Featherlastic commando

I have been looking at the featherlastic commando that bob cox built.....OMG !! What a nice machine !
Any one on our forum have knowledge,opinions ( that's dangerous) or interesting tales of these really cool
"Hybrids" whose building them....what's the approximate cost for one of these machines ?

My 2c here. When I was first looking at making a Norton racer I looked at the Featherlastic idea. Tempting? Yes.
But.

Why?

After thinking and experiencing, I feel (ymmv) that if you want isolastics, well go the standard Commando route, and if you want a better handling, lighter and more stable bike at high speed, just fit a tilted Commando engine in a Featherbed. That is what I did.

It does not vibrate that much even at very high speed on circuits ( about 130Mph @ 7500rpm on the Dijon straight a few months ago) and on the road it is a pure delight providing you follow a few simple rules.

- balance factor the engine for rigid mount, ie higher ratio than on a Commando frame

- be extra careful in balancing your carbs, this tremendously affects vibrations or lack thereof

- use good (I mean good!) shock absorbers and preferably slighly longer than stock featherbed items. Stock is 300mm, I have installed 330mm units and the difference in handling is absolutely remarkable. My bike has 18" alloy Akront front and back and Commando forks. The shock absorbers I am using are French made Fournales, oleopneumatic design, fantastic quality and...about 1kg (2,2 lbs) each!

- use thin tyres: front 90/90/18 and back 110/80/18

The bike in that configuration is a pure joy to ride, both on the road and on the track. Of course my relatively hot 850 engine is part of the pleasure. (PW3 cams, lightened Crank, flowed head with lightened rockers, Dunstall exhausts, Pazon ignition etc.)

Well I have not built one, but I've been through the thought process a few times, and always end up agreeing with Jagbruno.

I even thought about an ISO Seeley chassis at one time.

But each time I think about an ISO framed Commando, I end up reverting to the fact that the ARE ISO framed ! And the stock Commando frame (minus ISOs and asocited cradle etc) is very light too.

By the time you've added ISOs and associated cradles etc to a Featherbed or Seeley, it ain't gonna be light anymore, and you've added rubber into the handling equation, which can't exactly improve it over stock!

So, I always end up thinking either solidly mount the motor in a Featherbed / Seeley or stick to the standard Commando frame.

Thinking about these things is good. Its a lot cheaper than actually doing it !!

Fast Eddie wrote:
"But each time I think about an ISO framed Commando, I end up reverting to the fact that the ARE ISO framed ! And the stock Commando frame (minus ISOs and asocited cradle etc) is very light too.

By the time you've added ISOs and associated cradles etc to a Featherbed or Seeley, it ain't gonna be light anymore, and you've added rubber into the handling equation, which can't exactly improve it over stock!

So, I always end up thinking either solidly mount the motor in a Featherbed / Seeley or stick to the standard Commando frame.
"

Agree! Moreover, the Featherbed frame REQUIRES a solid mounted engine for proper rigidity - the engine/gearbox/side plates are part of the frame equation. There was a thread recently in the Cdo Forum where the Featherbed frame was disparaged as being too "springy". Well yes, it would be springy IF the engine/GB were to be ISO disconnected from the frame, but it is incredibly rigid when the engine/GB is mounted as designed.

Then, there is the problem of the rear chain getting stretched if the engine is allowed to move due to vibration, but the swingarm is rigidly mounted to the frame.

It has been done, so I hear and read, but I have not heard of anyone being competitive with an ISO-FB. If anyone has, I would like to hear of it.

Slick

Having Islastics on a Featherbed frame will just up set the whole part of how a Featherbed frame works, ridgid motor in the frame is part of the overall of the Featherbed frame, when I first seen the Islastic Featherbed many years ago and the cost to get one built, I throught it was just another gimmic to get money for something thats not needed, I built my hot 850 Featherbed over 35 years now with the crank balanced at the right balance factor, hot cam worked head etc etc, if done right the motor and frame will be smooth as a baby's bum, I have never had any problems with vibrations at all, no worst than a Commando in 35 years of riding it hard, I have only lost one muffler bolt and the top nut on the gearbox (forgot to tighten it up) so not bad for 35 years of riding it, I still have all the orginal motor mount bolts that I used when building it.
I have never ridden a Islastic Featherbed frame but you don't hear to much about them these days, mine was built with a Wideline frame, I run Commando frontend (with Lansdown interals) and rear Koni shocks, 19" Akront rims, once you ride a well set up Featherbed/Command combination you will be hooked forever as I am and my 850 Featherbed was my everyday ride for 35 years but now I share my riding time with the Featherbed and my 2 year old Triumph Thruxton so now the Featherbed is semi retired just like me, but I still love taking it out.
I am in the proccess in building a hot 650 Manxman Slimline Featherbed caferacer so I am very hooked on Featherbed frames and how well the handle.
To the poeple who say the Featherbed/Commando's vibrate to much are usualy the ones that have never rode a well set up Featherbed/Commando but are quick to knock them, only the poelpe who have built them really know and mine will cruise all day sitting on 70 to 90 mph without any problems at all except for the coppers (bloody fun police)

