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

[albertaboy]

Background
Bought a 1975 CB 750K in the fall of 2010 that came from British Columbia. It was a complete bike I planned to rebuild and cafe. I had taken it on a 20 min road test before laying out the cash. I had to get an "out of province" inspection which is an extensive road worthiness inspection here. I don't disagree with this law.
Certified Motorcycle Inspection facility #1
- Claimed they did a alignment test and found the bike out by 3/4 of an inch. I had never heard of such a thing but that's just me.  They couldn't say where or how exactly. Didn't put it on their lazer as the string test, they explained, is the first initial test and they don't go further unless the customer want to pay higher fees. It failed the inspection which cost me $190.00.  I wanted a second opinion as they estimated 8 hours and more at shop rates to find and fix it.
The alignment test method was never identified, I didn't think to question they're technique.
 
Certified Motorcycle inspection facility #2 (owner is known as the local CB750 expert I found out)
- This guy and his tech, that I described the above to, rolled on the floor laughing. Said " There's no way the bike can be out 3/4 of an inch".  They couldn't understand why facility 1 didnt put it on the lazer "Cause it only takes 5 minutes".  After a two week wait for them to get around to my bike, they came back and agreed the bike was out 3/4 of an inch. Also told me they didn't know where. Said they wanted to take my front end apart, again at hours of shop rate labor, defeating my intent to rebuild and learn on, I left FRUSTRATED and feeling conned. I went back a week later with my triple and forks and was told they were good.  I ended finding another frame with an Alberta title, stripped all the parts off my "bent" frame and stuffed it into the attic until today. Re-assembled the parts onto the new frame and got riding.

I don't want to scrap this frame so here's what I did. Not very scientific but it was my first test.
Flipped the frame on its back, leveled it, found center on the back cross member as pictured.   

Framing square against tube


Second test. Drew a straight line on the floor. Frame upright, leveled, plumb bob at the rear and plumb bob hanging from the steering stop. Plumb front to back along the straight line.  I place a straight edge down the steering tube and noted where the straight edge touched the line. The picture tell the tale. 

Is my method flawed and is this not conclusive enough?  Let me know your thoughts.
Various photo's different angles.

[lwahples]

Wow,you spent money to have them say it's off.But would only say where if you spent more?Hard to believe it's bent with all the tests that you did.

[LesterPiglet]

I would guarantee your floor isn't flat.

[Jay Ace]

I would guarantee your floor isn't flat.

Isn't that what the level was for?

[albertaboy]

I would guarantee your floor isn't flat.

Isn't that what the level was for?

My mind is open for suggestions.  Keep them coming.

When I bought this bike, I got a 30 minute test ride.   Nothing about it's handling scared me-nothing like my modern bike mind you and given it's age nothing seemed off. I also have 35 years street riding experience- still Im no pro.

[LesterPiglet]

Be better suspending the frame and putting the level across the flat behind where the seat/tank meet and use plumb lines.

[brooze72]

Maybe my eyes or the pictures are decieving me, but it doesn't seem to be showing that it is out by 3/4"?  I am curious about the first "string test", was that a wheel alignment check?

[albertaboy]

Maybe my eyes or the pictures are decieving me, but it doesn't seem to be showing that it is out by 3/4"?  I am curious about the first "string test", was that a wheel alignment check?

Wow,you spent money to have them say it's off.But would only say where if you spent more?Hard to believe it's bent with all the tests that you did.

Yes, I believe the sting test is the common wheel alignment test. Shop 1 claimed it was accurate as an initial test and they failed the bike based on that.
Ya, the OOP inspection is a service they get a fee for. No charge to re-inspect and "pass" after recommended repairs have been done. I don't tend to believe people lie to just grab money for un necessay repairs but neither shop left me feeling very confident.  Regardless, I cant title the frame without a passing OOP inspection.

[albertaboy]

Be better suspending the frame and putting the level across the flat behind where the seat/tank meet and use plumb lines.

I will try that and see what I come up with.  Thanks.

[brooze72]

. If they described it as "out 3/4"" are they describing the track of the front wheel compared to the rear? If so, many factors could account for that which have nothing to do with the frame itself. Spacers, swing arm bushings, head stock bearings, etc...

If your latest examinations of the frame only, you'll be hard-pressed to identify the true cause without the wheels installed and the swing arm, forks etc. if a visual inspection of your frame doesn't reveal damage or "wrinkles" it's not likely the culprit.

That's what I was thinking too, calj737

[iron_worker]

How did you ensure the straight edge you used was in line with your steering tube? Looks like it's just laying on there. If you had a known straight tube that would fit snugly in the steering tube then that would work well.

