'73 GT750 Exhaust Quandry

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Brealytren
Still in the Driveway
Posts: 2
Joined: Sat Apr 15, 2023 10:31 am
Country: United States
Suzuki 2-Strokes: 1973 GT750

'73 GT750 Exhaust Quandry

Post by Brealytren »

As I work to bring back my new to me '73 GT750, I no doubt am working through many of the same challenges each of you have worked through in the past. That said, the bike in question came to me with a '75 - '77 OEM exhaust. I immediately noticed that aftermarket rear exhaust mount brackets were installed, both of which were cobbled on with elongated bolt holes to accommodate the bike. In addition, I noticed that not only was the center stand removed, but whoever removed it, also cut the mounting tabs off the frame. As I've had BAD experiences of side stand failure with other bikes, my first mission was to get it replaced. I sourced an OEM stand, including the mounting tabs, and welded it on in the exact place the original was. After reinstalling the exhaust, I found all of the cutouts in the exhaust pipes to accommodate the side stand, center stand, etc, were all forward about an inch of where they should be. All that said, it appears the ''75-'77 model exhaust system is extended about an inch compared to the early exhaust with the black tips. MY QUESTIONS : What have others done to remedy this situation? Am I completely wrong in my assessment that an early exhaust would fit..... but is IMPOSSIBLE to find. Are there any other options? I understand Delkevic offers a new system yet their disclaimers lead me to believe that it will have the same fitment issues as mine. They also offer an expansion chamber option....but I will again lose the center stand. HELP!!!
'73 GT750K - Project
'71 Norton Commando 750
'71 BSA 650 Lightning
'71 Moto Guzzi Ambassador x 2
'79 Honda CB750K - Franken Bike
'83 Yamaha XJ660LK SECA Turbo
'75 Honda CB360T - Project
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Alan H
Moto GP
Posts: 3169
Joined: Thu Feb 16, 2012 11:50 am
Country: England
Suzuki 2-Strokes: 4 x GT550s - J, M, A, B.
Location: The Republic of South Yorkshire

Re: '73 GT750 Exhaust Quandry

Post by Alan H »

Have a read of this first and most of your questions should be answered.
https://www.oldjapanesebikes.com/
Start off with the 'Field guide to the GT750' then look at other parts as required.

Unfortunately in the world of classic bikes (and cars etc. etc. - you get the picture), it's fairly easy to change a less popular model for one that is more desirable - & expensive. There were frame, exhaust, engine changes between early & late models to catch the unwary, and it appears you have been caught.
Other sites that may be helpful are - https://www.pinkpossum.com/ , - https://www.suzukicycles.org/ , - https://www.ozebook.com/compendium/suzi ... engnos.htm , - & https://alpha-sports.com/suzuki_parts.htm where there are lots of exploded parts diagrams for all years of different Suzuki models. All links are worth saving on your computer.

It may well be that the exhaust may not be the correct one and you are trying to cobble together a lot of mismatched parts. Good luck with the work, it will help you (and us!) if you do a basic introduction and tell us where you are from and a bit about you past biking exploits - there may be people near you that can help with advice at close quarters.
Think of how stupid the average person is, then realise that half of them are more stupid than that.
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jabcb
Moto GP
Posts: 4241
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: '73 GT750 Exhaust Quandry

Post by jabcb »

After the first few model years, Suzuki redesigned the frame+exhaust on the GT380 & GT750 to improve cornering clearance.
So combining an early model frame & later model exhaust is a PITA.

Aftermarket expansion chambers can also have cornering clearance problems because they don’t have a cutout for the side stand.

Higgspeed has 3-into-3 & 3-into-1 expansion chambers for both the early & late model GT750s.
The easiest solution probably is a 3-into-1 Higgspeed. It’s compatible with the center stand & does not restrict side stand movement.
https://higgspeed.com/product/expansion ... i-gt750jk/

The exhaust mounts on the GT380/GT550/GT750 frames have rubber bushes that damped vibrations. If your modified frame eliminated those bushes, you may run into cracking problems with an aftermarket exhaust.

We may be able to provide more insight if you post pics of what you have.
We can’t post pics on this site. Post them to a photo sharing website & include links to them here. I use Flickr — it’s free & easy to use.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
Brealytren
Still in the Driveway
Posts: 2
Joined: Sat Apr 15, 2023 10:31 am
Country: United States
Suzuki 2-Strokes: 1973 GT750

Re: '73 GT750 Exhaust Quandry

Post by Brealytren »

All,
A quick update. I'd like to introduce myself and share more about my experiences and background restoring bikes and Porsches, yet I'm not sure if this thread is the venue. Many forums have a thread specifically for this purpose. Let me know where I should post a bit about me and I will be happy to do so.

That said, after much research, reading your posts, and self-reflection, I've concluded that early bikes (thru 1973) came with pipes fitted with black cone tips. Dimensionally, those pipes are shorter than the pipes with round chrome ends fitted on 1974 - 1977 models. For whatever reason, my bike came already fitted with the late model pipes, and due to the poor fitment around the center stand and rear mounts, the center stand was cut off, and homemade brackets were fashioned (they look factory-made) to accommodate misalignment of the mounting holes. This leaves me with three choices. Find a nice set of black cone-tipped pipes that will fit perfectly (nearly impossible), cut off the newly welded on center stand and side stand and relocate them to match up to the late model pipes as well as use the custom rear mounting brackets, or finally, throw in the towel and switch to expansion pipes and give up on my goal to have a center stand. Thoughts????
'73 GT750K - Project
'71 Norton Commando 750
'71 BSA 650 Lightning
'71 Moto Guzzi Ambassador x 2
'79 Honda CB750K - Franken Bike
'83 Yamaha XJ660LK SECA Turbo
'75 Honda CB360T - Project
User avatar
jabcb
Moto GP
Posts: 4241
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: '73 GT750 Exhaust Quandry

Post by jabcb »

Seeing pics of what you have might help in narrowing down your choices.

The Higgspeed 3-into-1 accommodates the stock center stand. Might be able to get it to work for you.
Their video:
https://youtu.be/BVKPjrg5mpo?si=UOpxSoMmnwv_EEnk
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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