Replaced the exhaust collector.

84 700.

When I bought the bike, the PO didn't bother to mention one of the header pipes was crushed halfway. I missed it by not looking behind the lower cowl. Live and learn.

It took over a month to find a good one on ebay. I guess that's not much of a wait.

The job was a major PITA (for me anyway). There was little room to get the clamps undone. I had to use a block of wood and a prybar to work the collector off the back headers while at the same time dropping the fronts down.

I bought new bushings for the rear and new copper crush washers for the heads. Using red silicone to stick the washers up into the heads to keep them from falling out was helpful. I tried to slip the rear bushings (graphite tubes) into the replacement collector and they wouldn't fit. A pipe expander from Harbor Freight took care of that. I put the bushings on the rear headers and then worked the collector/headers into place. A light touch and small movements was the way to go.

There are two mounting bolts, one on either side of the collector. Putting them back in was a challenge. The holes on the right side were hard to line up. The ones on the left were worse. I finally had to remove the right side bolt and then work on getting the left side in. I had to pull the collector down a bit and twist it with the prybar to get the bolt in. It was a miracle I didn't cross thread it.

Well all's good with the exhaust now, but when I fired it up for the first time, it wouldn't idle below 3000. A friend suggested I just drop the idle. Adjusting the idle has never seemed to be a good way to fix anything but I'll be damned, that was the trick.

I'm wondering if the restriction caused the PO to adjust the idle screw and when the new pipes were installed, it had to be put back? I don't really know, just a guess....

 

That sounds like fun, so be sure to never crush the collector huh! Was your original collector crushed or just the pipe?

Can you do me a favor and take a look at your old collector and see which cylinders go to which side? I have asked and got two different answers. I'm wondering if the front cylinders stay on their side but the back two crossover inside the collector? Or do all 4 exhaust on their side? Left two cylinders = left pipe, right two cylinders = right pipe?

 

Just the pipe was crushed.

Take a look at the pic from tinkerinWstuff. Not exactly sure what is going on here.

http://vfrworld.com/forums/showthread.php/40501-Gutting-the-exhaust-collector


What confuses me is the front of the collector is sloted for the front headers. If I remember right, the front headers on mine where pressed in and maybe spot welded.

 

Oh wow! That pic explains it all....thanks! I searched for a pic like that and could never find it.

So it's neither of the two options I listed. All four go to each side because all 4 open end in the collector. The front two open end in the collector with that 45 deg cut. Then the back two go in and each make a 90 and a 180 then open end. Those bends are to in effect make the rear short pipes the same length as the longer front two when they exit into the collector. See the two holes drilled into the bend, they probably had to relieve the pressure some in those 180's because they are so restrictive.

Very cool to know what's going on in there. Looks like a wonderful place for mice to make a home on a bike that sits for too long.