collector question

[uncledj]

Been round and round with this exhaust problem. The good news is that now that I've had it apart 3 times, and have lubed the pipes and collector with a hi temp never seize, it all comes apart and goes together quickly.

I pulled it all apart to get the closest inspection of the collector. I was sure there would be some visible signs of failure, but there's not. Externally it looks great. No cracks, all metal seems solid, but put it back together paying special attention to all gaskets and connections, and she still has "the sound" .....you know...the "hotrod" sound.

I'm out of options. The baffles must be having an issue inside the collector.

My question is: If I cut a square as big as possible out of the bottom of the collector, will I be able to gain enough access to weld the naughty baffle (s) back in place?

I did a search and found only pics of the collector with baffles removed. I'd like to keep mine as quiet as possible, so would a competent welder such as myself have anything to work with once I open it up, or should I spend the big bucks and get a replacement...???

The ones I see on e-bay right now are going for $150 , which is OK, but the ones I'm seeing look to be in worse shape than the one I have.

I'm planning on pulling it back apart tomorrow, but I don't know what to expect when I open it up.

Anybody out there who's done this before?

Thanks:confused24:

[dingy]

There are not really baffles in the collector, its more like about 1/16" perforated metal. Lot of small holes very close together.

 

If you screw yours up I have a spare I will part with for less than the Ebay ones, and I will tell you truthfully what shape its in, which is good.

 

Gary

[uncledj]

Cool...Thanks...

Knowing there's a decent one out there takes some of the fear out of cutting apart the one I've got. I'll get into it tomorrow after work and see if I can identify the problem. The thing that gets me is that what I can see from looking in the inlet / outlet ports looks very healthy. I'd think that if it was rusted or blown apart I'd be able to see some evidence.

[dingy]

And your only about 45 minutes from me. You could come up and get it some evening.

 

592 Michigan Ave, Mansfield Oh.

 

Gary

[frankd]

This spring, my 89 started sounding a bit different....First off, I thought I had a gasket leaking. I took it apart and found that I had what looked a bad gasket, and also, I had a broken clamp on a rear cyclinder pipe. I fixed all of that and started it up....no change. I did have another collector though. I knew for certain that the screen was loose inside this one, because it rattled when you shook it (actually this was the original from the 89). I cut this one apart, removed the completely broken screen, had a friend weld up the collector for me, and installed it. Now it sounded a lot better. I need to say though, that it is a little louder than original. This was evident when I worked on the 83 and compared it to the 89. It is a subtle difference though.

 

I assumed that the first collector had the screen come loose on one side. I never cut it open, but it doesn't rattle and nothing else could go wrong with it.

 

Frank D.

[uncledj]

I couldn't do it.

I took the entire exhaust system off again. This time it only took about 20 minutes from start until the entire system was off. I could pretty much do it blindfolded at this point, and with never seize on everything, it slips right apart / together.

I had the collector in my hands, and looked carefully over every square inch of it. It had a minor crack (1/2") on the mounting bracket, which did not go down to the case of the collector itself. Nothing else externally, barely any rust.

I looked down the tubes with a small flashlight and can see the perforated screen, ...not rusted at all. I took a small inspection mirror, and was only able to get it through the outlet pipes into the collector, and could get a fair view of the inside.....tricky, but with the mirror and the flashlight I got a pretty good view. The screen looked great. I looked it over again and again looking for inconsistencies but found none.

It looked so good I couldn't make myself cut it apart. I put it all back together and tightened the bejesus out of the clamp bolts, and the sound is still there.

I'm gonna try changing the collector and see what happens.

 

 

 

 

 

[twigg]

The perforated screen doesn't generally rust. It breaks free from its welds, probably due to vibration over time.

 

I cut mine open because of a rattle, and it was perfect inside so I left it alone and it was welded closed again.

 

The front downpipes are double-walled. In my case the inner had separated from the outer pipe, and was vibrating when it was hot.

 

It took a pretty close examination to see where the pipe had sheared internally. I eventually diagnosed it when I realised that one downpipe was heating up much faster than the other, and all cylinders were firing.

