Frame blueprinting

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TomC said:
Hi Stevan Thomas
Do you have an up to date link to your article?
TomC in Ohio
Click to expand...

Hi Tom,
I hope this link works format-wise. If it doesn't, google "world's straightest commando" and it should pop right up. The guy who runs the phantom oiler is the guy I originally got the bike from. He was impressed at how well it tracked when he rode it. Here goes: http://www.vintagenet.us/phantom/wsc.html
This is the original article, I'm working on updating it with some new contacts. Robert Newman is no longer with us. I have a frame out now to a fellow who says he can replicate the main frame work on the front and rear iso holes. I will check them when he's done and see how close they are. As stock, my original frame was out approximately by an eccentric millimeter. There are enough other variables, it's good to start with the foundation of the main frame holes being correct.
Stevan
 
MichaelB said:
I am going to start work on a 73 750 fairly soon.
I have read the 'World's Straightest Commando' numerous times.

The question for me is how far do I want to go and how much do I want to spend?

My question for the forum is, who out there has had some experience with frame blueprinting? Has anyone out there done the full 'Ken Augustine' treatment?
Is there any other info regarding Norton frames?
Click to expand...

I wrote the article and have been riding the bike for years...what would you like to know about the experience?
Stevan Thomas
Former Editor of the Norton Notice, newsletter of the Northern California Norton Owner's Club
California USA
 
Alas Ken says the fellow who invested to have this done lost interest and got tangled up other stuff and never gave it a good shake down. Innate factory error produced all cylinders with a .003 cant that should be routine to check and level off. Some Cdo's seem to come with an upward bow in the spine.

Does anyone know how much the power unit was shifted to the LH for chain clearance I'm told?
 
hobot said:
Alas Ken says the fellow who invested to have this done lost interest and got tangled up other stuff and never gave it a good shake down. Innate factory error produced all cylinders with a .003 cant that should be routine to check and level off. Some Cdo's seem to come with an upward bow in the spine.

Does anyone know how much the power unit was shifted to the LH for chain clearance I'm told?
Click to expand...

Hobot, I'm the guy who invested in it and wrote the article. I definitely gave it a good shaking down and have been riding the bike for years. That bike needs the gearbox shell replaced and will be done soon. I'm also building an Interstate and doing everything in the article to that motorcycle, including a Mk. 3 swing arm and possibly cradle, if the eccentric top gearbox bolt gives enough primary chain/belt adjustment.
Stevan Thomas
Former Editor of the Norton Notice
 
Originally pretty much all old Brit bikes had rear tyres no wider than 3.50", but later on when wider tyres were fitted, it was necessary to move the motor over to allow rear chain to clear wider tyres. Its a good idea for front and rear wheels to line up exactly, so centre of wheel rim needs to be on the centre line of the bike. The proper way to measure offset is from a datum point on the hub (brake drum or disc mounting face in most cases) to the centre of the rim. Measuring to the edge of a rim is not accurate as replacement rims may be slightly different width, or a wider or narrower size might be required.
 
Steve Thomas, glad to meet online such a famous Cdo endeavor investor. I used to think it mattered but now know an indexed Cdo hardly matters at all but ease to assemble and better isolastic non binding isolation. Not much to do with handling or resisting hinged onset in the middle of sweeper's accelerating glee.
iN other words there's not much handling-ride difference if slightly crooked or perfectly straight in an isolastic Commando, thank goodness.

The rear rim/tire center in relation to spinal tube was not answered in the NOC post though educational review on what Norton moved this way and that to compensate for power unit offset to LH. On most the Cdo I've checked the rear tire center is offset to LH ~3/16". The hub centering is set by the axle spacers so only the spoking can be used to try to center rim/tire. Wheel mainly needs to align the chain sprockets first, this should result in it centered in swing arm, but leaves tire center offset to LH 1/4" to 3/8" and undetectable but by eyeball on rear loop/fender or string and straight edge measure. I spoked Ms Peel so rear tire centered to spine but don't give it a second thought but for centering ascetics compromise in factory set ups tire to fender viewing.

In support of my conclusions was finding a bunch of other cycle examples of both tires not in one line or centered to frame yet fly fine. I'm sure there is some threshold it matters but perfect sure don't. On the side of road or in my shed I just center rear tire in swingarm by feeling for similar tire/swing arm gap, then nip up.
 
nortonmargarita said:
MichaelB said:
I am going to start work on a 73 750 fairly soon.
I have read the 'World's Straightest Commando' numerous times.

The question for me is how far do I want to go and how much do I want to spend?

My question for the forum is, who out there has had some experience with frame blueprinting? Has anyone out there done the full 'Ken Augustine' treatment?
Is there any other info regarding Norton frames?
Click to expand...

I wrote the article and have been riding the bike for years...what would you like to know about the experience?
Stevan Thomas
Former Editor of the Norton Notice, newsletter of the Northern California Norton Owner's Club
California USA
Click to expand...

