Topic: Is my frame bent? Is my method flawed? Lot of pictures!!

[albertaboy]

Then I drew a mega long straight line on the floor and with the set up on the center stand, I carefully aligned the wheels together the best i could. Following the video posted eariler in this thread. I found the measurement almost exact. Off by 1 mm and equal at the front and back of the front tire. Again pictures look off kilter but it measures 5mm on one side and 6 mm on the other.  Pretty close? No?


dont know how this pic got tilted. sorry.


I have measured the swing arm pivot and rear axle from the floor but yet not being able to assure the floor is level, all I'll say at this time, all four points measured equal. Off by 1/16 of an inch. Later today hopefully once company is gone, I'll get back out there.

So far Im feeling good about the string test.

[754]

As you have both wheels on, i suggested the vertical tubes method, it will work regardless of level. But things could still be off side to side. The only way it could probably be bent at that point is, a straight back even pushback of front end, or a twist of the swingarm and neck, which both being equal is unlikely.

 Anyway if you try that and it checks out, it is probably ok.
 Keep in mind they were not dead straight from new, well most were not.

[Aurelia B20]

PS Aurelia - will this approach still work if I don't read French? ;-)

No problem ! 

[Magpie]

I thought I had a bent frame too so I got 2 lengths of angle iron and did this: go to page 8 of this thread and scroll down, of course you need the wheels on the bike. http://forums.sohc4.net/index.php?topic=60120.175
We also used a carpenters laser aimed from the centre point of the rear hoop towards the steering head to see how that looked.
One fellow here made a set of cones that will fit in the top and bottom of the steering head, drilled them so a piece of straight rod would fit tightly through the holes and stick up a fair way above the steering head. He then found the centre of the rear hoop and using magnets and a larger carpenter's square set the square on the hoop so the long leg of the square was pointed up. He then stepped back to see if the rod and the square were in line or if the rod pointed off to either side of the square. It told the tale of one of my frames - dammit. Cliff.

[albertaboy]

As you have both wheels on, i suggested the vertical tubes method, it will work regardless of level. But things could still be off side to side. The only way it could probably be bent at that point is, a straight back even pushback of front end, or a twist of the swingarm and neck, which both being equal is unlikely.

 Anyway if you try that and it checks out, it is probably ok.
 Keep in mind they were not dead straight from new, well most were not.

Frank,
Assume  the bike had a header at some point.  The forks and triple checked out as straight- checked by shop #2. I guess a PO could have replaced the obvious damaged parts.  I still don't see any cracked welds or tube deformity or cracks.

About the swing arm. I've now removed it and only using eyesight, it looks very very slightly twisted.  Can you describe how you would go about checking it? What is an acceptable tolerance?

I'd have to buy some tubes and get a helper as the center stand would interfere with the tubes.  I re-did the string test. I leveled the bike on the center stand, by installing the rear lower engine bolt and then the level across that.  I got the same results as I posted earlier today.  Monday I'll contact shop 1 and see if they cant pull up this bike from their records or tell me exactly their test.

[albertaboy]

You are on the right track .


Just use this modified photo and you can find out what you need to know.

Just make sure the swing arm pivot tube is the same distance from the ground on both sides AND LEVEL. Then if the front forks are level by putting a level on the side of them,  it means the steering head is NOT twisted.

On the rear swing arm if the center of the axles are the same distance from the ground and the bike is level (swing arm pivot tube being level allready) ,it means the swing arm is NOT twisted.


You are done!

Click on this photo for a larger version.

Lucky, This is good. I've come back and re read this and I think I answer my twisted swing arm question in reply 54 above.  Leveled the rear like you said. I found my pivot point was equal but the axle point was off... 1/16 to 1/18 max. Seems small to me but I know better.  754 and Lucky (or anybody) what is an acceptable tolerance?

Cliff. I think I have the material to recreate your test. Another check or two cant hurt.  Want some of my snow??? Please.
You are on the right track .


Just use this modified photo and you can find out what you need to know.

Just make sure the swing arm pivot tube is the same distance from the ground on both sides AND LEVEL. Then if the front forks are level by putting a level on the side of them,  it means the steering head is NOT twisted.

On the rear swing arm if the center of the axles are the same distance from the ground and the bike is level (swing arm pivot tube being level allready) ,it means the swing arm is NOT twisted.


You are done!

Click on this photo for a larger version.

