Narrow and wide frames on 750s

PeterJansens

PeterJansens

Junior member
Location
Netherlands
I know there are narrow frames and wide frames for 750s but that's about the extent of my knowledge. Can anyone please enlighten me, or point me to website that helps?
I am particularly interested to find out if any seat will fit any frame without a problem?
 
PeterJansens said:
I know there are narrow frames and wide frames for 750s but that's about the extent of my knowledge. Can anyone please enlighten me, or point me to website that helps?
I am particularly interested to find out if any seat will fit any frame without a problem?
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Wide frames concern only the early GT, the type with the wide lower rear engine plates and the nice rounded rear frame down tubes.
So, seats for wide frames are only the early GT, and 650, ones.
Otherwise, all seats are interchangeable, to my knowledge.
Paul
 
Mine is number 1460, the Dutch registration (mid '68) says 750 GT , what do they know ;)
Paul, how to "identify" those nice rounded rear frame down tubes?
 
PeterJansens said:
Mine is number 1460, the Dutch registration (mid '68) says 750 GT , what do they know ;)
Paul, how to "identify" those nice rounded rear frame down tubes?
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Here we have a photo of the down tube on the first type of frame, known as wide type. Notice the wide rear engine mounting.
The evolution of the frames over the years involved tucking the engine in with shorter mounts to gain rigidity. And putting a brace across the swing arm.
Peter, if you have a decent wide type seat for sale or swap, I'm your man.
Paul
1721810172994.jpeg
 
On the early frames you still see what frame design Massimo took as a starting point: Norton’s featherbed frame, the reference at that point in time.

Marnix
 
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Paul Marx said:
Here we have a photo of the down tube on the first type of frame, known as wide type. Notice the wide rear engine mounting.
The evolution of the frames over the years involved tucking the engine in with shorter mounts to gain rigidity. And putting a brace across the swing arm.
Peter, if you have a decent wide type seat for sale or swap, I'm your man.
Paul
View attachment 91298
Click to expand...
Ah! Then mine has a wide frame indeed, thank you my friend.
The lack of a decent seat for it started my query to begin with, so sorry but no i dont have ....
 
Only ever had later GTs.
GT has shorter tank & longer seat compared to SF.
GT rear top seat/guard frame loop is longer.
 
rez said:
Framenumber 2833 upwards
are the small Frame.
All before should be the wide Frame.

Regards
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This fits with my 1969 GT (VIN: 2763), which has a 16cm gap between the seat tubes where the metal tongues that hold the seat in place are.

I seem to recall something being said about the wide frame not handling as well as the later narrower frame but from riding both I'm damned if I can genuinely tell any difference.
 
general_piffle said:
This fits with my 1969 GT (VIN: 2763), which has a 16cm gap between the seat tubes where the metal tongues that hold the seat in place are.

I seem to recall something being said about the wide frame not handling as well as the later narrower frame but from riding both I'm damned if I can genuinely tell any difference.
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Depends how you ride.
The handling becomes more accurate until the final SF1/2 type frame. The frame progressively got nearer the engine and as it did, handling became more precise. Not to mention the brace across the swing arm behind the engine. The swing ram was more flexible before that.
When I ride my S after my SF2, I feel as though I'm perched higher up.
The disc brake SFC is another world altogether. Low and rigid.
Paul
 
Paul Marx said:
Depends how you ride.
The handling becomes more accurate until the final SF1/2 type frame. The frame progressively got nearer the engine and as it did, handling became more precise. Not to mention the brace across the swing arm behind the engine. The swing ram was more flexible before that.
When I ride my S after my SF2, I feel as though I'm perched higher up.
The disc brake SFC is another world altogether. Low and rigid.
Paul
Click to expand...
The GT with its super wide high bars and low torque/grunt seems most at home lazily chugging out of bends as you roll on the throttle, not hard, but it’s brisk enough. Especially considering I’m still running it in, so staying below 4k. But even then, just from the way the bike is, I can’t imagine I’ll venture much above that for prolonged periods.

When I think about it in comparison to my SF the GT is a lot more relaxed in every way. But just as much fun, in a different way.
 
MarnixSFC said:
On the early frames you still see what frame design Massimo took as a starting point: Norton’s featherbed frame, the reference at that point in time.

Marnix
Click to expand...
Interesting! I wonder how close the early ‘wide’ Laverda frames were to the featherbed?

Because these were known for their sweet handling. The most developed ‘home brew’ sports motorcycle back in the day being the Triton. A mix of what was considered the best handling frame (Norton featherbed) with the best performing Triumph engine.
 
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