Hi Stevan,

I think we missed each other over the years of active membership in the NCNOC. I joined in 1981 dropped out in '86 and rejoined in '97. Where are you these days. Would love to talk face to face about your frame work.

Regards,

David
former editor Norton Notice, former ride leader, former President, current Vice President Northern California Norton Owners Club
 
Good article, one thing it only touches on though is the cradle, well the cradle and front ISO mount, possibly the motor mount bolt holes as well. Any of these being slightly out could undo all of the rest of the frame fixes instantly.
 
On the factory racers they found the engine mountings would move in the cradle so they had the mounting holes reamed out, they were assembled with close fitting bushes in the engine in place of the the through bolt and top hat washers in the cradle. Same for the gearbox.
 
I looked into this subject for some time and came to these conclusions:
The factory dimensions for the frame are not with 0.1mm as specified.
The left side Iso's wear assymetrically, the rear more so than the front.
The swing arm pivot lateral support is marginal.
The rear hub and dual axle assembly stiffness is marginal.
The front fork damping and resistance to deflection is marginal.
Blueprinting the frame is an admirable objective, but negated by the deformity of the Iso bushes and deflection of the thrust caps. Plus the other shortcomings mentioned need to be overcome to make blueprinting worthwhile.

Given the physical nature of the frame, engine / box mounting plates and Iso's the realistic means to improve handling are:
Stiffening the engine and gearbox thru stud assembly, i.e. ream cases and bushes to eliminate radial play and a 2nd gearbox adjuster (left side).
Restraining the rear of the gearbox plates from both left and right frame tubes to equalise load. (several methods)
Bracing between the rear section of the gearbox plates adjacent to the swing arm pivot.
Centralising and restraining the top head steady. (several methods)
One piece rear wheel hub and axle.
A stiffer section swing arm.
And of course, good quality tyres and rear shocks.

I understand a number of forum members have done some or all of these modifications. Some for racing, some for personal satifaction. It's all down to time and money depending on what you want. For what it is, the Commando frame does the job for me.

Mick
 
I did a lot of modifications to my Commando to improve the handling. Some don't make a lot of sense and some of them are just excessive, but it was a lot of fun at the time. I had just gotten a lathe and nothing was safe. I made my share of titanium salt and pepper shakers too.

there's a cross tube below the headstock. A cross tube at the bend under the trans. A 1"x3" box section between the rear iso's. A gusseted 2" tube runs down from the backbone to the box section that looks like an OIF Triumph or Dunstall's Stovepipe frame. there's a link under the trans. The tube for the swingarm spindle was cut out and one was machined out of 2" bar stock then welded into the cradle. It's got set-bolts threaded in it to clamp the spindle. it's 1/4" thick in the center and over 3/8" thick where the bolts thread in. the iso endcaps are machined out of 1/4" plate that are bigger in diameter and thicker to avoid caving in. The PTFE washers are replaced with Teflon impregnated Delrin. There are Hemmings adjusters on both sides. The mounting bolts for the engine and trans are oversized and the holes were reamed for a hand press fit. the bolts have the right grip length so they don't ride on the threads. there are 5 bushes in the rear iso. there's a DT headstedy. The bike has been checked for straightness on a frame table.

The cross tubes and the OIF big tube to the rear iso's aren't the best way to go about strengthening a frame, but I wanted to keep the aircleaner and oil tank, and I wanted to keep the bike stock looking. The more efficient way would have been X tube sections between the shock towers and the rear iso and the same rising from the rear iso to the gusset above the aircleaner, but they would have gotten in the way of everything. The OIF add-on isn't optimal and the stock frame is kind of wishful, but together they're sufficient.

I can knock my feet off the rearsets in corners and ride all day as fast as I want on straights without having to pay too much attention to what the bike is doing. I like it but I think there are one or two of the mods I made that may have actually helped, the rest are BS. If I could only figure out which ones they are.
 
Re:

norbsa48503 said:
Frank the most common bend is right in the strongest part and is easy to find. Just lay a straight edge on the top of the main tube. If it's humped it's been bumped. If it took a hit that bent the forks you better check it. Don't get me wrong I love the 20 pound advantage on the other bikes and being able to see in the mirrors is good too.
Click to expand...

If they are bent by 1/2 inch [front impact] is it possible to straighten them?
 
Re: Re:

john robert bould said:
If they are bent by 1/2 inch [front impact] is it possible to straighten them?
Click to expand...

"All things are possible"

....but not all are cost effective!
 
I hang on every Norton word from Bob Patton and relieved he admits not knowing what is doing what, though pleased as can be about essentially forgeting about the bike as it just seems to know what to do when ya want it too, ahhh...