[lucky]

Lucky,

What's the best way to make sure the swing arm pivot tube is level?
I assume you can't just put a level on top of it, or can you?

Thanks,
Chris

Yes... just put a level on top of it and use shims under the center stand until it is level.
Then check that the front forks are perpendicular by putting a level on the side of the fork tubes.

[lucky]

If you are using the measuring from each side of the axel centre to the floor method, you have to make sure the neck is perpendicular to the floor.  I wouldn't use the centre stand

Slight misunderstanding.
I did not mean the axle center to the floor. That will mean nothing.
There is nothing wrong with shimming the center stand to get the swing arm pivot tube LEVEL.

[lucky]

This whole story reminds me that one time I was a welder at an airport and
I was building tubular engine mounts with chromoly tubing for a WWII Widgeon aircraft.

After I finished a pair of the engine mounts this new man in the shop who did not like me.
He had the owners buy a large granite measuring table and some very expensive measuring devices to measure my engine mounts.

I got tired of being micromanaged. I did not mind having my work inspected ,its just that this other employee never quit dogging me.
So one day I took the owner out to  the yard where many other planes were being stored and I showed the owner by measuring with a tape measure that the original engine mounts would all have slightly different measurements.

Then I showed the owners that the Factory shop manual showed that to align the two engines of this WWII airplane that a step ladder ,a piece of string 12 ft. long and some washers were used to align the engines.

I showed the owners we did not need rocket scientists, laser beams or computers for this job. owners started to understand.


But that employee persisted and insisted on a static destruction test.
Otherwise take a finished engine mount (many hours of work) and test it to destruction.

So they set this test up and it was supposed to put a 2G force on the
engine mount. Nothing happened. So they kept going and put 6 G's of force on the engine mount. Still no failure. Then they quit and the next day they re measured the engine mount and found out it was tweaked by 1/4 inch. No fractures no failures.
BTW the $500,000 engine was in the frame.

There is no end to the doubt.

[754]

Level swingarm pivot, install swingarm, install axle(same mark each side)..put level on it..done.

 By tubes i meant flourescents, ,not hard to come by. Or use other known straight items.

 The problem with going on the floor alongside tires, is if anything is swapped, moved a bit, or swingarm is bent sideways, it makes frame appear bent.

[Kickstart]

My only concern with the fluorescent tubes... is how do you know they're straight enough?

I tried to research what the manufacturing tolerances of fluorescent tubes are, but couldn't find any information.

[scottly]

Level swingarm pivot, install swingarm, install axle(same mark each side)..put level on it..done.

The swing arm can, and possibly should be checked for twist, off the bike using a similar method.

[754]

Kickstart that is a good question, if you have two you can self check them, same way as fork tubes.

 Hold together and up to a light, look for airgap between them, if there is none they are straight at that orientation.
 Now turn the top one 90 degrees. Check, repeat a few more times. If it checks out that one is straight.
 Now roll the one below 90 degrees check...repeat a few more times.

 Works the same with forktubes, if there is a bend, there will either be a gap, or it will rock. This will work with assembled forks.

 Next we have different types and qualities of levels, hence I re comend the self check.

 When you are checking a alignment with four foot or longer fluorescent tubes,you can be pretty accurate.
With a bike rolling on two wheels if the lighttubes are parallel, the rest of the alignment is easier.
 The hard part of doing it is holding the tubes and making sure its against the tire properly.

[754]

 Is this making sense to a few of you ? I know most of the guys in my trade would easily understand that.
 But if it is not making any sense, it may be difficult to explain it better, for me.

[albertaboy]

Is this making sense to a few of you ? I know most of the guys in my trade would easily understand that.
 But if it is not making any sense, it may be difficult to explain it better, for me.

I think I'm getting it. Lol. No I've got it. I want to post the end result of my findings, just haven't been able to get back to it.  So I'll take some pic and post them in the next week or so.  I am able to see my frame isnt bent. I'm not sure about the twist (if any) in my swing arm.  Although, I wonder where the 3/4 inch discrepancy went. I'm still working that one through....

[lucky]

LOL lucky... you know there's a text option in your editor, right?   

I do not know what you are trying to say. Also I do not know what the text editor is.
Is it part of this webpage or something on my Mac computer?
I have no idea what you are trying to tell me.
Is it some kind of put down?

[Black 750K8]

LOL lucky... you know there's a text option in your editor, right?   