Ashley

I'm in the process of building a special at the moment - slightly tweaked Combat engine in a slimline featherbed frame.

I went through the loop of considering ISOs for the sheer engineering fun of it, but rigidity was my main concern, so went up the rigid mounting route in the end.

I have gone for a manx front end with Lansdowne internals and external springs.
Öhlins on the back with modified shim stacks and springs.

gtiller said:

I'm in the process of building a special at the moment - slightly tweaked Combat engine in a slimline featherbed frame.

I went through the loop of considering ISOs for the sheer engineering fun of it, but rigidity was my main concern, so went up the rigid mounting route in the end.

I have gone for a manx front end with Lansdowne internals and external springs.
Öhlins on the back with modified shim stacks and springs.

Click to expand...

Sounds nice. Any pics of the work in progress for us to enjoy??

I don't want to hijack Zefer's thread, so i'll post more piccies on a new thread once I get going on the final assembly.

I just have a collection of parts at the moment after several dry fits.


Finished building the engine at the weekend though!!!

gtiller said:

I don't want to hijack Zefer's thread, so i'll post more piccies on a new thread once I get going on the final assembly.

I just have a collection of parts at the moment after several dry fits.


Finished building the engine at the weekend though!!!

Click to expand...

Gotta love those Maney barrels... maybe on my next rebuild...!

Fast Eddie said:

gtiller said:

I'm in the process of building a special at the moment - slightly tweaked Combat engine in a slimline featherbed frame.

I went through the loop of considering ISOs for the sheer engineering fun of it, but rigidity was my main concern, so went up the rigid mounting route in the end.

I have gone for a manx front end with Lansdowne internals and external springs.
Öhlins on the back with modified shim stacks and springs.

Click to expand...

Sounds nice. Any pics of the work in progress for us to enjoy??

Click to expand...

If intrested I have all the pics from my last rebuild of my Commando/Featherbed that I did just over 5 years ago, if enough intrests I will put them up on new thread, pics include engine rebuild to mounting into the frame to how I mounted the oil tank to final pics to the first fire up.

Ashley

Please hijack my thread I'm drooling with anticipation of seeing and hearing about it,I'm not sold on a ISO/ featherbed just interested
Zefer

There is an online guide to building these.

http://www.ntnoa.org/bobcox.htm

And more
http://www.featherlastic.com/

I always thought it sounded like a solution looking for a problem,
but I haven't ridden or even seen one....

Rohan said:

There is an online guide to building these.

http://www.ntnoa.org/bobcox.htm

And more
http://www.featherlastic.com/

I always thought it sounded like a solution looking for a problem,
but I haven't ridden or even seen one....

Click to expand...

I remember reading them many years ago, but you don't hear much about them these days, how many were built, or feed back from owners that have been riding them for a few years, I would love to take one for a ride to compare with a hard mounted motor that has been balanced for the Featherbed and how well would the Featherbed frame handle with the motor moving on rubber mounts and the poeple who made them are always going to say they handle great, but remember they are building them to make money, they do look good and the poeple that have brought them ride them everyday or would they push them to their limits or just let them sit in the shed to drowl over them and only ride them once or twice a year.

Ashley

Jagbruno wrote:

"use good (I mean good!) shock absorbers and preferably slighly longer than stock featherbed items. Stock is 300mm, I have installed 330mm units and the difference in handling is absolutely remarkable. My bike has 18" alloy Akront front and back and Commando forks. The shock absorbers I am using are French made Fournales, oleopneumatic design, fantastic quality and...about 1kg (2,2 lbs) each!

