Now going custom with alloy bodywork!!

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bwolfie said:
Wow, I am going to move the swingarm to a new thread by itself. That should explode this forum. :twisted:

Seriously, I know it might not work, but it's worth a shot. I don't have any fancy CAD software, well that's not true I have it, I just don't know how to use it.

I'll do some real world testing of it when I get it installed. I'm not planning any trips to Bonneville.

I can always throw the steel one back on, or build version 2.0.

I did copy the latest and best version, so that should be worth something.

We'll see.
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The main thing is you have perspective and you know what you are doing and know what you are getting into.

As for Bonneville, probably the least problematic for a swingarm with little history.

When doing my first AHRMA road racer build based on a sleeved down Mk5 I was at a friends machine shop heating the swingarm in order to get flats for the tire clearnce. I don't recall the exact jigging but after heat the swingarm spindle end was securely fastened to the table of a bridgeport vertical mill. Heat was applied judiciously and a large bar was used to bend the swing warms back to parallel; used a dial indicator across the axle to confirm parallel with swing arm spindle.

The point is that it is amazing to see the cold flexure with moderate force. If you have the ways and means it might be enlightening to do the same with your alloy swing arm and your steel one and compare. Pick a measuring datum for the dial indicator, a fixed weight and fixed leaver arm. On a tangent but along the same lines, if someone has a press (with gauge) and a dial indicator and a few vee blocks it would be interesting to measure load versus deflection on the Norton crankshaft; but that should be on a separate thread.
 
Dances with Shrapnel said:
The main thing is you have perspective and you know what you are doing and know what you are getting into.

As for Bonneville, probably the least problematic for a swingarm with little history.

When doing my first AHRMA road racer build based on a sleeved down Mk5 I was at a friends machine shop heating the swingarm in order to get flats for the tire clearnce. I don't recall the exact jigging but after heat the swingarm spindle end was securely fastened to the table of a bridgeport vertical mill. Heat was applied judiciously and a large bar was used to bend the swing warms back to parallel; used a dial indicator across the axle to confirm parallel with swing arm spindle.

The point is that it is amazing to see the cold flexure with moderate force. If you have the ways and means it might be enlightening to do the same with your alloy swing arm and your steel one and compare. Pick a measuring datum for the dial indicator, a fixed weight and fixed leaver arm. On a tangent but along the same lines, if someone has a press (with gauge) and a dial indicator and a few vee blocks it would be interesting to measure load versus deflection on the Norton crankshaft; but that should be on a separate thread.
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I bet the FEA numbers will be in the ballpark.

If you put a picture of anything on the forum you're inviting comment. The stock swing arm will bend in a good cross breeze, copying it in aluminum will just exacerbate that tendency.

*And a note for some of you, notice that the above constructive criticism was accomplished without attacking the person.
 
"And a note for some of you, notice that the above constructive criticism was accomplished without attacking the person"

one of the reasons I have blocked 2 members of this forum

go for it Wolfie..
 
madass140 said:
"And a note for some of you, notice that the above constructive criticism was accomplished without attacking the person"

one of the reasons I have blocked 2 members of this forum

go for it Wolfie..
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Hey! Am I one of the members you blocked? Wait a minute, if I am you won't see this, but if I am not blocked you will see it but because of it's triviality you may not answer. Jesus, I'm trippin out. I'll edit this tomorrow if I remember.
 
Hey! Am I one of the members you blocked? Wait a minute, if I am you won't see this, but if I am not blocked you will see it but because of it's triviality you may not answer. Jesus, I'm trippin out. I'll edit this tomorrow if I remember.

No you are safe,
 
I just hope you have friend record you going on it when its together - it may eclipse Hobots special slow speed asphalt ballet that we all enjoyed :mrgreen: :shock:
 
Question
If the standard swing arm flex's, as some say...and thats mayby why the wheel spindle snaps..would i be right in thinking a "weaker" alloy swing arm will increase that "spindle snapping" :?: Just a thought over breakfast!

Would i allso be correct in thinking:
As the bike is leaned from side to side the force acting upon the swing arm "move's" side to side, in effect causing a flex..and mayby Hobits carpark antics caused a rapide fail of his spindle by causing this flexing?
Basicly the lean angle "off sets the vertical load" pushing the swing arm from side to side, the greater the lean the greater the force?
 
