4:2:1 exhaust for 76-79 GS750???

[Chuck78]

have any of you seen a 4 into 2 into 1 exhaust header available for a first generation GS750? So far I've only seen them available for the 1980 and up GS750's

Same deal with the X-pipe setup that the old Maxi-Bore carb guy makes, 80+ GS750... I think that would probably be not a deep enough sound for my likings due to the short length, however, but it would be quite loud!







my 4 into 1 Mac header right now looks like it is off of a different model or a Kawasaki, and hangs a bit lower than I would care. I wonder if a later 750 model or GS 1000 would be the same deal, longer stroke/cylinders on the bigger bikes at least.

I really should probably be looking out for a Vance and Hines Road racing version with the up swept muffler. Chrome would be nice but the Mac looks great in my eyes, just thinner metal that I always have to touch up the black paint on however.

[kimjay]

Awesome, thanks for that link. I've been looking for that exhaust for days, it will look great on my GS550 brat/cafe style bike.

[posplayr]

Just a mention, I have enjoyed my 4:2:1 FrankenYoshi as it improved mid range which for the street is good. The jetting is more like stock although a bigger main is still required depending upon motor and pod installs.

In fact I've considered going back to a stock needle to see if I can get a better tune on mine. The DJ needle is designed for the 4:1 which has a definite leaning in mid range. So my best tuning ends up with a trade between too lean in mid range and to rich on both other ends. My theory is the stock needle will be richer in mid range and I can get smoother transitions from low to high RPM with the stock needle.

Since I have moved to AZ, I'm running richer now with the 2K altitude here in Tuscon. So an adjustment is required in any event.

http://www.thegsresources.com/_forum/showpost.php?p=1267319&postcount=1

[kimjay]

After reading stuff on this guy not so sure about the exhaust. Someone on here last year had one made and had measurements and all that but for the life of me i can't find it.

[Chuck78]

Those Campbell X pipes are VERY pricey, like $550-600, but very sharp. fabricating one with the factory downpipes seems do-able maybe with a little help from a muffler shop or using a commercial/industrial conduit bender. Then you may have to make a slip joint fit if you want the rear half chrome plated. Sounds like it could be an interesting project for someone who had free time.

The 4:2:1 I was turned onto because apparently if you have a 4:1, you get a little interference at idle and low throttle that can give you a little but of that popping and hissing out of the air filters, as well as what posplayer said in terms of a stronger midrange.

What do you mean by "FrankenYoshi?" Is that for a GS750, or is that for your 1100E? I'm just wondering if anyone has ever even made a 4:2:1 "Tri-Y" for the first gen GS750's.

[posplayr]

What do you mean by "FrankenYoshi?" Is that for a GS750, or is that for your 1100E? I'm just wondering if anyone has ever even made a 4:2:1 "Tri-Y" for the first gen GS750's.

I have a stainless 2nd Gen GSXR 1100 4:2:1 Yoshi, with custom stainless mid pipe fitted to a Honda 550 Yoshi vintage can with V&H spigots. It is on the GS1100ED in my signature.

By the time I got it all done it was over $600 for a used concoction. So in my mind, a $550-$600 brand new stainless pipe that fits is not bad if you can find one.

[kimjay]

That's true, not overly priced if it's quality, but i've read that you have to weld it yourself and remove it for oil changes. Looks beautifull in the picture though.

[kimjay]

Would anyone know if the later model 82-85 gs550's or katana's or have the same cylinder spacing for exhaust i really don't want a mac on my bike and have found a vance and hines from 85 for decent price.

[tkent02]

Cylinder spacing for the 550 and 650 is different than that of the 750 and up.

[kimjay]

Thanks, but i'm wondering just about the 550's. There is a gs550 katana in 85 i believe.