IW

[albertaboy]

Might be my eyes too, but it seems you've determined your frame is plumb, not square. If they described it as "out 3/4"" are they describing the track of the front wheel compared to the rear? If so, many factors could account for that which have nothing to do with the frame itself. Spacers, swing arm bushings, head stock bearings, etc...

If your latest examinations of the frame only, you'll be hard-pressed to identify the true cause without the wheels installed and the swing arm, forks etc. if a visual inspection of your frame doesn't reveal damage or "wrinkles" it's not likely the culprit.

Don't know if any of that helps... But maybe reassures you that you're not crazy.

I think my test shows the steering tube is as it's supposed to be.  What spacers do you refer to?? the end caps on the swing arm?

Both shops questioned the and checked the swingarm for end caps but the PO had replaced the bushings and the axle collar with new honda OEM parts.  I could verify this with the new parts receipts the the actual old parts as provided by the PO.  Both questioned if the problem was at the triple tree.

If the spacers you refer to are the wheel axle spacers?? I'll have to research but I think I've got the right ones, front and back but I cant be sure.

Otherwise, I cant not see any obvious frame damage or wrinkles.

Basically, My next step is to install roller bearings in the steering stem, install a complete front end, install the swing arm, check the axle spacers and then do an alignment test???

[lucky]

This story is a mess from the very beginning. I feel sorry for you that you could not get the help that you needed.

You cannot measure the frame the way you are showing in the photos
The level across the bottom of the frame means nothing.
Many motorcycles that have double loop cradle frames have one side of the frame lower than the opposite side.

What matters is the rear axle alignment in relation to the steering head and the swing arm pivot points being level to the ground etc.,.

First you must find someone that builds chopper frames.
Have them put the frame in their jig.

The way it works is that the STEERING head is put into the fixture with a cone on the top and the bottom. and it is tightened up.
Then measurements can be made along the centerline of the frame and the swing arm centerline..

I feel that you were totally ripped off for $190.00!! AND they could not even tell you what is bent? WOW.

Photos coming.In the photos below you can see how the centerline is established.

For $190.000 I could tell you exactly what was going on with your frame.
I do not need a lazer either.
Lazer is too fuzzy and not exact marking.

Just find a chopper builder that has a motorcycle frame building fixture.
Easy Peasy.

If a frame was 3/4 inch off it would have noticeable visual damage.
Wrinkles or paint flaking off near welds, broken welds etc.,.
I still  do not know how those people stay in business. Cheeeeessshhhh!!!

I build frames from scratch. I know what I am talking about.
BTW...Many factory frames are slightly off.

[albertaboy]

This story is a mess from the very beginning. I feel sorry for you that you could not get the help that you needed.

You cannot measure the frame the way you are showing in the photos

First you must find someone that builds chopper frames.
Have them put the frame in their jig.

The way it works is that the STEERING head is put into the fixture with a cone on the top and the bottom. and it is tightened up.
Then measurements can be made along the centerline of the frame and the swing arm centerline..

I feel that you were totally ripped off for $190.00!! AND they could not even tell you what is bent? WOW.

Photos coming.

Oh I felt like I was totally bent over and they didnt even use spit.... sorry if that's to graffic...Anyways.   Their fee included checking the tires, brakes, fork seals, head, tail signal lights ect etc. You know... safety stuff that takes specialize techs in the eyes of the government at least, stuff that you and I can't possibly see.  I wanted to be careful not to turn this into a dishonest service center rant but I couldnt believe it when shop 2 told me, despite the lazer, they still couldn't determine a bend.

So having said that, I prefer to believe the shops are honest with a reputation to uphold so maybe the wheel spacing on the axle or steering stem bearing were buggered??? 

Regardless, I like the chopper builder idea. There must be somebody around this small town of a million people.

[lucky]

Be better suspending the frame and putting the level across the flat behind where the seat/tank meet and use plumb lines.

Those sheet metal stampings for the seat and so forth are often not right.
All measurements on a frame are in relationship to the steering head of the motorcycle frame.

[lucky]

If you really wanted to do this right, you will need a flat table.
The table MUST be level in both directions.

Then you must have a post that can hold the steering head centered. and it MUST be vertical and level in both directions. THEN AND ONLY THEN can you start making any measurements.

[lucky]

Yes, I can imagine that.
Some double loop cradle frames have a removable section for engine work.
Those are often not symetrical.

[heffay]

Take the bike up next to a large tree, fence or wall, and smack the front wheel into the structure until it's square.   

old bmx trick should be good enough for the inspection, right?   

