Heavy flywheel equals more torque? (2014)

Status
Not open for further replies.
P.S. I've ridden a Guzzi with a seriously lightened flywheel.
The old Tonti twins (850cc) had a heavy flywheel (8 kg ?), and alloy flywheels were available (2.2 kg ??).
While it was fun to ride - it would spin the back wheel as soon as you twisted the twistgrip - it would have been lethal to ride in the wet.
It would also stall at the drop of a hat, and was hard to keep alive between gearchanges even.
Silly idea....
 
Matchless said:
Simon,
When I rebuilt the 750 with the Maney crank I also fitted a RGM close ratio gear set. 1st gear as standard is 2.56:1. The C.R. 1st is 2.3:1.( Both these figures are from memory) This doesn't help matters of the stalling variety, but the lighter crank does require more care with the throttle. You will soon get used to this however. The effect once underway is as I said before, quicker throttle response.
If you are going to use the bike for despatch riding I would put the standard crank back in otherwise use the lighter crank, get it dynamically balanced to standard spec. & use genuine Norton ISO rubbers. Vibes will not be a problem.
Martyn.
Click to expand...

I'm fairly happy to say my London dispatch riding days are long gone - although it wasn't all bad! The Maney modified crank became available when I was making enquiries as to the availability of a low mileage mk3 crank as I was thinking of the cost of another set of cases if the original 150,000 mile crank decided to let go. Having talked myself into needing a replacement crank I bought the low mileage Maney crank (big-end journals are to within 0.0002" ovality and on standard dia. Polished on the inside of the journals as well as on the counter weights and then anodised black - smart!) The crank was balanced for standard Carrillo's - so I bought a pair of Carrillo's. The iso's are in good condition - genuine Norton spares are a bit of a sore point - I was about to assemble the cases on Friday and put in a new PW3 cam when I noticed the thread for the sprocket nut was not fit for purpose. Hopefully get a replacement cam today and on the road for Friday at the latest to travel to Cadwell for track day Saturday - no problem!

Thanks for all the replies.
 
Al-otment said:
Matchless said:
Simon,
When I rebuilt the 750 with the Maney crank I also fitted a RGM close ratio gear set. 1st gear as standard is 2.56:1. The C.R. 1st is 2.3:1.( Both these figures are from memory) This doesn't help matters of the stalling variety, but the lighter crank does require more care with the throttle. You will soon get used to this however. The effect once underway is as I said before, quicker throttle response.
If you are going to use the bike for despatch riding I would put the standard crank back in otherwise use the lighter crank, get it dynamically balanced to standard spec. & use genuine Norton ISO rubbers. Vibes will not be a problem.
Martyn.
Click to expand...

I'm fairly happy to say my London dispatch riding days are long gone - although it wasn't all bad! The Maney modified crank became available when I was making enquiries as to the availability of a low mileage mk3 crank as I was thinking of the cost of another set of cases if the original 150,000 mile crank decided to let go. Having talked myself into needing a replacement crank I bought the low mileage Maney crank (big-end journals are to within 0.0002" ovality and on standard dia. Polished on the inside of the journals as well as on the counter weights and then anodised black - smart!) The crank was balanced for standard Carrillo's - so I bought a pair of Carrillo's. The iso's are in good condition - genuine Norton spares are a bit of a sore point - I was about to assemble the cases on Friday and put in a new PW3 cam when I noticed the thread for the sprocket nut was not fit for purpose. Hopefully get a replacement cam today and on the road for Friday at the latest to travel to Cadwell for track day Saturday - no problem!

Thanks for all the replies.
Click to expand...

Looking forward to the post 'race' de-brief on the crank Simon... And the action photos from Cadwell!! Good luck nailing it all together in time.
 
B+Bogus said:
I have an engine sitting under my bench waiting for the day I can afford a Maney crank - he won't sell just the flywheel any more. If I could get a drawing I'd get some manufactured myself.
Click to expand...

Since that day moves to the right with annual price increases.....

We hear a lot of nervousness regradng 40 year old flywheel....a batch of flywheels might be a good idea, they don't have to be as light as Steve's for most uses. How many 'subscribers' would you need to make a batch worthwhile?
 
Al-otment said:
- genuine Norton spares are a bit of a sore point - I was about to assemble the cases on Friday and put in a new PW3 cam when I noticed the thread for the sprocket nut was not fit for purpose. Hopefully get a replacement cam today and on the road for Friday at the latest to travel to Cadwell for track day Saturday - no problem!

Thanks for all the replies.
Click to expand...

Good luck with that!