 

Then I went looking for a crack ... $20 spent on eBay took care of it.

[uncledj]

Now THAT sounds interesting.....

Where did you check for the temperature difference, up near the head or down near the collector???

Is it repairable, or would it need replaced.

 

Also: What are the bolts in each exhaust pipe for? I figured they must be some sort of exhaust gas test port to isolate the cylinders when testing.

[twigg]

Now THAT sounds interesting.....

Where did you check for the temperature difference, up near the head or down near the collector???

Is it repairable, or would it need replaced.

 

Also: What are the bolts in each exhaust pipe for? I figured they must be some sort of exhaust gas test port to isolate the cylinders when testing.

 

The bolts are for a gas analyzer probe.

 

If the inner is broken it would not be repairable. Apart from the access difficulties, the carbon embedded in the steel would not take a weld.

 

Mine was broken at the top (the most likely place) and it heated there very fast. It could break at the other end, but the design probably makes that unlikely.

[uncledj]

Pulled the exhaust apart again today, planning on replacing the collector. Before pulling it apart I started the bike and quickly took temperature readings as it heated up. The front pipes heated at about the same rate, the collector seemed to heat evenly, except for where the front left pipe enters, which did heat up faster. I couldn't get a read on the rear pipes, but when I pulled the system apart, I slid under the bike and saw as much as I could, and both rear pipes looked ok on the inside, from what little I could see.

I inspected the insides of the front pipes, and with a small inspection mirror I was able to see into the pipe a little ways, and both looked good.

I'll change out the collector with one I'm hoping to get off of Dingy, and hopefully all that'll be left to do is sync the carbs and put the plastics back on, do a quick cleanup and I'm ready for next week's trip.

Wish me luck.....I really want to put this issue to rest.

Thanks all for the help so far.

[Flyinfool]

Silly question but I have to ask.

If the issue is that it is loud, why are you concentrating on the collector?

Have you inspected the mufflers?

[uncledj]

Silly question but I have to ask.

If the issue is that it is loud, why are you concentrating on the collector?

Have you inspected the mufflers?

The mufflers are the first thing I looked at.

It seemed (and seems) like I get more exhaust flow from the drain hole at the front of the left muffler than the right.

With that in mind, I thought the left muffler was bad, although I could see no evidence of it from looking into it. I ended up getting a replacement muffler on e-bay and put it on with no difference,....besides, the loud sound isn't coming from the rear of the bike, but rather from where the collector is.

When I start it and try to isolate where the sound's coming from, it comes down to the collector. I can neither see or feel any evidence of exhaust leakage from any of the connections, and it doesn't sound like an exhaust leak anyway....just loud, and something has changed, and isn't right.

I've removed all exhaust parts with the exception of the rear down pipes and inspected thoroughly and can find no reason for the change. I've seen on old threads where the collector baffles can break, causing such a problem, and that's what I'm down to.

Anyhoo, that's where I'm at with it.

[Midicat]

@uncledj

After reading your post in Gen 1 Tech Library on collector repair I was interested in the idea of a couple of sheet metal screws to hold the baffle in place. So, I thought I would give it a go. I have another collector but thought this might be simpler and also made sense to me. 

I gently laid the bike on the right side. Marked the tack welds on the bottom with a circle and drilled for screws on the marked dots. 

Broke 2 bits in the process but got it done. 

I stood her back up and started her.... Purrs like a cougar now. 😀 No more rattling! WOOHOO! 

Thank you for your fidgeting that brought this solution to my attention. 👍

 

 

[saddlebum]

I would have needed a dozen long screws. I cut the bottom off and found it full of loose pieces. I removed the loose pieces and welded the bottom back on.

[Squidley]

4 hours ago, saddlebum said:

I would have needed a dozen long screws. I cut the bottom off and found it full of loose pieces. I removed the loose pieces and welded the bottom back on.

I've done that a time or two 😏

[KIC]

I have a couple if you ever need another one..