Need advice about new exhaust for 79 GS750L

[mk]

The old Kerker 4 into 1 exhaust on my bike has finally convinced me to get a new one. It has a nasty habit of scraping the ground in right turns. Today it scraped hard in a fairly easy turn riding 2 up, which is the last straw - there are safer ways to get an adrenalin rush.

I've found 4 into 1 pipes from V&H and Mac, and even a NOS Jardine. Also, there's a NOS 4 into 2 available from MAC. My concern is first to get a new (or used) exhaust that doesn't drag the ground - which is the only reason I'm considering 4 into 2's. After that, it would be nice not to have to rejet and, of course, keep the center stand, service points and rear pegs on the bike and accessible.

An interesting side note is that the bike is a 79 GS750L model, but the frame is listed on its plate as a 79 750E .

Any words of wisdom or warning that can help the transition will be greatly appreciated .

[Keith Winter]

I have the Mac 4 into 1 on my 1000. The oil filter is easy to get at, the center stand works fine, and except for very high speed bumps, the ground clearence is all you need. I've never been able to drag them yet.

[jonr]

I have a Mac 4-1 on my 78 GS750E. I've never rubbed the exhaust on anything except for when I had a high-center scuff getting out of a trailer with a short ramp.

I've even leaned so hard as to have my back tire slide out a bit and it never touched the pipes. Had a few nasty bumps where I though my spine cracked and the pipes never hit. As mentioned previously, centerstand and filter access are good.

-jon

[mk]

Thanks for the info Jon & Keith! Sounds like the Mac 4-1 exhaust will get rid of my "scrapes". The only qualms I have about the Mac is all the bad mouthing I've read in other posts about the quality (rusts out easily, etc.). If you've had Mac awhile and find the quality good, let me know.

Michael

[jonr]

Michael,

I don't know how long my Mac exhaust has been on my bike, but it has been at least eight years (since I've owned the bike). The baffle was missing when I bought it, but the chrome was in decent shape and it still is. The muffler area is in extremely good shape, whereas my pipes are starting to look a bit shabby, especially since I have never polished them with chrome polish.

I would recommend that you could probably count on it for at least 10 years if not more if you keep them cleaned up as you go.

Send a PM to Greg Wasserott. He's got a 78 or 79 I believe and he just put a new exhaust on it not too long ago. We were comparing notes at the Nashville, IN rally, but I can't remember what brand it was.

Here's his profile info:

http://www.thegsresources.com/_forum/profile.php?mode=viewprofile&u=2058

-Jon

[mk]

Jon,

Thanks for the further info and referral to Greg. The Kerker on my bike was missing a baffle when I got it, but it kept scaring little kids and every animal for miles so I got a new baffle for it.

How is the sound on your Mac - assuming you got a replacement baffle?

Michael

[jonr]

Michael,

Intermediately noisey. I ran with out the baffle for about a year and decided that I had had enough. Basically, I just fabricated a cap that fits in where the old mounting holes for the baffle were. The cap matches the inside diameter and I have a 1.5" hole cut out of it. It cut the noise down by about 50% (it seems like) and I did not take too much of a performance loss. I've been running that cap for six or seven years now. I've always planned on making a simple baffle to weld on to the cap, but never got around to it. Despite the volume decrease, the bike still sounds like it's from the race track. Pretty mean!

The mac baffles are peculiar. Instead of having a perforated cylinder (sometimes wrapped in fiberglass) they use a two tube method that forces the exhaust to make two 180 degree turns before it exits the muffler. Since I've never owned the proper baffle, I could not tell you what it sounds like. Here is an image for you to compare:

http://www.oldbikebarn.com/motorcycle_parts.php?bike=&subcategory=Baffles&DisplayPerPage=10&Start=0

-Jon