GT750 Exhaust. (3 into 1, 3 into 3, stock)

General discussion about Street two-stroke Suzuki motorcycles.

Moderators: oldjapanesebikes, H2RICK, diamondj, Suzsmokeyallan

User avatar
jaycee69
Around the block
Posts: 58
Joined: Sun Jan 15, 2012 11:33 am

GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by jaycee69 »

So i have been looking for a new exhaust for my GT750, But i am coming up with the same results.
People are asking the same Big question "Who is still making Exhaust for the GT750's?"
I decided to compile a list.
HiggSpeed 3 into 3 expansion chambers (Blackpool Lancashire, England)
http://www.higgspeed.com/SUZUKI-GT750" onclick="window.open(this.href);return false;

Jemco exhaust 3 into 3 expansion chambers (Houston Texas, U.S.A)
http://jemcoexhaust.com/downloads/Jemco ... atalog.pdf" onclick="window.open(this.href);return false;

Omars dirt track racing inc 3 into 1 Exhaust (Concord California, U.S.A)
http://www.omarsdtr.com/Ex750suz.html" onclick="window.open(this.href);return false;

Gibson exhausts 3 into 3 Expansion chambers (Romford Essex, United Kingdom)
http://gibsonexhausts.co.uk/page_11.php ... _catalogue" onclick="window.open(this.href);return false;

Jolly Moto 3 into 1 exhaust (Lombardy, Italy)
http://www.jollymoto.it/jolly-moto-2-st ... orical.php" onclick="window.open(this.href);return false;

Jim Lomas exhaust 3 into 3 exhaust (Czech Republic)
http://www.jl-mxshop.com/suzuki-gt750-27-c.asp" onclick="window.open(this.href);return false;

Delkevic Exhaust Stock exhaust reproduction (Staffordshire, United Kingdom)
http://www.delkevic.co.uk/?section=shop ... &order_by=" onclick="window.open(this.href);return false;

If you have anymore to add to this post please add them. or also please add pictures as some of them are hard to see on the websites small pictures.
73 GT550 K
77 GT750 B
88 Yamaha YSR50 (Street Legal)
91 Yamaha YSR80 (Street Legal)
Craig380
Expert racer
Posts: 1250
Joined: Mon Dec 01, 2008 2:52 am
Location: Manchester, UK

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by Craig380 »

Good call!

John Campbell in the UK used to make 'Campbell Geometric' chambers, which were very angular and trick-looking, and pretty rare too. He's still in business but only lists 4-stroke exhausts and 'custom one-offs'.

http://www.campbellcustom.co.uk/

Here's a set on a nice UK cafe Suzi: http://classic-motorbikes.net/specials/ ... 50/page/2/

Everyone has their favourites, I personally liked the look of Bassanis on the Suzis, that long, slim look does it for me :)
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
Vintageman
Expert racer
Posts: 1483
Joined: Tue May 18, 2010 5:38 pm
Country: USA
Suzuki 2-Strokes: Suz, Yam, Honda, Kaw.
Location: New Hampshire

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by Vintageman »

Jemco makes for Omar

Jemco will make the 3 into 1 for you direct.

They will tell you it is no good versus 3 into 3.

Call em
Current Bikes
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
User avatar
tz375
Moto GP
Posts: 6204
Joined: Mon Nov 03, 2008 10:47 am
Location: Illinois

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by tz375 »

They will tell you it is no good versus 3 into 3.
I'm not sure that Jon E would actually say that. He may tell you that the 3 into 3 makes more power though.

3 into 1 sounds better than stock pipes or 3:3 Jemco pipes in my opinion and they are very light. If you want more power than stock you need 3 pipes.
miked914
Around the block
Posts: 84
Joined: Thu Jan 03, 2013 4:46 pm
Country: United States
Suzuki 2-Strokes: GT380

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by miked914 »

I just received my 3:3 pipes for my GT380 from Jon at Jemco and they are a work of art! They are super light weight and the fitment is spot on.
User avatar
jaycee69
Around the block
Posts: 58
Joined: Sun Jan 15, 2012 11:33 am

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by jaycee69 »

Any body have any pictures of their exhaust to post?
73 GT550 K
77 GT750 B
88 Yamaha YSR50 (Street Legal)
91 Yamaha YSR80 (Street Legal)
zk0ot
On the main road
Posts: 152
Joined: Mon Jul 16, 2012 11:19 am
Country: usa
Suzuki 2-Strokes: 1
Location: S.E. Wisconsin

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by zk0ot »

There's a whole thread with pictures.
User avatar
Coyote
Moto GP
Posts: 3404
Joined: Tue Oct 21, 2008 2:41 pm
Country: USA
Suzuki 2-Strokes: GT550x2, GT750, GS1000
Location: Tulsa, Oklahoma

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by Coyote »

Here's your Bassanis. Admitangly on a 550, But the 750s look very similar.