- use thin tyres: front 90/90/18 and back 110/80/18 "

Very similar set up to my racing Dommie. I used USA Works performance shocks with springs matched to bike and rider weight, but the rest, shock length , wheels, tyre size are all the same. Handles extremely well. Tried a larger front tyre and it stopped going around corners . i.e. it was so stable in a straight line you needed to climb off the bike to get it to turn.

But to go back to the original thread subject. You run a risk of the frame cracking upgrading to Commando engines. I have seen several upgraded featherbed machines with fast motors, modern tyres and fast riders and they all cracked the frame. (Including my 500) Usually around the swing arm mounting area and cross tubes.

Take a look at the history of the New York Norton original race bike. Kenny Cumming's web site. Look at the postings on his original bike back around 2007 2008.

http://nycnorton.com/racer-2007/

You might need to consider a new frame from Andover Norton or getting one made with heavier grade tubing. If this is just for a street bike you might be OK.

Here is my Norton racer just after engine rebuilt, last year. Slimline featherbed, box swingarm, Pazon ignition, PW3 camshaft, Black Diamond valves with special springs, polished alloy conrods, lightened rockers, seriously modded lightened crankshaft, Dunstall exhaust, etc...a LOT of fun to ride:



And this is the bike almost as it is now, after 4000miles with its full Dunstall fairing:



Since that picture was taken, I have upgraded the front bakes by installing Madass' master cylinder with an original AP Racing calliper, 330mm Fournales oleopnumatic shocks and smaller tyres as stated in my description a bit higher in the thread. The sweet spot on highways is 80-90Mph, you feel the bike could do that all day and the next. From that speed, thanks to the PW3 cam and flowed head, it will accelerate to 120+Mph in a few seconds.
Yes, I LOVE THIS BIKE. (Understatement).

So what is the deal with "balancing" the engine to be "correct with the featherbed frame....Who are you guys using to do this type of balancing / Are there fabricated engine and gear box mounting plates available like the various triton engine/frame combo's....there are some vendors offering these mounting plates for the tritons....anything available for a marriage for a commando/featherbed combo ? Obviously I am looking to do a custom hybrid...ive posted about tritons,and now the featherlastic perked my interest,but the solid mounted commando engine in the featherbed frame sounds like the real deal...any info or photos....a build thread...anything to educate myself....would be appreciated.

Norvil sell engine plates for Commano into featherbed, slimline or wideline, £146 a set...

Fast Eddie said:

Norvil sell engine plates for Commano into featherbed, slimline or wideline, £146 a set...

Click to expand...

Standard Dominator or Atlas engine plates can be used for Commando engines as well.

Jagbruno said:

Fast Eddie said:

Norvil sell engine plates for Commano into featherbed, slimline or wideline, £146 a set...

Click to expand...

Standard Dominator or Atlas engine plates can be used for Commando engines as well.

Click to expand...

They would only be OK if you wanted to mount the engine vertical though wouldn't they? If you want to keep the 'Commmando angle' you need something none standard...

When I put my 850 motor in the Featherbed frame I sat it where it needed to be and the right angle then made templates for the front and rear engine mounts then went to work (worked at a tec college for 31 years and was a T/A to a fitter and tuner) in the welding shop they had a profile oxy cutter with a laser all I had to do is copy the templates with a drawing in black indian ink so the laser could follow the patten and cut the engine mounts out of 5mm plate steel, remember this was in 1980 so no plasma cutters them days, to this day I am still using those engine plates, once the motor was bolted all up I made the top head stay, make sure it is strongly made.

I made a set of engine mounts out of alloy a few years ago out of 6mm, but found they vibrated more and the weight savings wasn't much and ened up going back to the 5mm steel plates.

When I need to do major work on the motor all I have to do is unbolt the engine mounts at the frame (5 bolts on the bottom mounts, 3 bolts top mount and the 3 allen head bolts on the head) and lift my whole motor, gearbox and primary out in one go all up less than 20 minutes work.

When converting a Commando mortor to a Featherbed frame the crank needs to be ballance , mine was done at 72% (I think stock Commando motors are at 56%) and it works great for my bike and is a cheaper way than going down the Carllo rods and lighter pistons and all the other goodied you can spend your money on these days, so far after 35 years of riding my Feathedbed and hot 850 combo I have never had any problems with things falling off or any cracks in the frame, nothing at all and I ride this bike very hard, not as hard as in my younger days but still hard, its a great bike to ride and the friends who do get to ride it don't want to give it back to me.

Ashley