Peel only had the front mid down frames crossed by 1/2 tube and same at the rear frame big bend, then the 3 links, Pattons rear, Bryan Tryree's front and my top. I put 4 large doughtnuts in the rear iso and removed about half the thickness of the front doughnuts. Far as I can tell its the best handling bike fielded and I have compared to crash states this blunt statement. So my firm opinion now is the single most 80% supreme primary added feature to solve Norton everything is the rear rod, then the other two helpers.

Trixie has a humped spine and 3/8" bent LH bent under tube from head on deer impact the bent stanschion too painful obvious. But with some head steady shims and fitting of the front iso by grinding to pass fairly easy, she's as good as any factory Commando of which I've ridden enough to have a sense of their scope. Lay stanchions against each other and roll em to see. I've had some straightened to use ok, others not.
 
This kind of belongs in this thread, maybe not quite as good as the PTFE derilin but my bike had ISO teflons made out of this stuff
http://www.garlock.com/ViewProduct?product=178&region=3

After 20k miles it had compressed slightly but it was still well and truly in one piece unlike the original teflon washers, now the beauty of this is that they were free, they were cut from the pieces they throw away when they make flange gaskets
 
hobot said:
Steve Thomas, glad to meet online such a famous Cdo endeavor investor. I used to think it mattered but now know an indexed Cdo hardly matters at all but ease to assemble and better isolastic non binding isolation. Not much to do with handling or resisting hinged onset in the middle of sweeper's accelerating glee.
iN other words there's not much handling-ride difference if slightly crooked or perfectly straight in an isolastic Commando, thank goodness.

The rear rim/tire center in relation to spinal tube was not answered in the NOC post though educational review on what Norton moved this way and that to compensate for power unit offset to LH. On most the Cdo I've checked the rear tire center is offset to LH ~3/16". The hub centering is set by the axle spacers so only the spoking can be used to try to center rim/tire. Wheel mainly needs to align the chain sprockets first, this should result in it centered in swing arm, but leaves tire center offset to LH 1/4" to 3/8" and undetectable but by eyeball on rear loop/fender or string and straight edge measure. I spoked Ms Peel so rear tire centered to spine but don't give it a second thought but for centering ascetics compromise in factory set ups tire to fender viewing.

In support of my conclusions was finding a bunch of other cycle examples of both tires not in one line or centered to frame yet fly fine. I'm sure there is some threshold it matters but perfect sure don't. On the side of road or in my shed I just center rear tire in swingarm by feeling for similar tire/swing arm gap, then nip up.
Click to expand...

Hi Hobot,
Couldn't disagree with you more! To each his own and all I can say is there aren't too many people on Commandos riding faster than me. If you do, I'll happily buy you a pint! I'm doing another frame now and just left Mr. Augustine. Most cradles are awful. Just think what happens if the swing arm pivot isn't dead parallel to the motor mount. I'll take a dead straight frame with the wheels lined up any day of the week.
Stevan
 
illf8ed said:
nortonmargarita said:
MichaelB said:
I am going to start work on a 73 750 fairly soon.
I have read the 'World's Straightest Commando' numerous times.

The question for me is how far do I want to go and how much do I want to spend?

My question for the forum is, who out there has had some experience with frame blueprinting? Has anyone out there done the full 'Ken Augustine' treatment?
Is there any other info regarding Norton frames?
Click to expand...

I wrote the article and have been riding the bike for years...what would you like to know about the experience?
Stevan Thomas
Former Editor of the Norton Notice, newsletter of the Northern California Norton Owner's Club
California USA
Click to expand...

Hi Stevan,

I think we missed each other over the years of active membership in the NCNOC. I joined in 1981 dropped out in '86 and rejoined in '97. Where are you these days. Would love to talk face to face about your frame work.

Regards,

David
former editor Norton Notice, former ride leader, former President, current Vice President Northern California Norton Owners Club
Click to expand...

Hi David,
Sorry for the delay, I don't get on the forums often. email me at nortonmarg at aol dot com. love to chat. I'm in Larkspur, Marin County.
 
Cheesy said:
Good article, one thing it only touches on though is the cradle, well the cradle and front ISO mount, possibly the motor mount bolt holes as well. Any of these being slightly out could undo all of the rest of the frame fixes instantly.
Click to expand...

You're exactly right. It turned out that mine was not only the first one, the cradle was deceptively ok. Most of them are problematic...the holes are too big, the swing arm pivot isn't parallel and square to the iso mount. The amount of distortion in the main frame shouldn't be within spec, yet that's how they built them. Ken was on the verge of making cradles, it makes a HUGE difference if you have an amateur welder getting paid piece work vs. a person who understands how the pieces move around as you put heat on them. Then you add, how worn out is it? I'm hoping my Mk3 cradle isn't too terrible!

I'll be in Ken's shop in the next few days sorting out his current Commando jobs and adding mine to the mix.
Stevan
 
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