frame straightness

Hi all,
I have posted a few times about my bike build which is a Norton 850 mk11 bitsa and I'm back for a it more wisdom if anyone would ne kind enough to help. I have had my frame straightened and powder coated by a reputable frame repair shop twice now. First time it came back with a bent swing arm, took it back and had it fixed, then the head steady mount was out of alignment. This was very much to the repairers surprise, he then re-straightened the frame for free and paid to have it powder coated again.
I got the bike back to a rolling chassis again only to realise the rear wheel is not plumb (out by about 4-5mm with the main frame all levelled and plumb). To me this isn't right as it should all line up, I have put straight edges all over the frame, the main top tube has around a 3-4mm bow up and the bars on the left hand side which the side covers sit between also have slight bows outwards. But the question is should I just try and live with this, is it normal to see bike frames like this getting around? were they straight out of the factory? am i being to pedantic about this? I have never owned a Norton before so I'm kind of coming in cold. The other option I'm considering is a brand new frame at around $2000 Aus which I really don't want to do as I have put a lot of cash into this bike already. Here's a few photos which hopefully help explain what I'm talking about, and yes I know the shocks are on upside down in one of the photos. Any feed back will be much appreciated, cheers
photo 1- level across the frame
photo 2- close up of the bubble
photo 3- level against the wheel
photo 4 - gap when level is plumbed against the wheel

sorry about the photos i cant figure this photo bucket thing out

Unfortunately, you need to use a different photo hosting service since Photobucket pulled the plug on free 3rd party hosting.

morton said:

the head steady mount was out of alignment.

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Could you give more details on what was done?

how annoying.... if you are in the NOC there was a uk specialist who you used to advertise in roadholder...

Sure, the guys method is putting the full rolling chassis on his jig he puts a pole through the head tube and uses string lines to check for straightness. When I got the frame back the second time he had heated the vertical tubes coming from the head tube hear the junction and then down near the isolastics mounts. He had also heated three points on all bars which surround the side covers and then done whatever he had to to get it straight (or so he thought).

morton said:

Sure, the guys method is putting the full rolling chassis on his jig he puts a pole through the head tube and uses string lines to check for straightness. When I got the frame back the second time he had heated the vertical tubes coming from the head tube hear the junction and then down near the isolastics mounts. He had also heated three points on all bars which surround the side covers and then done whatever he had to to get it straight (or so he thought).

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The frame and swinging arm may well be dead straight now, but the engine cradle and swinging arm are still basically held suspended by the Isolastic rubbers so the cradle assembly could potentially be out of alignment with the frame especially if the cylinder head is being pulled over to one side, that's why I asked what you meant by the head steady mount being out of alignment as the engine cradle/cylinders/head are offset 1/8" - 3/16" left of the frame centre line and there's 1/8" offset deliberately built into the actual head steady bracket.

Thanks for the feedback, I think I mis interpreted your forst question. When I got the frame back from the first straightening the head steady bracket was probably about 8mm out of line (left to right when standing over the bike). After round two the head steady bracket now lines up with the isolastics rubbers fine. Its kond of hard to describe just with words but after putting levels and straight edges everywhere it does seem as though the cradle is out of alignment but I just can't quite pin point where is coming from.

Can you take it, as is, back to the frame straightener and ask him his opinion?
Hopefully he won't say he needs to bend the swing arm back the way it was to get the rear wheel plumb.
That would be crazy making.

Stephen Hill

morton said:

Thanks for the feedback, I think I mis interpreted your forst question. When I got the frame back from the first straightening the head steady bracket was probably about 8mm out of line (left to right when standing over the bike). After round two the head steady bracket now lines up with the isolastics rubbers fine. Its kond of hard to describe just with words but after putting levels and straight edges everywhere it does seem as though the cradle is out of alignment but I just can't quite pin point where is coming from.

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Does slackening the head steady alter the amount of misalignment?
Is the cradle parallel to the frame and what is the offset dimension (difference in the cradle to lower frame tube measurement on both sides divided by 2)?
Could the cradle be twisted?
If the frame is set vertical, and the Iso mounting bolt and stud are exactly horizontal, the head steady isn't pulling the cylinders/head over to one side and the cradle is parallel to the frame then the apparent vertical misalignment at the rear wheel seems to point to the cradle or Iso. rubbers being at fault.