[Chuck78]

Found a $30 89 Kaw ZX7 4-2-1 at the VJMC junkyard today. It's tempting me... I'm gonna have to look for that thread of Posplayer's where he modified his Yoshi exhaust to fit. I do remember looking at a photo where he had photoshopped arrows and text saying "bend here--->" in two places to make his fit.


compared to a GS Vance and Hines 12009:



I think I remembered reading that it was rumored that ZX11 or some other similar exhausts had been modified to fit a GS or two, from one of these franken-exhaust retrofit threads.
The Kaw cylinder banks don't lean nearly as far forward, so the exhaust comes at far less of an angle sweeping back. If I could heat it up and tweak the two bends by the cylinder and the bend at the bottom and lessen the angles, then I'd have my 4-2-1. the cylinder spacing was a little narrower, but I think I could make that work. When you bend it side to side, you have to really crank on it to keep the pipe from twisting so that stays flat with the cylinder head.

I would most likely have to paint it black or wrap the exhaust after the heating and bending, but it has some rust specs all over it anyways. No biggie. Maybe a GSXR 4-2-1 would be a better bet?

My MAC 4-1 I believe has 1-3/8 pipes, and this one measures around 1-5/16. I wonder how the exhaust gaskets would work out? Buy some for a GS650? I think not only the 4-2-1 but also the slight decrease in pipe diameter would boost midrange torque a fair bit. Big question is in bending the tubing... posplayer, how do-able? My current beat up MAC fit like crap, and I heated it red hot with a straight acetylene brazing torch (no oxy) and lifted the bike with a floor jack by the muffler end of the 4-1 and tweaked it (I think it is for an 80+ GS750, fit was too tall), but I think I needed a second person and torch to do that justice keeping 4 pipes red hot simultaneously. I got it somewhat where I wanted it though.

[Chuck78]

This also has the pipes paired as stock duals at the 4-2, 1&2 together, 3&4 together. The MAC 4-2-1 Tri-Y for the 80 GS750 has 1&4 paired and 2-3 paired. Is this better???



Would a Gixxer 4-2-1 be far easier to adapt (less bending necessary)??? I have enough projects, but this would be nice to have on my bike if I could make it happen. The side exit I figured I would chop up and weld at whatever angles I needed to get the muffler directly under the passenger footpegs, but the angles coming off the engine are where the most bending is needed.

[posplayr]

Is that a chrome or stainless exhaust? For $30 I woudl grab it and see if there is any way to make it work. Buy two they are cheap and I'm sure someone would buy it from you after making mods, especially if that is stainless. Of course start with one.

There are far and few between GSXR 4:2:1's unless you go to water-cooled bikes. After a couple of ebay years looking I ended up with two; one on my bike and the other since sold. There also stock TI exhausts that can probably be modified. There are threads on that at gixxer.com in the oil cooled forum. I think with minor modification a TI pipe was fitted to a 1st Gen GSXR . It may have been a 750 through which has the shorted stroke than the 100, which still might be a better fit on a GS 750 than a GS1100.


BTW I did not have to bend my pipe after all, but I did have to put on exhaust spigots to clear the frame cross member just under the ports. It hangs a little low, but not so much that I did not gain ground clearance due to the 4:2:1 which is another main benefit if you plan on going to 17" wheels.

[Chuck78]

The 4-2-1 is very tempting, but i think i just need a bolt on and not another project. The 4-2-1 might work quite well on my buddy's kz650csr, so i may push that off on him, but it'd sure look sweet, and I like how it routes to the muffler with a nice upswept elevation.. I'm not looking forward to trying to bend the top forward 2" to get the correct angle, however. I happened upon a $200 vance&hines 12009 pipe, might go with that instead. I really would like to fit one of these though.

Has anyone had any luck or have any tips on bending exhaust to reshapeor relocate portions of them?

[posplayr]

The 4-2-1 is very tempting, but i think i just need a bolt on and not another project. The 4-2-1 might work quite well on my buddy's kz650csr, so i may push that off on him, but it'd sure look sweet, and I like how it routes to the muffler with a nice upswept elevation.. I'm not looking forward to trying to bend the top forward 2" to get the correct angle, however. I happened upon a $200 vance&hines 12009 pipe, might go with that instead. I really would like to fit one of these though.

Has anyone had any luck or have any tips on bending exhaust to reshapeor relocate portions of them?

Harbor freight have inexpensive pipe benders and the best way to keep the pipe from crimping is to pack it with sand. It will be much easier to bend if you can get the metal soft with heat. If you don't access to a torch, then it would probably be hard to do.