The comment about the PW3 is a little worrying as I have a new one waiting installation, it has been checked out and no problem was noticed with the thread, but I shall be spinning a nut on at the weekend!

It is not a 'genuine Norton spare' though it is an aftermarket item, but made by a reputable cam grinder, and supplied through very reputable Norton specialists to a proven design, though you may have noticed comments regarding possible out of spec timing figures. Maybe the apprentice did the last batch?

Let us know how you get on timing up the replacement.
 
SteveA said:
B+Bogus said:
I have an engine sitting under my bench waiting for the day I can afford a Maney crank - he won't sell just the flywheel any more. If I could get a drawing I'd get some manufactured myself.
Click to expand...

Since that day moves to the right with annual price increases.....

We hear a lot of nervousness regradng 40 year old flywheel....a batch of flywheels might be a good idea, they don't have to be as light as Steve's for most uses. How many 'subscribers' would you need to make a batch worthwhile?
Click to expand...

Not many - I need two, 3 more would do it, but I still need a drawing!
A decent sketch of one would do - the critical dimensions are already on the existing flywheel.
 
Andy.
Nice project
water cutter ,C.N.C miller ...get on with it! Lump of EN?..what ever ,cut the disc's ,big surface grinder....C.N.C miller/borer..bobs your unk.

B+Bogus said:
SteveA said:
B+Bogus said:
I have an engine sitting under my bench waiting for the day I can afford a Maney crank - he won't sell just the flywheel any more. If I could get a drawing I'd get some manufactured myself.
Click to expand...

Since that day moves to the right with annual price increases.....

We hear a lot of nervousness regradng 40 year old flywheel....a batch of flywheels might be a good idea, they don't have to be as light as Steve's for most uses. How many 'subscribers' would you need to make a batch worthwhile?
Click to expand...

Not many - I need two, 3 more would do it, but I still need a drawing!
A decent sketch of one would do - the critical dimensions are already on the existing flywheel.
Click to expand...
 
Heavy flywheel equals more torque? (2014)

4.5 lb lighter, 1/2" smaller OD. Two locating dowels not shown. Water jet cutting data file available.
 
Thats Right Steve...water jet! EN52 or what ever flame cut makes the surface rock hard. Water is a bit more expensive..but removes maching issues.


hobot said:
Heavy flywheel equals more torque? (2014)

4.5 lb lighter, 1/2" smaller OD. Two locating dowels not shown. Water jet cutting data file available.
Click to expand...
 
If light cranks are the way to go for racing, why did Nourish make his racing cranks heavier than stock? The Nourish crank seems to be the golden standard in competition cranks.

Glen
 
The only thing i know 100% is a lighter crank is just that...lighter. Duncan changed his steel yolks for alloy to shave off a 1lb or so..after all prepelling a 1lb weight around a track takes energy..so a commando crank weighing 4-5Lb more..i know this is not the reason with cranks...but even so 5LB aint light! Imagin racing with 5Lb straped to the tank..with horse racing thats a win or loose issue. Love someone to work out how much energy is required to drive 5lb from zero-100mph..its not as simple as straight up...ie 1lb 33.000 feet in 1 minute=1hp ..or something like that :oops:
worntorn said:
If light cranks are the way to go for racing, why did Nourish make his racing cranks heavier than stock? The Nourish crank seems to be the golden standard in competition cranks.

Glen
Click to expand...
 
Comoz and Ken Canaga and another one or two in the crank porno thread said they were faster around with heavier cranks and comoz added the heavier flywheel helps resist the piston deflection on bearings so less loads to bow crank at hi rpm. I find if traction loss and throttle control is a hindrance to pilot or cycle handling instead of opportunity to get ahead then best stick with rail road wheel inside. So two famous race builders going opposite ways in crank philosophy. As Peel makes turns feel like a series of short straight sprints I'm going lighter-smaller dragster flywheel path.
 
B+Bogus said:
SteveA said:
B+Bogus said:
I have an engine sitting under my bench waiting for the day I can afford a Maney crank - he won't sell just the flywheel any more. If I could get a drawing I'd get some manufactured myself.
Click to expand...

Since that day moves to the right with annual price increases.....

We hear a lot of nervousness regradng 40 year old flywheel....a batch of flywheels might be a good idea, they don't have to be as light as Steve's for most uses. How many 'subscribers' would you need to make a batch worthwhile?
Click to expand...

Not many - I need two, 3 more would do it, but I still need a drawing!
A decent sketch of one would do - the critical dimensions are already on the existing flywheel.
Click to expand...

