GT750 Front End

Greetings. I'm working on putting a '72 Triumph Daytona together and I
needed to replace the front end. I ended up with the triple trees and forks
from a 1972 Suzuki GT750, which I managed to mount to the Triumph but it
didn't come with a wheel. I'm looking for alternatives to the original
GT750 drum brake, since I can't afford one as they seem to be favored by
vintage class racers. Does anyone know of an alternative to the GT750 drum
brake that will fit the 1972 front end? I'm wondering if the same vintage
GT550 or GT380 drum brake wheel and axel will fit the GT750 front end, or if
there are any other manufactures' wheels that will fit.

Failing this, would a slightly later model Suzuki disk brake wheel and lower
legs fit the 1972 triple trees and forks? In other words, would, let's say,
a 1974 GT550 wheel and forks work with the GT750 triple trees, or are the
forks a different diameter and the spacing different? The lower legs I have
now don't have the mount points for a disk brake, so I would either have to
replace the lower legs (or at least one of them), or the entire forks. This
then gets me into the question of whether the distance between the forks are
the same for the '72 GT750 triple trees and a later model disk brake setup.
If the drum setup is wider then I may be able to get away with a spacer. It
also prompts the question, are the diameter of the forks the same for
different years of Suzuki's in the early 70's? Is teh '72 GT750 front forks
the same diameter as, say, the '74 GT550 with disk brakes?

Lot's of questions, so I'm hoping there's a vintage Suzuki guy floating
around in here that can help.

Thanks in advance,

Tud

 

Suzuki was very slow to change anything in the 1970's and early
1980's.

Axles were the same diameter so they could use the same bearings and
oil seals.

I know for a fact that a 1974 GT750 front hub bolts up to the disks of
my 1982 GS1100. The axle is the same diameter too.

http://www.powersportspro.com/pages/parts/viewbybrand/parts.aspx

1972 GT750 upper triple clamp SKU: 51311-31000-019
BRACKET, FORK UPPER

1972 lower triple clamp SKU: 51410-31001
BRACKET, FORK LOWER

1974 upper triple clamp SKU: 51311-31700-019
STEERING STEM HEAD L,M,A; TO 51311-31701-019 L,M,A; TO 51311-31701-019

1974 lower triple clamp SKU: 51410-31700
STEERING STEM L,M,A; TO 51410-15210 L,M,A; TO 51410-15210

If you look at the steel fork stanchion tubes, you might find that the
1972 and 1974 forks have the same stanchion tubes, so the outer
aluminum sliders of a 1974 probably bolt right onto 1972 damper rods.

 

.. wrote...

Fantastic site, this will help a great deal in narrowing down (or
broadening) my options.

Sweet, looks like I can go with a disk brake.

Thanks a bunch.

The old extended Triumph front end:
http://tinyurl.com/58sa9u
The GT750 front end:
http://tinyurl.com/66fkxb

Tud

 

Tinker wrote...

Yeah, the last one I watched on E-Bay went for $566. Yikes!!

Thanks a bunch for the info, I think I have enough to go on now.

Tud

 

I hopet the 1972 and 1974 Water Buffalos having the exact same part
number triple clamp should dispel any doubt about the diameter of the
fork tubes and their spacing.

The difference in dash numbers on the lower triple clamp is probably
due to the slight difference in casting to accomodate the brake hose
junction fitting...

As Suzuki proceeded to accomodate customer demand for radical colors
and styling, many perfectly interchangeable basic part numbers gained
a plethora
of dash numbers

 

.. wrote...

Possibly, assuming that the diameter and spacing is determined by the 51311
number and not the 31000 versus 31700 number.

So the main part number is the 51311 and the numbers after that aren't as
critical, is that correct?

I'm thinking I may be wrong in that assumption. I typed in 51311 into that
web page and got back everything from a 2008 GSX1300BKA to a 1968 50M12.
The 51311-31000 narrows it down to just one year, the 1972 GT750 upper
triple tree that I have. When I get home I'll see if I can confirm this
number on the part itself. I'm hoping my starting point (the current triple
trees) isn't a one year item. The axel for the 1972 GT750 seems to fit a
whack of bikes, so I'm assuming that the width is at least the same as other
bikes.

I'm going through the page you pointed me to and am building up a list of
parts that should be interchangeable. Obviously I'm not going for an
accurate restoration, just trying to find something that'll work to get the
bike on the road.

 

I wrote...

I'm wrong, I double checked and the axel is a one year part number as well.

54711-31000

The axel for the 1973 GT750 fits a bunch of bikes, from a 1973 GT250 to a
1985 GS300, and many in between.

54711-33002

I'm beginning to think, based on the the triple trees and axel part numbers,
that I got a one year only front end (maybe not the forks, but the rest),
which means I may have to look into a different set of triple trees.

Tud

 

.. wrote...

I didn't get a chance to get to the bike last night, but I'm looking at some
pictures, and then looking at that website, and I'm beginning to think I
don't have a 1972 Suzuki GT750 front end. It's definitely a Suzuki front
end, and the lower legs aren't set up for a disk brake, so it'd be early
70's, but if I look at the top triple tree in the parts diagram on the page
you posted, the lower handle bar mounts are a part of the casting for the
upper triple tree. In this picture I took a few weeks ago I can see that my
triple trees have a bolt on lower handle bar mount.

http://tinyurl.com/5r3ywm

Now I REALLY need to take a look and see if I can find a part number on the
triple trees.

Tud

 

Your forks may be from a 1972 GT550.�

 

.. wrote...

I think you may be right, in which case it opens up a few more options.
I'll post back when I locate the part number on the triple trees.

Tud

 

Tud wrote...

Then again... no part numbers that I can find on the triple trees or forks.

 

The forks are on a 1972 Triumph frame, not a Water Buffalo.

 

.. wrote...
From looking at the page of Suzuki parts and looking specifically at the
image of the upper triple trees, I believe you're right, it's from a GT550,
not a GT750 as I originally believed. Knowing this, I can now make a list
of front wheels, axles, and lower legs that I can use with the current
triple trees and forks.

Which will hopefully be fairly light, at least until I get on it.

Just for interest sake, this is what I started with for $300 a few years
ago:
http://tinyurl.com/2pullp
http://tinyurl.com/5dyp6

The front end was extended and it pretty poor condition. This is where I'm
at now:
http://tinyurl.com/55vt8c

Tud

 

It looks like the handlebars were a yellow wooden (or plastic) broom
handle...

 

.. wrote...

They were actually made of a fairly thin metal, but could quite possibly
have been from a broom handle.

I actually tried to use them as leverage for something at one point, it
didn't work so well:

http://tinyurl.com/5ftknu

Tud

 

I made a straight drag bar for a 250cc Yamaha out of a piece of
aluminum tubing that was laying about, but it had a thicker wall so it
wouldn't buckle.