Question re: Installing Exhaust System

I should be getting a new Mac 4 in 1 Megaphone set tomorrow. I pulled off the old, dented, rusty Kerkers today. I noticed the Kerker had a two piece exhaust pipe gasket (eight total) where the pipe meets the exhaust ports on the engine.

Is this something I would reuse, or do these pipes generally come with their own unique gaskets?

 

Here's a pic from Dennis Kirk of the Macs. I could only find 4 into 2's, but these should attach the same way. From the image, it looks like it doesn't use a gasket.

 

I'd say just about everything you need will be in the box.
You might need some Exhaust Flange Donuts. Although I know unless they are burned-through they hang-in-there and do just fine being reused.

You can treat the Donuts with a nice new glaze of Permatex Hi-Tack Spray-A-Gasket and seal 'em up tight.

Shoot the Spray-A-Gasket into a Tune Can and "Dip" the Donuts.
Let dry.
Dip again.
They will be very sticky ... but, that's what you want.

 

that sounds like the PO installed a set of exhaust gaskets without removing the old ones. The old gaskets can be so covered in soot and oxidation that you can't see the seam between it and the port making it look like no gasket is present. These gaskets can usualy be reused so pick the best of the eight and install those four.

 

Cleaned the soot, no gaskets. Here is a pic of the ones I did pull out:




I'll see what is included in the Mac box. I suspect they have their own gaskets. Hard to tell from the product image - that could even be a generic image. I had thought that since it looks like the end of the pipe is flanged, that maybe it wouldn't need a gasket.

 

thats a super sweet looking set of pipes...

nice...

d

 

So that's why there are eight pieces! Split gaskets....haven't seen those in a while. The original Yamaha gaskets are ring gaskets or donuts as we call them and are a complete circle. Split rings are usually used to make a slightly smaller pipe fit into the port and seal on the sides instead of the ends. They may not fit the new header pipes. If not then you will have to use the original donut type.

 

Looks like somebody did a "fitting" of larger gaskets to fit the exhaust port.

Those donuts are pretty cheap. Maybe you should order a new set and tell them what size the exhaust port is so you are sure to get the right ones and use them whole.

 

I don't have the originals. Hopefully Mac includes them. I don't want to have to reinstall that old Kerker set while waiting for gaskets.

Are gaskets always required? The Mac ends seem flanged, unlike the stock or Kerker versions.

 

Yes. You need Exhaust Flange Gaskets.

There'e no way the System could be gas tight without them.

 

Those half round parts in the photo are not gaskets, they are spacers that go in over top of the exhaust pipe flange so the clamp will hold the pipe in securely. If the clamps are welded to the pipes like the new ones in the photo then you don't need the half round parts. The donut gaskets should still be installed into the exhaust port before the pipes go in though.

 

Could someone describe those gaskets please? They may be in there, underneath the soot. But I'd rather not damage them by poking around, especially if they are small and dainty.

 

Little round asbestos rings with a thin metal cover that fit snugly in the opening. I've heard that you can take the exhaust gasket from a Chevy V8 and cut the rings out around the ports to use but never tried it.

 

When I put an "Instantly-turned-blue" Jardine 2 into 1 System on my XS650, I had to "Double the Donuts" to make it Gas tight.

Those Aftermarket Systems that do away with the Exhaust Header Collars are just a little bit loose fitting. You may wind-up having to pull the same stunt with that MAC System.

Is that MAC System "Oil Filter and Center Stand Friendly" ... or, are you going to need to drop the Headers to get a new Oil Filter in ... and, eliminate the Center Stand when you put it on???

 

The Macs didn't come with gaskets, so I had to order some. Seem fairly snug without them, though not gas tight. <cough><cough>

Rick - they are split near the bottom, so I can easily change oil without dropping the headers. Yay!

I'm not sure what you mean by eliminate the center stand. The system did come with an L bracket to be used as a center stand stop. However, the shape of the megaphone muffler prevents it's use. It's all good, though, as that same design tucks the muffler up and out enough so the center stand doesn't hit on anything when it is retracted.

 

That's good!

Some of the aftermarket exhaust systems require the Center Stand to be removed.
To me ... that would be a serious drawback.
I really rely on the stand. I can't imagine what a hassle it would be to be without one.

 

Look at this old posting, the last enty is a picture of a "cleaned" up old gasket.
http://www.xjbikes.com/Forums/viewtopic ... asket.html

 

Yipe, thats a "clean" one? I hate to see a dirty one.

Ok, those are not in there, so it's good I ordered a set. The pipes fit in there snugly. I gave a test ride a bit, and there is some exhaust escaping from the ports. So I won't be riding much until I get the gaskets.

The pipes sound great, btw. Even with the baffle in. That 650 can ROAR, can't it? I bet with no baffles, it may be even louder than the Kerker.

 

If you run without the baffle ... do some frequent "Plug Reads" ... you might find that you are running a little Lean because of No Back-pressure.

 

Well I wish I coud have posted before you ordered the gaskets. I suspect you have a set in the cylinder head. The old header could not have sealed without them. They are quite hard to distinguish from the port after time has left it's exhaust deposits on them. When you get the new gaskets in just try one in and see how much depth is left for the header. This is how I found out my old one were still there. Not enough room to seat the header deep enough with a new gasket in place. I used a dental pick to pull my old ones out. Not an easy job either.

 

And when you get them all set up, post an after pic so we can see the look. I have a bad imagination for seeing what a finished look is, even if I know how all the parts connect. If you can get a short vid of them, I'd love to hear their sound too.

Jon

 

They were only about $13 for a set. Not a big loss. I'm thinking (not always a good thing ) that because the Kerker pipes were thinner, which necessitated the split spacers, then maybe a PO pulled out the old gaskets.

I'm not sure how the gaskets seat with the pipes in there. If they seal at the point where metal meets engine block, or if the seal around the entire pipe end.

I've also notice a more pronounced ticking noise in rhythm with the rpm, especially when the engine is cold. I had attributed that to an inadequate seal. Or maybe it's always been there, except now I can hear it better.

I'll post pics and maybe a video. It's definitely quieter now, especially in lower rpms. If stock was 1, and open pipes is 9... I would say the Kerker (with baffle) was about 8, the Macs are a 4. However, crank it up, and the Macs rise to about a 6 or 7.

 

Also - regarding those baffles - I see the set screw, and pulled it out. But those baffles were too hard to pull out. I didn't want to deform them in the process. Has anyone had success doing this?