I am with you for that party!! may be Steve Hobot could supply his drawing.......?
 
Just look a modern Ducatti.

Those cranks are as light as they can make them with counterweights only and practically no flywheel at all and they are the fastest twins you can buy. And the pistons are light and have short skirts. No offense but its obvious that light cranks are better and so are the shorter lightweight pistons. And if someone is talking about lap times - then back it up with proof. You may find that those who say heavy cranks give faster lap times never won a race.

If you talking about dirt track - thats a different story.
 
worntorn said:
If light cranks are the way to go for racing, why did Nourish make his racing cranks heavier than stock? The Nourish crank seems to be the golden standard in competition cranks.

Glen
Click to expand...

Dave Nourish was very clear on this, his words went something like this:

"a heavy crank increases torque at the rear wheel" (note: he never said it creates torque, just increases what gets to the wheel)

"and give better drive out of corners"...

"There's more corners on a track than straights lad... its torque that wins races"
 
worntorn said:
If light cranks are the way to go for racing, why did Nourish make his racing cranks heavier than stock? The Nourish crank seems to be the golden standard in competition cranks.

Glen
Click to expand...

I suspect it has more to do with how they are made than a deliberate attempt to be heavier, though since it works for some, who declare they are more rideable, you pays your money and makes your choice. The benefit of a billet crank over a 3 piece crank is less flex and less stress on crankcases, and they have been cheaper than Maney 3 piece items. And Nourish offered different crank firing angles, because that is easier to do with a billet item. Maney is 360 or.....360

With a Nourish crank you can set a tighter squish with the right rods, as always it is the sum of the parts, not the individual parts.

Steve likes lightweight, so that is what he makes.....except his crankcases!
 
SteveA said:
worntorn said:
If light cranks are the way to go for racing, why did Nourish make his racing cranks heavier than stock? The Nourish crank seems to be the golden standard in competition cranks.

Glen
Click to expand...

More to do with how they are made than a deliberate attempt to be heavier, but some dclare they are more rideable, the benefit over a 3 piece crank is less flex and less stress on crankcases, and they have been cheaper than Maney 3 piece items.

With a Nourish crank you can set a tighter squish with the right rods, as always it is the sum of the parts, not the individual parts.

Steve likes lightweight, so that is what he makes.....except his crankcases!
Click to expand...

That's not quite so Steve, Nourish did make a lightweight crank in the past, I've no idea how light it was, but relative to his 'standard' crank, it was lighter. However, he stopped offering it. And wouldn't even make it when I asked him (I'm going back to around 1999 I guess) and its when he gave me the 'lesson' about torque and corners instead!
 
I think a modern Duke is not a good comparison, 8 valve desmos with super short stroke and narrow V twin cranks..i have seen a engine in bits ..caulk and cheese against a Norton.

cyclepsycho said:
Just look a modern Ducatti.

Those cranks are as light as they can make them with counterweights only and practically no flywheel at all and they are the fastest twins you can buy. And the pistons are light and have short skirts. No offense but its obvious that light cranks are better and so are the shorter lightweight pistons. And if someone is talking about lap times - then back it up with proof. You may find that those who say heavy cranks give faster lap times never won a race.

If you talking about dirt track - thats a different story.
Click to expand...
 
Fast Eddie said:
SteveA said:
worntorn said:
If light cranks are the way to go for racing, why did Nourish make his racing cranks heavier than stock? The Nourish crank seems to be the golden standard in competition cranks.

Glen
Click to expand...

More to do with how they are made than a deliberate attempt to be heavier, but some dclare they are more rideable, the benefit over a 3 piece crank is less flex and less stress on crankcases, and they have been cheaper than Maney 3 piece items.

With a Nourish crank you can set a tighter squish with the right rods, as always it is the sum of the parts, not the individual parts.

Steve likes lightweight, so that is what he makes.....except his crankcases!
Click to expand...

That's not quite so Steve, Nourish did make a lightweight crank in the past, I've no idea how light it was, but relative to his 'standard' crank, it was lighter. However, he stopped offering it. And wouldn't even make it when I asked him (I'm going back to around 1999 I guess) and its when he gave me the 'lesson' about torque and corners instead!
Click to expand...

I must have edited my post as you were responding ;-)

I suspect under the new ownership if the customer asks for lighter, he will get lighter..... ;-)
 
marinatlas said:
I am with you for that party!! may be Steve Hobot could supply his drawing.......?
Click to expand...

I've already asked ;)
Steve, I'm still waiting... :)
 
Status
Not open for further replies.
Back
Top