I do not know what you are trying to say. Also I do not know what the text editor is.
Is it part of this webpage or something on my Mac computer?
I have no idea what you are trying to tell me.
Is it some kind of put down?

Maybe it has something to do with the red marking? I don't know either.

[iron_worker]

I believe he is saying there is some sort of built in functionality to edit pictures right in the forum programming itself. Though you may have just pulled the picture into Paint (or similar) edited and re-posted. He was remarking that you used a "paint brush" tool to make text instead of an actual text editor.

Back to the real topic at hand:

Is it possible that rear wheel/axle was just misaligned (axle adjusters not set equally on each side) when it went in to have the MOT test as you said the bike was assembled/running then. Maybe now that you've put it together again you have now properly aligned the axle.

Would be a simple fix and a pretty silly reason for the whole bike to have been stripped down. lol

Doing some simple geometry in my head ... if the axle is roughly 12" between the swingarm and the bike is roughly 6ft front front axle to rear axle...

3/4" out of alignment at the front of the bike (if the string test was used as shown in the vid) would only require the rear axle to be froward by 1/8" on one side.

Those distances aren't exactly right I'm sure but just showing that a small amount of difference at the back could make a big difference when you're taking the measurement at the front.

IW

[albertaboy]

Would be a simple fix and a pretty silly reason for the whole bike to have been stripped down. lol
IW

You know what's even worse??? Two highly trained and highly experienced techs from two different shops not thinking it might be something simple and wanting to tear the front end apart, charging the customer $125.00 and hour to do so.  Silly, would be allowing them to do so.   Instead, I found a Alberta titled frame, swapped all the parts over and got riding.

[dave500]

did you swap the forks to their correct sides?

[calj737]

Is it possible that rear wheel/axle was just misaligned (axle adjusters not set equally on each side) when it went in to have the MOT test as you said the bike was assembled/running then. Maybe now that you've put it together again you have now properly aligned the axle.

Would be a simple fix and a pretty silly reason for the whole bike to have been stripped down. lol

IW

I didn't have the heart to throw that dart at him, IW, but thank you for breaking the ice!

More times than not, "mechanics" want it to be the most complicated damn thing in the world. These bikes just aren't capable of the "complex" structural/suspension geometry problems. Hell, a tape measure, some string (or flouro tubes) can set most anything up on them.

Alberta - I do think at the end of the day, while you spent some time, you have learned a great deal. I am inclined to believe the rear axle/swing arm over anything else as you've indicated countless times that nothing is visibly damaged. And all your tests have proofed pretty darn near perfect straightness.

Tell you what, for a Non-resident Deer/Elk/Moose tag (whichever) I'll drive up and hold them while you smack them! OR vice-versa....

[albertaboy]

IW- I just got off the phone with shop 1. I spoke to the same tech that checked the bike's alignment back in 2010. He says checking that the rear axle isn't off is the first thing he does. He verified that string from the rear tire is fact the test they do. I asked him what the mis-alignment tolerance was for a pass or fail.  He said there isn't a defined tolerance but it's what he thinks is safe or not as he "signs" his name and license to the certification. He wants to cover is @ss.  Can't blame him still I politely let him know all the BS I've gone through with this so He's willing to take my rolling chassis and check the alignment for me.... NO CHARGE!!.  In the end it all works out- if I build a bike on this frame I'll know it will pass the safety check before hand.

The tech also told me he remember my bike and how he received a phone call from shop 2 . They discussed the potential problem and they both agreed the front end, being steering bearing or bent fork tube or triple was the problem.

Dave500 - lol. Good eye. No! I did my tests with the forks in wrong. I seen your post while speaking to the tech so I was able to talk to him about it.

calj737.  Lol. Ya throw darts. It's all good. I didn't know a thing a back in 2010 and learning was the reason I bought the bike in the first place. Yeah I've learned from this thread. It's all common sence how to check a frame....but common since isn't common.  Back then, I just went with what the two techs were telling me and instead of dumping money into their labor, a good plan B was find the other titled frame.   Hunting licence? nah... just come up and poach.... just kidding.

In case anyone is wondering, I didn't strip the bike solely for the purpose of checking the frame.

[LesterPiglet]

My only concern with the fluorescent tubes... is how do you know they're straight enough?

That's so funny.

[dave500]

i tried the fluro tube method and its #$%* house!

[calj737]

Dave500 - do the tubes energize anti-clockwise as the water does since you're in the southern hem? Just curious...