Feather-Elastic

Does anyone have measurements to the locations of the Isoelastics on a featherbed frame if one is to attempt the feather-elasic modification?

Before I did a Featherlastic I'd rather use JS Pistons and Rods.

Featherbed frames were designed to have hard mounts, changing anything on a Featgerbed frame is going beyond the whole idea of a good handling frame, I have been running my 850 Comammando engine in my featherbed frame for over 30 years now if you ballance the crank for the Featherbed you won't have any troubles with vibrations, why muck around with a great handling frame as it don't cost that much to ballance a crank.

Ashley

swooshdave said:

Before I did a Featherlastic I'd rather use JS Pistons and Rods.

Click to expand...

I'm with Matt on this here CDubb
You have a very nice 28 lbs Commando frame. No featherbed will be lighter…. unless its chromemoly tubing…even then I still think the Commando frame is lighter. Ludwig vouch for me on this one…. When the commando is set up well with Iso and Swingarm mods and wheel alignment and such. It is a sweet ride. You already invested in the GPM pistons and they are heavier than the fully slotted Hepolite pistons that I told you to turf.
Do the Production road racer theme...you bought most of the parts. Matt…. help this man out will you. He is turning to the dark side...Mods and Rockers and such.... :mrgreen:
By the way…
After a good ride on my 74 interstate today and then dinner, a few glasses of Mendoza Malbec to calm my soul.... I got to look into why the gearbox was not turning from the weekend after we buttoned it up. Your gearbox is fine...One gear was backwards.... We talked about that issue in the Mick Hemmings video remember...
All is now well in Norton Land. It is now ready for the outer cover bits to go together. Bring Gear oil.... EP90 :wink: and beer.
Cheers bud

CNN

According to Les Emery, if a featherbed mounted Commando or Atlas engine is balanced to 84%, which is also Paul Dunstalls number, then it results in a smooth running bike.
He also said that the featherbed machine will never be as smooth as the standard rubber mounted Commando, which seems logical.

Handling is another topic and much of that discussion is subjective, especially for use at road bike speeds.
The look of a Norton twin engine in a featherbed frame is hard to beat though. That is also an individual viewpoint, however it is one that a lot of individuals seem to agree on.

Glen

If the Atlas I rode a few times was an example, I don't think I'd consider anything bigger than the 650SS motor in a Featherbed frame. The story around N-V was that the headlamp bulbs on an Atlas only lasted about 5000 miles and it didn't make a difference whether they were ever switched on. The vibrations used to shake the bulb filament off the posts. Even my 650SS would make your toes and fingers go numb after 100 miles or so.

Frank, I chatted with Les Emery a couple of weeks ago on the subject of Atlas vibration.
He told me that many of the problems with the Atlas arose because of the deadbeat subcontractor machinist hired by Norton to do the crank balancing. Cranks assemblies were sent to him, he drilled some token holes to make it appear that the cranks were carefully balanced.
Les has encountered untouched Atlas bikes with anywhere from a 40% balance factor all the way to 92%. Once they are put right to 84% he claims they are quite smooth.
Makes me wonder if the same person balanced the crank in my 68 650 SS. It is reasonable for vibes, but I would happily take it apart for rebalance if I knew it was needed.

Glen

My 850 motor was balanced at 72% 32 years ago I have clocked up a lot of miles on this featherbed framed 850 well over 120,000 miles and have done a few 600 mile runs straight with just the nomal stops (fuel, food and piss stops) and I always cruse on around the 70-75 MPH highway speed, around town I never go under 40 MPH and is very smooth at that speed, I run a belt drive primary as well, but if I ever need to rebuild this bike again (rebuild 18 months ago) I would think about going the lite pistons and rods from Jim, at the moment I have the orginal rods and 40th oversize Hepolite pistons, but have other work as well to the motor for sweet running.

Ashley

worntorn said:

Frank, I chatted with Les Emery a couple of weeks ago on the subject of Atlas vibration.
He told me that many of the problems with the Atlas arose because of the deadbeat subcontractor machinist hired by Norton to do the crank balancing. Cranks assemblies were sent to him, he drilled some token holes to make it appear that the cranks were carefully balanced.
Les has encountered untouched Atlas bikes with anywhere from a 40% balance factor all the way to 92%. Once they are put right to 84% he claims they are quite smooth.
Makes me wonder if the same person balanced the crank in my 68 650 SS. It is reasonable for vibes, but I would happily take it apart for rebalance if I knew it was needed. Glen

Click to expand...

I had an Atlas and hated the vibration, so I stripped it apart and rebalanced the crankshaft to a factor that Norton recommended. Perhaps it was the high 10:1 pistons, but it still didn’t make much difference. So if anybody out there got an Atlas engine running smoothly, without restoring to using Commando Isoelastics, good luck to them.
In the end I gave up and brought a 500/4,- what a difference :!:

I guess you could say that is what Ashley has, since the Commando motor is essentially the same as the Atlas motor. In the case of Ashley's bike, its the 850 he has bolted up solid in a Featherbed so vibes ought to be even worse than with an Atlas, yet his is smooth.

Glen

frankdamp said:

. The story around N-V was that the headlamp bulbs on an Atlas only lasted about 5000 miles and it didn't make a difference whether they were ever switched on. The vibrations used to shake the bulb filament off the posts. Even my 650SS would make your toes and fingers go numb after 100 miles or so.

Click to expand...

Rubber mounting the headlight is not rocket surgery and it makes the bulb last forever.

I don't know if I have been lucky or if it was the very good work of the old English gentlman that ballanced my crank on my 850 that has made my Featherbed work so well, when I gave him my crank and all the other bits that bolted to the crank and told him what I was doing, he knew all about the ballance factors of Norton cranks so 32 years with this crank I think he was spot on with what he done.

I am building a 61 650 Manxman at the moment, it was set up as a race bike many years ago and had good racing history, the crank has been ballanced, has hi comp pistons (the mortor was build up as a 650SS motor but with more work done on it) the only thing that was missing on the motor was the head, it was stolen from the P/O shed so I don't know what was done to the head, I can't wait to have this bike on the road to see how smooth it will be and how much diffrents it is to my Wideline Featherbed 850, you can read about it in this section New Project Bike, I will be starting the engine rebuild in the next week or so when time allows me.

Ashley

As for the headlight bulb, I am still running the orginal bulb that came with my 850 from the factory in 74, I have owned this bike sense new and convered it to the Wideline featherbed in 1980, but have gone throught a few tail light bulbs over the years, except for now sinse I have put some elec tape around the bulb where the glass and metal of the bulb meets it hasn't blown so far in the 6 month I have done it.

Ashley