If you have the tank off and look straight downwards from the maintube , you can see the head will be to the left-side a little bit. That's normal. :shock:

morton said:

sorry about the photos i cant figure this photo bucket thing out

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Easy, don't use Photobucket!

I think either the cradle is still goofy or the swingarm is not right. A very remote possibility is that one or both of the slots for the axle in the SA are egged out, permitting the axle to go off plumb. There shd be no chance at all to wiggle the axle up and down if placed through the slots. My money is on the swingarm; one of the arms has to move up in relation to the other.
What does he say when you show him the wheel problem?

Do you know how the frame got bent in the first place ? The top tube being humped up is kind of normal. The angle braces should be straight. The shop manual has dimensioned drawings for the 850 frame.

To check the swingarm put some straight rods through the slot for the axle and the hole for the swingarm pivot. Are they parallel ? Put the rods through the isolastic mounts on the main frame. Are they parallel ? Install the cradle and swingarm. Put the rods through the slot for the axle and the front isolastic mount. I think you can see where this is going.

It is harder to judge where the steering head should be pointed, but it should line up with the middle of the frame. I drilled out a couple big threaded knobs, big enough to sit in the (oops, I'm running tapered roller bearings in the head stock)... Stick a straight rod through the steering head bearings. It works best if it a good fit. If you turn the rod and it makes a circle, the center of the circle should be along the centerline of the frame.

All this is not going to get you the worlds straightest Norton but you should be able to tell what's bent. I worked through steps like these and straightened the frame on my 750. It is not perfect, but it is much much better.

Greg

Check this out!

http://www.vintagenet.us/phantom/wsc.html

Success straightening thing out!

morton said:

Hi all,
I have had my frame straightened and powder coated by a reputable frame repair shop twice now.]

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The alarm bells rang when you said 'twice' :shock: Not so reputable frame repair shop now!

I wonder when we see posts in the forum about isolastic mounts not lining up if it is in fact that an aftermarket headsteady has been installed an not properly aligned, causing the whole engine and cradle to be cocked in the frame.

Russ

The frame got bent when my dad decided to punt it down the road at speed about 30 years ago, apparantly it flipped over a few times. I took the project on a year or so ago and most of the bike is damaged. The swing arm is straight and in wind, checked off the bike with a straight bar through the axel tabs and spindle. The whole cradle is out of level, I checked both the isolastics tube ans swing arm spindle tube and they are out of level on the same plane (this is what I tried to show with my failed photos). After reading the article about the worlds straightest norton it seems as though there is a lot to getting these frames perfect. I'm guessing from these replys that a rear wheel out of plumb is definitely a concern and not to be excused because of the bikes age? As far as for the frame repairer I have not taken it back or even contacted him as I have been a bit to upset about it and don't want to do anything rash. This guy has been doing this stuff for ever and has a great reputation so I am genuinely surprised. He did have a theory that perhaps if there is stress in the frame it may be relaxed when poweder coating (heating) resulting a bent frame again. Unfortunately I was a bit naieve and didn't check everything before getting it coated again.

morton said:

This guy has been doing this stuff for ever and has a great reputation so I am genuinely surprised. He did have a theory that perhaps if there is stress in the frame it may be relaxed when poweder coating (heating) resulting a bent frame again. Unfortunately I was a bit naieve and didn't check everything before getting it coated again.

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Powdercoating is only about 400˚F so not super hot. But might be enough to adjust the metal.

You should be able to post photos by clicking on the "add image to post" link in the bottom left of the typed field. Photos always seem to help with discussions like this. It is hard to know when to throw away a frame and start over. Is there another frame shop in your area that you can get advice from? Where do you live? Instead of buying a new frame you might be better off finding a good used frame.

Russ

I have not taken it back or even contacted him as I have been a bit to upset about it and don't want to do anything rash

Yeah, just take some deep breaths and go back there. It's not the end of the world. Don't get angry or piss the guy off; he still has what you don't have, what you need, and what you've paid for: the equipment and expertise to make it right or declare the frame too far gone. Unless you turn into a jerk, and if he's as good as you say, he's not likely to blow a good reputation just because things didn't go to plan.
Crap happens, yes?
And when you pick it up, I suggest you don't even leave the place until he shows you that everything is done to your satisfaction.

a rear wheel out of plumb is definitely a concern and not to be excused because of the bikes age?
Keeping in mind that the wheel (and the level, for that matter) is not perfect, correct.