[albertaboy]

Take the bike up next to a large tree, fence or wall, and smack the front wheel into the structure until it's square.   

old bmx trick should be good enough for the inspection, right?   

Haha, I like your sense of humor.... Its true, as a kid on the farm, we used to sneak our dirt bikes a few miles to the local gravel crusher/pit and and climb the walls. Didn't always make it to the top and the tumble to the bottom surely bent something. My bike's front end was so far off it wasn't funny... still rode the hell out of it.

[albertaboy]

This story is a mess from the very beginning. I feel sorry for you that you could not get the help that you needed.

You cannot measure the frame the way you are showing in the photos

First you must find someone that builds chopper frames.
Have them put the frame in their jig.

The way it works is that the STEERING head is put into the fixture with a cone on the top and the bottom. and it is tightened up.
Then measurements can be made along the centerline of the frame and the swing arm centerline..

I feel that you were totally ripped off for $190.00!! AND they could not even tell you what is bent? WOW.

Photos coming.

Oh I felt like I was totally bent over and they didnt even use spit.... sorry if that's to graffic...Anyways.   Their fee included checking the tires, brakes, fork seals, head, tail signal lights ect etc. You know... safety stuff that takes specialize techs in the eyes of the government at least, stuff that you and I can't possibly see.  I wanted to be careful not to turn this into a dishonest service center rant but I couldnt believe it when shop 2 told me, despite the lazer, they still couldn't determine a bend.

So having said that, I prefer to believe the shops are honest with a reputation to uphold so maybe the wheel spacing on the axle or steering stem bearing were buggered??? 

Regardless, I like the chopper builder idea. There must be somebody around this small town of a million people.

Just got off the phone. Only two chopper builders here an neither build their own frames. They prefer to buy frames that are already certified and passed inspection. The one guy described "the hassle" wasn't worth building their own.

[754]

 Will look over this later, will. Say this though you can probably do it anywhere but just level off the motor mount rear that is or swingarm mount.

[albertaboy]

Alberta - look at pic 3 you posted: did you by chance hold a second level at 90 to the one laying across the top? I'd be curious with the plumb bob, steering and center of frame all "lined" up, whether the frame is racked vertically?

From the picture (#3) it looks like the rear fender/seat brace is off center. May simply be the angle of the photo, but use that setup and measure the center AT&T he rear, line up as you have the steering head, then measure vertically for 90. Just confirm its a photo anomaly and not that the rear seat hoop area is racked over.

No, I did not hold a level at 90.  I could mock it up again easily. Might go back out tonight anyways.
Picture 3 is just the angle.
I've a second frame almost stripped bare except for the wiring and I've spent at lot of time comparing the two without being able to spot a problem. But the naked eye is so deceiving.  I'm going to put in tapered bearing races into the steering tube, mount a triple, forks and wheels, put a swingarm in mount a  rear wheel and do some of the checks suggested here.  I likely dont have a grasp where to begin checking once I do this so I'll come back with more questions and photos and get your guidance.

Thanks everyone so far. Your input and suggestions were greatly appreciated.  Stay tuned for follow up on this later.

[Kickstart]

I don't have any experience with this... but I'll throw in my two cents

I think you need to find out exactly what the test procedure was that the shops did. What specifically did they measure? 

Also:
Did they do these measurements on the bare frame... without the swingarm installed?  I believe the frame sometimes gets pulled in a little when the engine and swingarm are bolted in... so if one side "springs" out some more than the other I could see how this might cause an out of alignment measurement on the bare frame.

[albertaboy]

I don't have any experience with this... but I'll throw in my two cents

I think you need to find out exactly what the test procedure was that the shops did. What specifically did they measure? 

Also:
Did they do these measurements on the bare frame... without the swingarm installed?  I believe the frame sometimes gets pulled in a little when the engine and swingarm are bolted in... so if one side "springs" out some more than the other I could see how this might cause an out of alignment measurement on the bare frame.

Hey
Thanks.  I'm kinda starting over now, trying to see if this frame is bent or not. Back in 2010 when I took the bike in for the OOP test, it was a complete running bike.  I since have stripped all the parts off of it onto a second frame and got riding. Now I want to make sure this frame isn't useable before I cut it up or otherwise. 

[albertaboy]

This is where I got to tonight.  Same wheels, same swing arm, same triple and top clamps except upgraded to tapered roller bearing, same axles, same wheel spacers, new cycle x fork uppers, same fork lowers. Shouldnt matter about the upper fork tubes as they checked out straight.  Am too tired to go on now and much more reading to do to check it's alignment.  I need to double check I tighten properly here and there.  Will it matter there's no engine???