If the swingarm flexes that much wouldnt a tube steel brace tig welded on be a fix. I am asking because I have never seen one on a Norton allthough it was a popular route in the day on Z1s and Kz 1000s back in the day
 
Yes that is exactly what I mean. It worked wonders if you had the frame braced to take it and done right it looked very trick.
I have toyed with the idea off and on for years. Hmmm may have to give this a go !
 
If the standard swing arm flex's, as some say...and thats mayby why the wheel spindle snaps..would i be right in thinking a "weaker" alloy swing arm will increase that "spindle snapping" :?: Just a thought over breakfast!
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Three things I think gang up on dumb axles, one they are dumb with joining them w/o over lap but right on last stress riser thread cut, the cush drive paddles in soft minumal sized rubber allow the drum/hub junction to bind load right into the last thread cut right there and then the axle deflection d/t factory swing arms doing opposite torsion directions that also focusing loads right into you know what.

Trixie popped as I tried to hi side her off side of rear patch and would of too but for the snap that took up my wind up and unstable to steer as a low tire suddenly.

Peel has boxed Al swing arm and will be further backed up by swash pads on back of Z plates. Al don't bend so much as fatigue cracks. Make a fancy clever brace which will just add to the double taking appreciation and well lust.
 
The swingarm should be designed to take the worst destructive forces that could typically happen to it. I think that has to be when you hit such a deep straight drop off pot hole that when the wheel hits the exit side edge the shocks compress to the bottoming out point and the top of the wheel hits the fender. This situation at speed while leaned in a corner would be the worst stress you could encounter. Any other leaning actions over fairly flat pavement should be a non issue. On a Commando these forces are not confined to the shock pivots and swingarm bushes, the entire isolastic suspended assembly absorbs the shock through the isolastics to a degree as well. Because of the isolastics the Commando swingarm should require less strength then say an Atlas or other ridged mount bike.
 
Started going back together. Still need to figure out belt loosness before drilling top gearbox mount hole. Going MK3 style on this one. Also decided to use my acewell on it. More weight saved plus it is packed with features.

Now going custom with alloy bodywork!!

Now going custom with alloy bodywork!!
 
bwolfie said:
Started going back together. Still need to figure out belt loosness before drilling top gearbox mount hole. Going MK3 style on this one. Also decided to use my acewell on it. More weight saved plus it is packed with features.
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Holmeslice of NYCNorton.com did this with his Seeley Norton and has done a lot of research on belts. Suggest you give him a call before you use the center punch and start drilling.

One thing to keep in mind that these belt systems tighten upwhen things get hot. I am reasonably sure it is due to the spread between the centers increasing due to the hotter aluminum. With alloy engine/trans plates this may be even greater than one with a steel cradle. I have had good performance with a cold 40mm belt tension such that you could easily twist it 90 degrees with two fingers. When hot it would be just snug. Your results may vary.
 
90 degrees is what I have researched, plus I have the belt drive instructions. I have come to the conclusion as loose as possible without jumping teeth when starting.
 
2+ on cold slack about 90' twist and double checked with dragster bike builder with more belts and pulley's than a 4 bladed lawn mower. Another way to tell is you should be able to work belt on and off w/o releasing fixed tension.

I've clipped pot holes like that but didn't twist up swing arm enough to pop lower shock mount out like it did getting edged off path into Graveled drain ditch and had to get bezerk on throttle flat tracker sideways before it hooked to toss bike back to grade before smacking what was ahead in the ditch. A wheelie on soft aired tire can also tweak the long arms on axle.
 
bwolfie said:
90 degrees is what I have researched, plus I have the belt drive instructions. I have come to the conclusion as loose as possible without jumping teeth when starting.
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Still may want to chat with the Holmeslice for his experience, trial and tribulations. While I was breaking drive belts on my ultra short stroke on a very regular basis, he was sorting through the different belts offered. You will probably be fine with the belt you have but the findings are that not all belts are equal in a big way.

As for a Mk3 style, I would go with adjusters. Difficulty to nail the belt centers right on the nuts. I always thought a small pair of light weight eccentrics would be the cats pajamas; something similar to the Rickman chain adjusters.
 
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