Image
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
User avatar
tz375
Moto GP
Posts: 6204
Joined: Mon Nov 03, 2008 10:47 am
Location: Illinois

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by tz375 »

Chris, I forget how good that bike looks. And it reminds me why my bike looks good - it reminds me of yours. :D
User avatar
jaycee69
Around the block
Posts: 58
Joined: Sun Jan 15, 2012 11:33 am

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by jaycee69 »

does anyone have apic of the omar 3 into 1? id like to know what the silencer end looks like. cant for the life of me find a pic of it
73 GT550 K
77 GT750 B
88 Yamaha YSR50 (Street Legal)
91 Yamaha YSR80 (Street Legal)
User avatar
RING_DING
To the on ramp
Posts: 447
Joined: Thu Apr 21, 2011 5:32 am
Country: USA
Suzuki 2-Strokes: 1974 GT750 B-4 (JDM), 1975 GT750M
Location: North Carolina

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by RING_DING »

There's some pics of it on the Omar's website:
http://www.omarsdtr.com/cafe.html" onclick="window.open(this.href);return false;
1973 Suzuki GT750K with Sidecar - Bonneville 2020
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: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by jabcb »

Omar's GT750 was sold in 2011.
Here is a better pic of it:
viewtopic.php?f=2&t=4609&p=106607&hilit ... ar#p106607

Other pics are on a variety of sites. Here are a few more:
http://bringatrailer.com/2011/01/22/oma ... t750-cafe/
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
User avatar
tz375
Moto GP
Posts: 6204
Joined: Mon Nov 03, 2008 10:47 am
Location: Illinois

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by tz375 »

There have been quite a few exhaust threads including viewtopic.php?f=5&t=5986&start=165" onclick="window.open(this.href);return false; which has pictures of the OMAR/Jemco 3 into 1.
Vintageman
Expert racer
Posts: 1483
Joined: Tue May 18, 2010 5:38 pm
Country: USA
Suzuki 2-Strokes: Suz, Yam, Honda, Kaw.
Location: New Hampshire

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by Vintageman »

Tz375 (et al)

Both Dan and John told me poor perfromance. Call em yourself if you want to buy one or know more about their experience/opinion

I have no reason to lie ( may be paraphrasing, for I did not tape record them).

I really wanted a 3 into 1 to go along with my 3 into 3 for GT550, They knew that was my goal for I said so clearly I already had a 3 into 3.

They both talked me out of it even though i wnated to buy it

They sent me a pic after first call and looks OK to me. It has a single chamber section why I asked. Like a triple or twin snowmobile the single chamber when designed correctly still better than no chamber at all but less performance boost han seprate, but still should be better than stock/I was not interested if no chamber

I also think 3 into 1 sound awesome, why I wanted a 3 into 1 to go along with 3 into 3

After receiving pic I Followed up with Dan and he said too restrictive where it combined into, Dan just did not like this thing Jon originally said it gives poor performance and buy 3 into 3. I already have 3 into 3. So no sale

One or both said they make them for Omar.

They did not say if it was worse than stock for I did not ask

I have also talked to Omar (did that first) and he said no top end gain more torque and mainly much lighter that stock

All

None of these pipes even look similar in design. Would have to see dyno to know which does what performance gain if any.

Jemcos 3 into 3 look like they provide a lot of volume and more tapers

Cheers
Current Bikes
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
User avatar
tz375
Moto GP
Posts: 6204
Joined: Mon Nov 03, 2008 10:47 am
Location: Illinois

Re: GT750 Exhaust. (3 into 1, 3 into 3, stock)

Post by tz375 »

I'm just giving Jemco the benefit of the doubt in the words they actually used. It could be that the pipe was manufactured by them by designed by someone else and they are not wild about it. Or maybe they are saying that 3 into 3 pipes are better at higher revs. I wasn't on the call, so I'm just leaving them some wriggle room.

There has been an ongoing discussion on a couple of the Yamaha twins boards about a 2 into 1 pipe on an RZ that the pundits said was a complete flop. Turns out it made more torque and HP than either a mild pipe or high performance pipe up to 8000 where it peaked and at 8000 it appears to have made more power than a stock motor, so it's not all bad.

2 into 1 or 3 into 1 pipes are not intrinsically good or bad, but the pulses do interfere at higher revs which is why they tend to be designed to wok well at lower speeds and when they go off the pipe, they drop pretty fast. They can be designed to resonate at higher speeds to try to stretch the powerband but ultimately they can't get out of their own way.

There is an issue over collector design that is hard to resolve in a 3 into 1. In theory a merge collector needs to have an outlet which is around 50% larger than the intake pipes to allow for orderly gas flow but tah still has a large step in it as far as pulse generation is concerned.

It appears that in a 4 stroke system, gas flow is more important than wave propagation and in a two stroke it's the other way around. I haven't seen anything published on collector design but sleds use that approach on triples and twins very successfully, so it can't be an insurmountable problem.

The next issue is that the stuffing wave is split into 3 paths and although 2 are closed much of the time, wave energy is dissipated and that means less gas stuffed back in as the port closes. The end result is a sharp power drop after peak and if it's well designed great torque below that peak.

Ultimately physics wins every time. :)
Post Reply