Author Topic: Can you cut the Center-stand cross tube out of the frame?  (Read 4287 times)

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Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #25 on: January 17, 2011, 05:16:02 PM »
Egli and Martin, just to name a couple, {there's heaps more} Raced many bikes successfully using the engine as a stressed member in the frame. Forum member "Mec" has built a beautiful example of this and races it......I can't see any problems with it as these bikes have been around for almost 40 years....

Mick
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Offline Kong

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #26 on: January 17, 2011, 06:05:24 PM »
If some of you guys who are racing these frames are reinforcing this area I would very much appreciate it if you would provide a photograph of just what you are welding in where, because I can not see just what it is that needs to be strengthened in this area.

I have to say, I find it odd that if this is being done regularly, and it seems that some folks find it a necessary modification, then why after searching through many many postings and doing hundreds and hundreds of searches both here and elsewhere this is the first time anyone has mentioned it.  If it is true that you not only can not remove that tube (and I doubt that I'm the first person who has dared dream such a thing) but that in fact that area of the bike needs considerable reinforcement for the bike the handle nicely, well, that's the sort of thing that you'd then expect to be common knowledge.  Why ain't it?

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Offline BobbyR

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #27 on: January 17, 2011, 06:08:06 PM »
I think Paulages did a tread on frame stiffening. He welded steel into various areas.
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Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #28 on: January 17, 2011, 06:13:23 PM »
If some of you guys who are racing these frames are reinforcing this area I would very much appreciate it if you would provide a photograph of just what you are welding in where, because I can not see just what it is that needs to be strengthened in this area.

I have to say, I find it odd that if this is being done regularly, and it seems that some folks find it a necessary modification, then why after searching through many many postings and doing hundreds and hundreds of searches both here and elsewhere this is the first time anyone has mentioned it.  If it is true that you not only can not remove that tube (and I doubt that I'm the first person who has dared dream such a thing) but that in fact that area of the bike needs considerable reinforcement for the bike the handle nicely, well, that's the sort of thing that you'd then expect to be common knowledge.  Why ain't it?

Pictures please?

There are lots of posts mentioning these mods to the frame and in racing circles these mods are common. I have been bracing frames or had frames for these bikes braced since the early 80's. The bracing goes in between the frame rails that have the rear engine mounts on them, behind the oil tank, also small triangles in the junctions of the rear frame on both sides, the front of the frame gets reinforced as well. These mods are not really necessary for the street unless you ride hard, thats when the benefits of these mods can be felt. No frame tube should be removed from these bikes.....NONE....

Mick
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Offline crazypj

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #29 on: January 17, 2011, 06:26:44 PM »
I've only got pictures of Kawasaki Z1 frame with welded in braces/plates.
 This link may help though
http://www.tonyfoale.com/Articles/index.htm
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Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #30 on: January 17, 2011, 06:38:12 PM »
I've only got pictures of Kawasaki Z1 frame with welded in braces/plates.
 This link may help though
http://www.tonyfoale.com/Articles/index.htm

I have a fully braced "F" frame in my garage, i will take pics when i can...

Mick
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Offline FunJimmy

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #31 on: January 17, 2011, 06:45:46 PM »
I have a fully braced "F" frame in my garage, i will take pics when i can...

Would love to see them too.
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Offline S.c.O.O.t

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #32 on: January 18, 2011, 10:32:01 AM »
i have a CB 650 that i just cut all the tabs off but didn't cut that tube off. looked it needed to stay there so i just cleaned all the welds that hold the tabs on and called it a day . not sure if its the same on a 750 . but do u really see it when the bike is together not really.and not enough weight saving to cut it off. good luck

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #33 on: January 18, 2011, 12:34:33 PM »
If some of you guys who are racing these frames are reinforcing this area I would very much appreciate it if you would provide a photograph of just what you are welding in where, because I can not see just what it is that needs to be strengthened in this area.

I have to say, I find it odd that if this is being done regularly, and it seems that some folks find it a necessary modification, then why after searching through many many postings and doing hundreds and hundreds of searches both here and elsewhere this is the first time anyone has mentioned it.  If it is true that you not only can not remove that tube (and I doubt that I'm the first person who has dared dream such a thing) but that in fact that area of the bike needs considerable reinforcement for the bike the handle nicely, well, that's the sort of thing that you'd then expect to be common knowledge.  Why ain't it?

Pictures please?

Because Retro Rocket likes to puff up.

Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #34 on: January 18, 2011, 01:38:23 PM »
If some of you guys who are racing these frames are reinforcing this area I would very much appreciate it if you would provide a photograph of just what you are welding in where, because I can not see just what it is that needs to be strengthened in this area.

