Removing the gusset plate, down sides? Tips?

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Fast Eddie

Fast Eddie

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I need to remove at least some of the gusset plate.

I know some of you fine fellows have done this before, so wanted to ask for any hints n tips.

From a design perspective, what is it there for in the first place? And is there any down side to removing it?

Is there a sensible way of doing it, ie leaving enough in place to still provide support (or whatever it’s there for) etc.

I know it’s a fairly simple mechanical job, and I’m probably over thinking it, but I just wanted to ask before I sharpen the axe and start swinging…
 
Fast Eddie said:
I need to remove at least some of the gusset plate.

I know some of you fine fellows have done this before, so wanted to ask for any hints n tips.

From a design perspective, what is it there for in the first place? And is there any down side to removing it?

Is there a sensible way of doing it, ie leaving enough in place to still provide support (or whatever it’s there for) etc.

I know it’s a fairly simple mechanical job, and I’m probably over thinking it, but I just wanted to ask before I sharpen the axe and start swinging…
Click to expand...
Hi FE. What plate is this?

Ed
 
If you mean the one at the back of the carbs that twixes the frame and top tube?
Then it can be removed completely
My frame doesn't have one
It was removed by a previous owner
All I did was tidy it up with a linnisher because it looked like it had been removed by a fireman
I welded a couple of lugs on to hold the side panel and oil tank
Cheers
 
I’m referring to the main gusset plate at the rear of the top spine, as Baz refers to.

Thanks for the reassurance Baz. I can see that removal is quite straightforward given a couple of hours and an angle grinder.

Now I’m looking at it and thinking ‘yes, but why did Norton put it there in the first place’?
 
Probably to stabilise that part of the frame
Somewhere to hang the oil tank/panel from
Stop people fitting a Webber etc etc
 
baz said:
If you mean the one at the back of the carbs that twixes the frame and top tube?
Then it can be removed completely
My frame doesn't have one
It was removed by a previous owner
All I did was tidy it up with a linnisher because it looked like it had been removed by a fireman
I welded a couple of lugs on to hold the side panel and oil tank
Cheers
Click to expand...

Whatda mean Baz, I was a fireman for 30 years and was a damn good gusset plate remover :)
 
Sam's favourite tool ;) ....

Removing the gusset plate, down sides? Tips?
 
The gusset looks to act as a stiffener between the diagonal tubes. The tubes fold in at that level so if there is any decent tension or compression load in the tube in the absence of the stiffener it will put some bending stress in the tube due to the fold, and result in some flex.
Given that the frame design will likely have been by hand, or eye, it may have been there as good practice rather than strictly necessary.
Structural engineer here, not mechanical, but it looks a more robust detail with the gusset in place so if it were me i would try to avoid removing it. Thats just a seat of the pants opinion though.
 
I'm currently running an S.U. carb, they are tall and that gusset is very close to the dashpot, so I have wondered about removing it as well.

I did think about putting a gusset on each side like this if I remove it. I don't think it will clash with anything. Any thoughts?

Removing the gusset plate, down sides? Tips?
 
ntst8 said:
The gusset looks to act as a stiffener between the diagonal tubes. The tubes fold in at that level so if there is any decent tension or compression load in the tube in the absence of the stiffener it will put some bending stress in the tube due to the fold, and result in some flex.
Given that the frame design will likely have been by hand, or eye, it may have been there as good practice rather than strictly necessary.
Structural engineer here, not mechanical, but it looks a more robust detail with the gusset in place so if it were me i would try to avoid removing it. Thats just a seat of the pants opinion though.
Click to expand...
Yeah… we might wear similar pants!

I know it’s been done, and frames haven’t fallen apart, so I’m into the realms of over thinking it. But when I do it I’ll probably see if there’s a way of only removing what’s necessary and leaving enough behind to put my mind at rest.

I haven’t had a proper close look at that yet though.
 
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cliffa said:
I'm currently running an S.U. carb, they are tall and that gusset is very close to the dashpot, so I have wondered about removing it as well.

I did think about putting a gusset on each side like this if I remove it. I don't think it will clash with anything. Any thoughts?

View attachment 82845
Click to expand...
That’s an interesting idea, and could also provide something to hang the oil tank and side panel from…
 
Fast Eddie said:
Yeah… we might wear similar pants!

I know it’s been done, and frames haven’t fallen apart, so I’m into the realms of over thinking it. But when I do it I’ll probably see if there’s a way of only removing what’s necessary and leaving enough behind to put my mind at rest.

I haven’t had a proper close look at that yet though.
Click to expand...
I would keep any cutting to a minimum if you can
My frame had already been done many years before I bought the bike
But if I were doing it from scratch I would only cut it if I needed too
The extra space came in handy when I fitted the TM 40 mik
So why do you want to cut it?
 
Nigel,
Are those 35mm FCRs too small now? With the gusset plate removed there might be room to fit a pair of 2" SUs.:)
 
Matchless said:
Nigel,
Are those 35mm FCRs too small now? With the gusset plate removed there might be room to fit a pair of 2" SUs.:)
Click to expand...

Years ago I had manifolds made to fit a twin webber carb to a Commando, never got round to it unfortunately
 
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