP riders. I always take the low line, where most of them cannot go.

This may be a tangent , but at least it is related to Norton Crankshafts.
I am cleaning out an old friend's garage and ended up with 3 crankshafts.

-500 Dominator crankshaft.
-850 crank balanced for solid mounting.
-750 crankshaft.

Is there a market for a 500 crankshaft or is this just a paper weight?

Assuming the 850 crank is a Mark 2, would a stock 850 flywheel bring the assembly back to stock balance factor? i

Similar question, would a stock 750 flywheel bring the assembly back to stock balance factor?

Or, would I be better off rebalancing the whole assembly to stock 750 or 850?

As is, the 850 crank is not useful to me.

Matchless said:

If you revved a Commando crank to 8000 on a regular basis, it would soon become a fifty piece crank, as indeed would your crankcases.

Click to expand...

Stephen Hill said:

This may be a tangent , but at least it is related to Norton Crankshafts.
I am cleaning out an old friend's garage and ended up with 3 crankshafts.

-500 Dominator crankshaft.
-850 crank balanced for solid mounting.
-750 crankshaft.

Is there a market for a 500 crankshaft or is this just a paper weight?

Assuming the 850 crank is a Mark 2, would a stock 850 flywheel bring the assembly back to stock balance factor? i

Similar question, would a stock 750 flywheel bring the assembly back to stock balance factor?

Or, would I be better off rebalancing the whole assembly to stock 750 or 850?

As is, the 850 crank is not useful to me.

Click to expand...

You might need to do a bit more investigation before you decide the 850 crank is of no use to you.

Do you know the actual factor used and weight of pistons and rods etc?

What pistons and rods do you propose to use? Rerun the calculation and see what factor you might then have.

What is it about a higher factor balanced crank in a rubber mounting that you think will cause you a problem?

I know what happens with a stock Commando balance factor in a rigid mount and would not do it, but the other way around is likely to be less of a problem.

If you want to mess with it anyway, consider a TGA/Molnar flywheel in place of a 50 year old standard one. It will be less likely to grenade.

Thanks SteveA. The only info have on the 850 crank is the owner's notes, so no idea what rods or pistons he used to balance it. It was used or intended for a Rickman race bike he had. I assumed that the balance for "solid mounting" in his words would would not work well in a stock iso suspension Norton. Perhaps incorrectly.

The only applications I am considering is in a stock bike ridden sanely, so don't see the need for a Molner flywheel.

Why would a crank with a high balance factor be a problem in a frame with isolastics ? All it would do, would be to shake the motor at low revs. I would never try to rev a motor, with a low BF crank. Most Commandos probably get revved to at least 5000 RPM. I think the high BF crank would run smooth at 4000 RPM. I know that my bike rocks backwards and forwards when it idles. But otherwise, I do not notice the high factor at low revs. I suggest that in an isolastic frame, the high BF crank might spin up easier.