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

[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?

[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!

[dave500]

both ways its ac current.

[Kickstart]

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

That's so funny.

Now why did you have to go and say that?

It's a serious question... Based on another post here I was using two 4-foot fluorescent tubes to help align my front forks a few months back.  I found that rotating one of the tubes resulted in a distant change at the ends.  I ended up just trying to average the smallest and larges distances... but that doesn't seem very accurate.

Maybe it's accurate enough, and had I done 754's seal check suggestion below I might have verified their "straightness" and picked a straighter tube before wire-tying them to my front forks.

So I think it's a valid point and worth letting others know that the manufacturing tolerances on fluorescent bulbs may not be accurate enough for them to be used as alignment tools.

[dave500]

why not try and straighten the fluro tube first?

[754]

Kickstart..imean self check the tubes against each other, sorry and Ifixed that.
 
Fourescent tubes, are usualluy quite straight, I smuppose therel is the odd exception..

[albertaboy]

Zombie alert
Just a follow up for those who followed this thread, those who helped out and for those who may come across this one day. 

This frame passed my province's government inspection for safety today. I did nothing to take the 3/4 inch bend or other issue out that professionals told me it had. I made a bike out of it took it to a different shop who preform the exact same inspection as the other two and it's now back on the road. I am just glad I didn't scrap it. 

[lucky]

That has got to be the most measured CB750 frame in the world!

The men that charged you $190 should be fined.
You really have to watch yourself out in the world. There are lots of sharks.
I wonder how he felt when he asked your for $190, and you handed it over to him.
!@#!@$^@%^%$@^%^$#@$hd!!!!!!

[dave500]

just out of interest a mate bought an old 750 twin cam,the steering looked out and crooked so we just loosened the clamps and twisted it straight,he got it registered etc after doing the brakes right over and a few other things,i rode behind him eye balling the front and rear tyre together for quite a while,straight as an arrow I think,have some one trail you and look close on a long straight road with no traffic.

[albertaboy]

Dave500- Just out of curiosity, I'll do that. I'll even let a trusted buddy ride it and I'll follow so I can have a look.  Though, like many forum members here, I've ridden a long time and more than once, have I ridden a bike with tweaked handle bars and once my forks on another bike were turned a small amount in the triple after I low sided avoiding a lady on her cell phone. I can say that you immediately can tell there's something wrong. 

I Know how well this bike handled on my test ride and believing that 3/4 is a massive amount of mis-alignment that I would have picked up on right away... I drew my own conclusions why it failed... Opportunity was knocking.  I took in a 35 yr old bike that looked dirty and rusted but despite all the safety aspects were in working order, these guys decided they couldn't pass it.

I've met a lot of hard working, knowledgeable, and honest bike techs in my day. Just not that day. Regardless, I can close the book on this now.