TW wrecks a perfectly good Commando etc.

lcrken

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I like it, one head steady spindle.
Cost AU$14 for the titanium.
1-15/16 long.
9/16 UNF threads done on the lathe with the power off.

View attachment 80497

How much if you walked into a commercial machine shop with a drawing to make one of.

Now that's my kind of crazy, Les. Back when I was dealing with the head steady on my Restomod MK3, I couldn't resist making up a Ti spring pin to replace that heavy stock item. Must have saved at least a couple of ounces. :rolleyes:

IMG_4231 cropped1200.jpg


Ken
 

Chris

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Makes my cut down studding look bad Les. However on a bright note! On mine no one will see it. Lol
 

Time Warp

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A change of plan, the left side will now have a small wing that bolts to the Isolastic housing side plate to set the Springulator unit vertically.

1a.jpg 1b.jpg
 

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I got to setting up for welding.
What drongo gets (remembers) the small electronic angle /bevel box to check things after making the parts by what looked spring vertical by eye.

I had to laugh, the top plate no matter how I wanted it to be right (or would take close) is miles out and the spring to rearward so would clash with the frame cross tube. :rolleyes: :D Doh.

Take two.... It keeps you honest.
 

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The recessed odd shape plate will weld between two of the new brackets (on the right)
The smaller hole will end up 1/4" so a UNF bolt and nut can be used to avoid any chance of that spring holder rotating.
The lower cup to be welded to the frame cross tube has a machined recess for the spring also and that (recess) can also be used for locating a spacer/pre loader as necessary.

Its rubbish day so lawns and garden come first.
 

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I needed a longer zinc 3/8 UNF bolt so that put another 241 kms on the ATDCT's odometer finding one but it was a sunny day with a breeze.

We can only guess how the top bracket is attached on the JC Commando but will assume it attaches at the lower Isolastic bracket bolt location.
Something like this, with a check at vertical to the lower frame rail the spring will now have around a 4mm + clearance to the frame cross tube which will get the lower cup.
The wings are 4mm (machined from 6mm bar) thick, the spring holder is hopefully not going to bend and contact the engine cases.
I read in another thread the engine is somewhere around 90 lbs but that might not be the weight the spring has to contend with, less perhaps.

plt4.jpg plt5.jpg

Because this is eventually a stock Commando these sort of hidden modifications are about it.
 

cliffa

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Aha, everything becomes clear !!

Looking at the pictures 74ok enhanced it's easier to see Jim's handywork. I hadn't realized before that it's using the lower ISO mounting bolt for the upper support.

 

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I think it said in that original thread JC had no Isolastics in the housing just a spacer tube (iirc) and that panhard bar.
It occurred to me (The bracket is done and will do some final work on it tomorrow) having the Isolastics in place will reduce the needed spring pressure.
Maybe in my case all it will do is maintain things centrally which I need for the head steady but not do anything for vibration.
I think I allowed around 6mm of movement to contact (3mm any direction) spindle to bore in the frame hanger bracket , it might be like a jack hammer if not enough, hopefully the spring will stop that.

hs.jpg
 

cliffa

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I think it said in that original thread JC had no Isolastics in the housing just a spacer tube (iirc) and that panhard bar.
It occurred to me (The bracket is done and will do some final work on it tomorrow) having the Isolastics in place will reduce the needed spring pressure.
Maybe in my case all it will do is maintain things centrally which I need for the head steady but not do anything for vibration.
I think I allowed around 6mm of movement to contact (3mm any direction) spindle to bore in the frame hanger bracket , it might be like a jack hammer if not enough, hopefully the spring will stop that.

View attachment 84040
It would be really interesting to compare with and without ISO's.
 

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Maybe the front Isolastic tube could be mounted in the rotary table chuck and a unknown size and number of holes could be drilled through the outer rubbers.
A bit like sitting on the fence, less rubber more spring.
JC did say it was very smooth.

Maybe there could be another one of these spring units above the cradles Isolastic tube.

My biased belief is the Sunbeam S7 / S7 Deluxe / S8 over the period 1946 to 1956 was the inspiration for the rubber mounted Commando engine but have wondered for the future if some of the Commando's Isolastic parts could be adapted to it.

IMG_3492.JPG IMG_3496.JPG

IMG_3493.JPG IMG_3491.JPG

S7D.jpg
 

cliffa

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I love those Sunbeam S7's, they were so advanced for the time. What a shame they weren't a bigger hit. I believe the early examples engines weren't rubber mounted and shook like billy-o. Are they 360 cranks?

Before Meriden closed they developed sort of Isolastic system for the Bonneville using (I think) Mini Metro engine mounts with the engine just sat on top of them like a car engine would be. It was reputed to be very good but I think they only sold a few before it folded.
 

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Yes a one piece 360 crankshaft with external car like flywheel.
The story I read online was the first model (S7 1946 to 1948) went to the South Africa Police (iirc) and vibrated so badly they were sent back where the rubber mounting was added.
There is a long spring in the top frame tube for the cantilever linked seat which adds some comfort and a little more anti vibration.
Perhaps one problem was they detuned the original versions (cross flow head perhaps) instead of uprating the final drive (and many of the wear failures were oil related) that or the 100 mph of that original version could extinguish your smoking pipe at speed and it was toted as a 'gentleman's tourer.

The 1970's Suzuki 750 two strokes had steel sleeve rubber bushings in the engine case mounting lugs (which can be fit to the 1974 and 1975 Kawasaki 750 two strokes having enough material to do so (unlike the 1972 and 1973 cases) so vibration was not just Brit bikes.

Sunbeam-1953-01.jpg


Stud.JPG
 
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cliffa

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Looks like you have a nice collection !! Are those extended studs?

I've just found a picture of the lower rubber mounts on the T140AV. Apparently Bernard Hooper was also involved. It's pretty simple if you compare it to a Commando.


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Time Warp

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The studs were in a Stewart Engineering spacer kit (which I probably should have made)
It really needs a spacer, more oil (they do not hold much) capacity, a windage tray and crankshaft oil scraper.
 
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