- Nov 2, 2011
any photos or advice please
Solid mounts are all part of the handling in a Featherbed frame, put rubber mounts and it won't be the same and really the only thing you hear about the Featherlastic builds are from the builders who was selling them, you can get a smooth Commando/Featherbed by balance factor or light weight engine parts but I went with the balance factor of my crank at 72% I built mine in the early 80s and I still ride it today and after 39 years have only lost the top gear box nut and one muffler mount bolt.Featherlastic has been done, but IMO doing so is an exercise in futility.
The beauty of the Featherbed frame lies in its excellent rigidity, despite its light weight. It gains this rigidity by utilizing the engine and gearbox to stabilize the inherent weak points in the frame, those being at the sweeping radii of the twin loops. Putting isoelastics at those points loses that rigidity.
More on this concept is found in Reply #137 ... https://www.accessnorton.com/Norton...-against-all-engineering-princip.17675/page-7
I think the point being made, which I agree with, is that if you want to put a commando engine in a featherbed then do it without isolastics - ie: rigidly mounted as all featherbed twins were.Plenty of Featherbeds around stuffed with Triumph, Vincent, Harley and other motors. Why not a Norton powerplant?
A rigid mounted Commando engine will have the wrong engine balance factor, so, crank will need rebalancing.I think the point being made, which I agree with, is that if you want to put a commando engine in a featherbed then do it without isolastics - ie: rigidly mounted as all featherbed twins were.
Quite right, stock featherbed bikes don’t have too many chain issues.I'll bet some crafty person like the one who built the brown one, figured it out where the chain doesn't upset anything, as it doesn't on all stock featherbed bikes.
I like the way the yam fj12 motor is rubber mounted in the frameQuite right, stock featherbed bikes don’t have too many chain issues.
Then again, the engine is solidly mounted. Mounting the engine on isos and the swing arm to the frame is when the issues arise and the chain gets a really hard time.
Which was all known by Norton of course, hence why they did what they did with the isos.
If they Cudda mounted the swinging arm to the frame, I’m pretty sure they wudda !