Frame indention ?
- spdygon
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Frame indention ?
09 Nov 2015 07:13
New to me is another 76kz900. It came with a Vettet front fairing . Bike is all apart and ready to sent to powder coat but would like your opinion .
When fairing was installed ...looks like the bottom u bolts were over tight in and made a indention on the frame tube if repair is needed ...What should be done.
When fairing was installed ...looks like the bottom u bolts were over tight in and made a indention on the frame tube if repair is needed ...What should be done.
1982 GS1000sz Katana ( #15...17K Miles)
1982 GS1000sz Katana ( # 297....7100k Miles)
1978 Kz1000 Z1R. 10K Miles1
1978 kz1000 z1r 27k miles
1977 KZ 1000 A ( Project ) 54K Miles
1976 Kz900A4 (Red)21K miles
1976 Kz900A4 ( Red)7500 miles
1974 Z1 900 project
1982 GS1000sz Katana ( # 297....7100k Miles)
1978 Kz1000 Z1R. 10K Miles1
1978 kz1000 z1r 27k miles
1977 KZ 1000 A ( Project ) 54K Miles
1976 Kz900A4 (Red)21K miles
1976 Kz900A4 ( Red)7500 miles
1974 Z1 900 project
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- Tyrell Corp
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Re: Frame indention ?
09 Nov 2015 07:37
Assuming this is cosmetic and won't affect the frame strength significantly, I'm thinking maybe braze or building up the dent with weld then smoothing? I prefer paint for frames so I'd use plastic filler.
Must have taken some serious force to dent the tube like that, short of cutting and shutting new tube sections in there I' not sure what the other options are?
Must have taken some serious force to dent the tube like that, short of cutting and shutting new tube sections in there I' not sure what the other options are?
1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces
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- punisher11b
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Re: Frame indention ?
09 Nov 2015 07:52
Depends a lot on the geometry of the dent and the stress at the location but I would be careful. while round tubing is very strong, it loses a significant amount of strength when creased. Just a word of caution.
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- Tyrell Corp
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Re: Frame indention ?
09 Nov 2015 08:26 - 09 Nov 2015 08:27
Depends a lot on the geometry of the dent and the stress at the location but I would be careful.
I guess the question being, the strength of a tube is a function of it's diameter and wall thickness, will a small deflection here be signifiicant, or are there other metallurgical factors that may have weakened it to consider?
It never ceases to amaze me how ham fisted some PO's are...surely the U bolts would be rubber mounted anyway for a fairing?
I guess the question being, the strength of a tube is a function of it's diameter and wall thickness, will a small deflection here be signifiicant, or are there other metallurgical factors that may have weakened it to consider?
It never ceases to amaze me how ham fisted some PO's are...surely the U bolts would be rubber mounted anyway for a fairing?
1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces
Last edit: 09 Nov 2015 08:27 by Tyrell Corp.
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- punisher11b
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Re: Frame indention ?
09 Nov 2015 09:06 - 09 Nov 2015 09:11
The main factor is now that it's creased it has an increased crack propagation risk in the direction of the crease, the bar is no longer round so it is no longer "strong in all directions". The short of it, if it's mostly superficial your probably OK. If it's not, the deeper the crease the more I would worry. The reason I posted/ what worried me is that creases can cause round tube to fail suddenly when the crease is really bad. In the end it's a judgment call depending on factors like location, and crease position relative to applied stress.
It seriously is amazing how badly some people need a test before they are allowed to buy a wrench! :lol:
It seriously is amazing how badly some people need a test before they are allowed to buy a wrench! :lol:
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Last edit: 09 Nov 2015 09:11 by punisher11b.
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- Kidkawie
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Re: Frame indention ?
09 Nov 2015 10:48 - 09 Nov 2015 10:48
Clean off all the paint, fill with weld, blend, repaint. Move on.
1975 Z1 900
1994 KX250 Supermoto
2004 KX125
1994 KX250 Supermoto
2004 KX125
Last edit: 09 Nov 2015 10:48 by Kidkawie.
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- punisher11b
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Re: Frame indention ?
09 Nov 2015 11:13 - 09 Nov 2015 11:13+1Kidkawie wrote: Clean off all the paint, fill with weld, blend, repaint. Move on.
Then you don't have to worry

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Last edit: 09 Nov 2015 11:13 by punisher11b.
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- missionkz
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Re: Frame indention ?
09 Nov 2015 11:26 - 09 Nov 2015 11:27
Boy, I don't know but a few really good race car builder friend of mine told me welding on a motorcycle frame like this is best served by annealing the entire frame after welding.
I'd be talking to someone about sleeving that spot and filling somehow.
I'd be talking to someone about sleeving that spot and filling somehow.
Bruce
1977 KZ1000A1
2016 Triumph T120 Bonneville
Far North East Metro Denver Colorado
1977 KZ1000A1
2016 Triumph T120 Bonneville
Far North East Metro Denver Colorado
Last edit: 09 Nov 2015 11:27 by missionkz.
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- Tyrell Corp
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Re: Frame indention ?
09 Nov 2015 13:38
Clean off all the paint, fill with weld, blend, repaint. Move on.
+1 Mission. this is what i was hinting at with the metallurgical aspect which I'm not sure about.
+1 Mission. this is what i was hinting at with the metallurgical aspect which I'm not sure about.
1980 Gpz550 D1, 1981 GPz550 D1. 1982 GPz750R1. 1983 z1000R R2. all four aces
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- punisher11b
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Re: Frame indention ?
09 Nov 2015 13:52 - 09 Nov 2015 13:54
It is a good point to be made, that it will become more brittle when welded. If the metal is already of a harder nature then not only do you want to be careful in how you fix it, but makes the crease more dangerous as well. However, it may not be that bad considering it wouldn't be a full penetration weld.

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Last edit: 09 Nov 2015 13:54 by punisher11b.
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- 80B4
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Re: Frame indention ?
09 Nov 2015 14:06
Inspect the area around the indentation for cracks. If there are none, leave it alone. You will do much more harm trying to fill that small flaw with weld then you will do good. Keep an eye on that area but you won't have any problems.
I worked in the Vetter design studio. The mount for a Vetter fairing is designed to be held on with hose clamps. Using U blots is a kludge.
I worked in the Vetter design studio. The mount for a Vetter fairing is designed to be held on with hose clamps. Using U blots is a kludge.
1980B4 1000
1978 Z1R
1978 B3 750
1978 Z1R
1978 B3 750
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- SWest
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Re: Frame indention ?
09 Nov 2015 14:33
I had a Vetter fairing on mine with U bolts and that didn't happen. My crash bar has them too. How the PO did it I have no idea. The U bolts would snap before that. Maybe a crash?
Steve
Steve
Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229
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