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Discussion Starter · #1 ·
Been lurking for about a year since I first got my CX. First I gotta say thanks to the insane amount of resources here. My mechanic experience is limited to changing the oil in my car and rebuilding a carb on a XR50 when I was 13. So let's assume I have no knowledge of this sort of stuff. I downloaded all the manuals that I could find on the site, as well as all the magazine articles on rebuilds that I could find. I've read through them and have a basic understanding of what I think needs to be done. But ultimately I'm asking you guys what you think needs to happen.

So here's the situation:
I bought the bike last May from the third owner. It's a 1979 CX500E, serial 2100991. No punch marks that I can find to indicate it underwent a recall service. He said he hadn't gone through the carbs, but it ran fine so I wasn't in a rush. I rode it daily until September when it died while riding it to work. I pulled over, it started right back up, ran fine for about 5 minutes, then died in a similar manner. It started back up and I made it the last couple of blocks to work without it dying. I took it to a local shop and he diagnosed that there were small holes in the rubber carb diaphragms, so he ordered a new set and installed it. Test drove it around the parking lot for a few minutes at various RPMs and it seemed fine. I was riding it home and it died in the same manner as before. The shop picked it up and went through it again. He double checked the carbs and said they were fine, so he adjusted the valves and that seemed to solve it. I rode it home, but the following day it died again. So again, he picked it up, and this time he said that he had just not properly attached something between the throttle and carbs. He said he fixed it, but when I went to test ride it, I rode it and it wasn't dying but it seemed to be revving really slowly and I couldn't get it above 4500-5000 RPM. The engine had also developed a knock at anything above around 2000 RPMS, regardless of which gear or if it was in neutral. It was about 40 degrees at the time, and we let it run for a while to warm up, but nothing changed. I only lived a couple of blocks away from the shop at the time, so he suggested that I could ride it home and try to get it running better the next day when it was warmer. I stupidly agreed, and on my way home the bike was whining weird, the exhaust smelled wrong, and it died within a block of the shop. It was 9 PM and I knew that the guy had left his shop, so I just pushed it home.

The next day I let it sit in the sun for a few hours, then started it. It seemed to be running a little better, but the knock was still there and I could tell that there was still an issue regarding RPMs. I was riding it at about 3500 RPMs(couldn't get it above that) and about 15 mph when I heard a really loud click-click-click sound coming from what seemed like the rear of the engine, on the left side. Immediately pulled in the clutch, pulled off the road, the bike kept running but the clicking stopped. I tried to let off the clutch, but as soon as I did it sounded like a chain was flailing around inside my engine. I pushed it home. Unfortunately, I never got to settle with the mechanic because the next week I had to move, and the bike came with me. It sat from that time in early November until about a week ago when I dusted it off.

I started the bike up, and didn't seem to have the previous RPM issues. I never put the bike in gear, but the engine sounded normal, aside from the same knocking noises, and no chain bouncing around sounds either.

Sorry for the novel, but I wanted to get a clear history of the bike out there. I also have videos with the knocking sound that I'll post when I get the chance.

So where do I start? From my readings on the forum, the sounds seem like they could be the typical cam chain issues. I've read the thread on the wiki that sounds almost exactly like the situation with the noises I heard. But I'm less sure about the first issues, the bike dying and running at weird RPMs. I attempted to look through the porthole to check the cam bolt head like the wiki thread instructs, but I couldn't make sense of the mirror image. The dental mirror I was using was too big to completely fit through the hole, so I'll pick up a smaller one when I get the chance so I can get a better view. After recording the knocking sounds, I got eager and jumped into the teardown. In order to pull the seat, I had to pull the rear wheel out because the only bolt that connected it to the frame was attached to the bottom of the seat and went through a roughly cut hole in the fender, and wasn't accessible with a wrench or socket with the wheel on. I pulled the gas tank, drained and pulled the radiator, used a M14 x 1.5 45 bolt to pop the fan out, and am half way through removing the fan shroud.

I've been taking a ton of pictures and have labeled all the parts as I pull them off. So that's where I'm at. Any and all suggestions with how to proceed will be appreciated!
 

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first a 79 was not part of the cam chain recall so no punch marks needed that was only on some 78s

how many miles are on the bike?

where does the knock seem to come from in the motor front or back one side or the other?

stop taking things apart if you dont know what you are looking for
 

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Discussion Starter · #3 ·
Thanks for the reply. The speedo reads 11,387, but the PO couldn't say whether it was accurate. The knock seems to be coming from the center of the rear of the engine. And yeah, that's why I stopped pulling stuff off once I hit the fan shroud. Speaking of, the fan did have pretty bad stress cracks on the back of it, so I'm thinking about putting in an electric fan. I'm hoping to use this as a "get to know my bike experience" and clean it up a bit.
 
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