I have to say, I find it odd that if this is being done regularly, and it seems that some folks find it a necessary modification, then why after searching through many many postings and doing hundreds and hundreds of searches both here and elsewhere this is the first time anyone has mentioned it.  If it is true that you not only can not remove that tube (and I doubt that I'm the first person who has dared dream such a thing) but that in fact that area of the bike needs considerable reinforcement for the bike the handle nicely, well, that's the sort of thing that you'd then expect to be common knowledge.  Why ain't it?

Pictures please?

Because Retro Rocket likes to puff up.

A typically {and expected} stupid response from an idiot that knows sweet #$%* all about frame structure and integrity....My interest is in the safety of the guys asking the questions, not some chest beating exercise .... ::)
Do you realise how stupid your ridiculous posts are .... ::) Got anything relevant to add? didn't think so and seeing though you sell bodgey chopped up bobbers {not real ones} i find it rather interesting that you tell people that weakening a frame that is known to flex in the area of that brace, is safe , because if i took your ill advised advice and had an accident because of it, i would sue your arse for giving out dangerous information to some people that don't have the experience to know any better. I showed this thread to a couple of my riding mates yesterday and they were amazed anyone would be stupid enough to say such things, especially where the information will stay around for thousands of people to read. But this is the internet and it is full of idiots.    ::)

Kong, you can't see where it needs to be braced because the flex happens while you are riding it, its in the area behind the battery box and oil tank. You will see lots of guys cutting the seat brace off when building cafe bikes, you may have noticed the amount of guys that come into those threads saying , "i hope you are going to put some sort of brace back in its place", this is because that area of the bike already has a lot of flex, I read one thread here yesterday where the owner didn't destroy the brace and was relocating it, the same thread had the same questions about replacing the brace. I and many others here have been riding these bikes for 30+ years
Ask this question in the High Performance section for more educated responses, No offence guys but some of the info in these threads is just plain dangerous...

Mick
« Last Edit: January 18, 2011, 02:17:14 PM by Retro Rocket »
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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #35 on: January 18, 2011, 02:13:36 PM »
I didn't say to cut out the tube.  In fact, I only mentioned that many others had done just that with aftermarket frames over the years.  Your personal attacks only show those same thousands of people who you are.  Are you puffy enough yet, or do I need to lay my credentials on you?  Not that it would matter to you, but others may find it amusing who you are calling an idiot.   ;D

Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #36 on: January 18, 2011, 02:30:16 PM »
I didn't say to cut out the tube.  In fact, I only mentioned that many others had done just that with aftermarket frames over the years.  Your personal attacks only show those same thousands of people who you are.  Are you puffy enough yet, or do I need to lay my credentials on you?  Not that it would matter to you, but others may find it amusing who you are calling an idiot.   ;D

You are an idiot mate...thats all i got. You are comparing dodgey rigid frames to street bike frames that go through way more stringent tests that the pieces of #$%* you refer to. I couldn't give 2 #$%*s what your credentials are because you constantly make a fool of yourself posting stupid #$%* that is either dangerous or irrelevant. You offered an opinion that leads people to believe that the frame doesn't need that brace and then start comparing to modern sports bikes and chopper frames......lots of relevance there.?. Go post your #$%* in the high performance section and see what sort of replies you get there mate, you have also copped it in another thread on fork integrity with and without a brace. Go get your credentials mate, apart from the fact that it will make you look even more stupid, and because YOU think your intelligent doesn't make you smart, you continue to prove this on a daily basis.... ::)
I don't give a fcuk who you think i am and plenty of people here think like wise.....go check out your stupid "profanity thread" for a reality check....fool

Mick

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If You can't fix it with a hammer, You've got an electrical problem.

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #37 on: January 18, 2011, 02:37:30 PM »
Thats pretty puffy stuff.

Offline vanillagorilla

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #38 on: January 18, 2011, 02:44:34 PM »
Ooh he said puffy AGAIN!!! He's really getting you, RR...  ::)
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Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #39 on: January 18, 2011, 02:45:45 PM »
Thats pretty puffy stuff.

Excellent ;D, i didn't expect anything useful from you anyway..... ;D  Explain why you are even in this thread.?  You are now embarrassing yourself ........I post here for peoples safety and to inform, everyone can see what you are doing....another informative post dude.... ;D ;D ;D

Mick

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If You can't fix it with a hammer, You've got an electrical problem.

Offline Roach

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #40 on: January 18, 2011, 03:26:39 PM »
well now ladies play nice. ;D


back on topic

why would you cut it out. makes no sense for the amount of weight it actually is you will probably only loose about 1lb if that. the idea of weight reduction is to lighten up the bike but still keeping it rigid.

think of it this way you wouldn't go cutting out your cross-member on your car to make it handle better you go and put in a strut tower brace and risk putting an extra 1lb on the car to make it handle better. same thing goes for the centre stand mount cutting it out will only make the bike more sloppy if anything i would risk putting on another brace and make the bike maybe another 1/2 pound heavier and get my fat ass to the gym.  

