Canada restrictive exhaust.

[DaveR]

Hey Dave, can you get a picture way down in there? Look at Petrol's first picture, it shows the tube is capped on the lower end, appx. 12" down in there. The exhaust gasses come thru the small holes in the wall of the tube. I'm betting yours is the same way. I think all the non "L" GS1000 chain drive (standard, "E", & "S") exhaust were the same till the 1980 "S" model, it was different, shorter & flat on the rear end, like the "L" models.

Can't get a good pic but what I see looking with a flashlight is in both mufflers the tube is separated, one 4'' down the other 8''. The edges of the separation look sharp not corroded which suggests they were punched out and not rotted. The separated pieces are rattling around inside the muffler.

[petrolhead]

i will try to get the mufflers out and grind the ´endcap´ off
Hopefully they are only welded at the end of the exhaust otherwise it might be difficult.

[steve murdoch]

In North America at least the stock exhaust systems for the GS1000 are extremely difficult to find and very pricey when you do find one.
Before you start dissecting yours i would consider looking into an aftermarket system.

[petrolhead]

It´s the same here, petrol tanks and exhaust systems...
But i want the original 4 in 2 exhaust and it should not block the gasses.
I´ll try to respect the system and force the mufflers out without damaging the exhaust.

[rphillips]

I really think your stock exhaust is exactly like it came from the factory. No way anyone could have got down in there & capped the end of the tube. That & there would be no reason for doing it. Don't know what you are comparing your low on power to, but I'd bet the exhaust has nothing to do with it. It's yours, but modifying a stock set of GS1000 exhaust may not be the best idea. Also after you open up the orig. exhaust it will never "sound orig." again. On my first GS1100E the orig. owner had drilled out the 6 little blocked off detents in the back of the exhaust, it sounded like crap. I'd think this over real good before doing anything drastic. Hard to believe nobody can shine a light down it theirs & make a picture to show what theirs look like. Good luck, we're on your side.

[petrolhead]

i am comparing it with my old Suzuki GS1000E same year 1978.
And I have owned a lot of old Japanese bikes; so I am sure it lacks power.
I already thoroughly cleaned the carbs (unfortunatly i forget to write down the needle specs)
But this is a unmolested bike with low mileage and even the original toolset with air-gage was present.
It is like the engine won´t breath, you can feel there´s something going on.
No good power band when you rev it.
And I have never seen a muffler with one end closed, this seems not logical to me.
On the carb end you have 4 x 26 mm. inlets and on the other end the gasses have to go through al lot of tiny holes in the side of a tube.
I am not well known with mufflers but this seems very wrong for a sportsbike.
So i am still curious, do other gs1000e bikes have the same ´on one side closed´ muffler ???

[Gorminrider]

^Yes,as Rphillups and the rest are nicely trying to say is:
The "blockage" you see in yours is correct-because, the exhaust is NOT SUPPOSED TO BLOW THROUGH DIRECT. It is diverted to exit through the screen you see there. Another name for the "blockage" is BAFFLE.
I'd be more worried about the other one if you can see through it.

[petrolhead]

Thank you all for helping out !
I will check the ignition system as this is my last possible cause of trouble. (and for me the hardest cause i don´t know much about electronic ignitions)
It is good to know i don´t have to disseamble my exhausts !
Again thanks for all the help, keep them on the road ;-)

[rphillips]

Just a thought, if the ign. advancer isn't advancing it will be low on power. I had one get grunged up & not advancing on an "80" GS1100, yrs. ago. Got it loosened up & lubricated it good & all was well. Hopefully as simple as that.

[Big T]

Well, the 78 came with points ignition.
Is yours converted to electronic?

[petrolhead]

Yes, it´s converted.
I guess it is the only non original part.
i will check if it is electronically advanced or still has the mechanical advancer behind the plate.

[petrolhead]

I want to thank you all for talking me out of my obsession that my exhaust was wrong.
Because i had cleaned my carbs and because i have an electronic ignition i thougth it was the only possible cause of the lack of power.
After marking the timing and disassembling the ignition i found out that the mechanical advancer was stuck
It seems i have to learn (again) that you can´t take things for granted.
To know something is to check it.
Thanks for youré help and patience, keep them on the road !!!

[Big T]

Thanks for reporting back

[Steve]

Just now saw this thread and through I would offer my observation on the muffler baffle.

Some of the OEM mufflers had a system of disks with multiple small tubes between them. The exhaust gasses would be necked down to go through the first tube and be directed to a chamber past the second disk. A second tube would re-direct the gasses back to the chamber between the first and second disks. A third tube would then take the gasses to a chamber past a possible third disk, where it would then go through the perforations that you see and finally out the end. In spite of all the re-directions, they were remarkably free-flowing, along with being very quiet.

A MAC 4-into-1 system with a "street" baffle has two separate pipes that overlap between two disks. The exhaust only has to re-direct one time, so it's just a little louder, but still not bad. Their "performance" baffle has a single perforated tube that goes directly between the two disks. The diameter of the tube determines the noise level. Wrapping the chamber around the perforated tube kills some of the echoes, shaping the sound a bit.

I have a 4-into-1 pipe on my 850 of unknown origin. It has a single perforated tube between two disks, but there is a solid disk in the middle of that tube. That forces all the exhaust through the perforations in the first half of the tube, into the outer chamber, then back through the perforations in the rear half of the tube. A different sound, but I like it.

Your perforated tube looks a lot like mine, so I don't think there is anything wrong with it. I don't know what's ahead of that picture, but rest assured, it works quite well.

.

[rphillips]

Amazing how aggravating things can be to diagnose, as opposed to how simple they can be to fix. Congrats.