« Last Edit: January 18, 2011, 03:30:50 PM by Roach »
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Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #41 on: January 18, 2011, 03:35:34 PM »
well now ladies play nice. ;D


back on topic

why would you cut it out. makes no sense for the amount of weight it actually is you will probably only loose about 1lb if that. the idea of weight reduction is to lighten up the bike but still keeping it rigid.

think of it this way you wouldn't go cutting out your cross-member on your car to make it handle better you go and put in a strut tower brace and risk putting an extra 1lb on the car to make it handle better. same thing goes for the centre stand mount cutting it out will only make the bike more sloppy if anything i would risk putting on another brace and make the bike maybe another 1/2 pound heavier and get my fat ass to the gym.  



Well i am glad this is obvious to you dude, its not physics 101 but is is commonly known where the weaknesses lie in these frames and that brace sits just in front of the swing arm pivot, anyone with half an ounce of common sense knows that removing any material from a critical part of the frame will only weaken it..... ;)

Mick
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Offline MidnightLamp

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #42 on: January 18, 2011, 04:51:26 PM »
I wouldn't cut anything out of the frame if I wasn't DAMN sure it wouldn't fall apart or crumple. Keep in mind that it's a bike, not a car....you ARE the front, side, and rear crumple zones. Leave out the last french fry from every meal, and in about 2 months you should have the same effective weight loss. Not saying it's a critical area of not, as I honestly have not taken a close look at it, but besides things like tabs...there isn't much else on a frame that isn't really there for a reason  :-\
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Offline FunJimmy

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #43 on: January 18, 2011, 06:22:06 PM »
Never a dull moment when you get KCC in one corner and RR in the other, but will they last a full 12 rounds?

Kong

I read I read a couple of threads and internet blogs on bracing frames and was quite intrigued about the whole topic.
I’m sure there is a real and measurable benefit to bracing the frame of a hard ridden bike, but felt that I probably wouldn’t be pushing my bike to those limits anyway.
I did however, weld the down tube junction to (hopefully) strengthen that part of the frame.



My vote? Listen to Mick and keep that tube and any other factory frame member where the factory put it.
Brace if you know where and believe you will ride it hard. Can’t hurt.

Cheers
FJ
« Last Edit: January 18, 2011, 08:37:27 PM by FunJimmy »
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Offline Kong

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #44 on: January 18, 2011, 09:11:27 PM »
Hell, not only am I going to leave it, I'm going out to the shed in the morning and welding gussetts around every dam tube on the thing.   ;D

Seriously, I have already welded in a pair of short tubes across the bottom of the V which will double as supports for the battery tray but more importantly to stiffen the bottom end between what I refer to to as the shock tower extension of the frame and the forward engine cradle and steering head mount.  I had already planned to put in reinforcing at each corner of the V but it was more for show than effect.

Here is my thinking.  Unless I go to the trouble you did to change the front end geometry, which I won't be doing, then my real problem is twofold.  First, recognizing that this is a street bike that will never suffer the stresses of a race bike, I would like to keep the weight at a minimum.  My method is slash and burn.  The second consideration, and while mentioned second is in truth the more important of the two considerations, is to hold the relationship between the swing-arm mount and the steering neck constant.  If I can stop that from flexing then at least the bike's handling will be consistent, maybe good, maybe bad, but it won't be like one of those old Kawasaki's, the very worst bike I have ever put under my tail.

If it will make the bike handle better I would be more than happy to go out to it tomorrow and weld gussets in at every tube juncture.  I've got plenty of plate, plenty of wire, and the electric bill is paid up.
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Offline Retro Rocket

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #45 on: January 18, 2011, 09:20:11 PM »
Just make sure that none of the gussets get in the way of anything that needs to go back in its place later....Don't ask me how i know this..... ::)

Mick
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Offline MidnightLamp

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Re: Can you cut the Center-stand cross tube out of the frame?
« Reply #46 on: January 18, 2011, 09:44:26 PM »
Just make sure that none of the gussets get in the way of anything that needs to go back in its place later....Don't ask me how i know this..... ::)

Mick

Reminds me of my first build with a twin cradle frame. I'd been so used to single downtube stressed frames (where you can literally jack up the bike, unbolt the engine and pull the damn frame away), and doing some frame welding that by this point i was getting pretty cocky  :-\. It was an old kawa, and I was helping brace the frame for a freind according to photos of a braced H1. Worked out AMAZING. Then we went decided to lift the engine out to powdercoat (it was a spare, for mockup).  :-\ 

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