My Seca 750 is making some awful noises

There's a video here: https://drive.google.com/drive/folders/1ShBFEtFi6dOKiahWIYK-ZTj752z7E6Mc?usp=sharing

This is my fuel-injected Seca 750. I recently built a new manifold and fuel rail for it. I had had a problem last year where the timing chain had jumped a tooth. I reset it, checked everything, and adjusted the valve clearances. I didn't find anything obviously wrong with the chain or the tensioner. Compression was OK. Bike has about 31000 miles on it.

It was down for quite some time as I was building the new manifold, though. This is a box plenum style instead of more of a header style, and the new one is welded out of aluminum while the old one was soldered with brass and copper. It's not pretty, but I'm happy with how it came out.

Anyway, I got it back together a couple of weeks ago and took a short test ride, which was fine. Last week I rode it to work and back, and it was pretty great. Especially really good mid-band torque. Today I did some adjustments to the tune, and suddenly started hearing some nasty grinding sounds.

There are two annoying sounds in the video. One is a bit of a howl or a hooting sound. That is something I started noticing after getting the bike back together. It only seems to do it around when it's cranking, or just as it's shut off. When running the bike sounded very normal up till tonight. The other sound is a high pitched shriek/squeal that sounds like a chain dragging on something. Both worry me, but certainly more the shriek. Any ideas what that might be? Alternator chain? Timing chain?

Oh, there's also a sort of grunting bullfrog sound. That's the idle air valve. It's normal for this build. You hear it right at the end of the video.

Thanks, Paul

 

Could this be all from the starter clutch?

 

Take the pick up coil cover off to see if the crank is turning every time you press the starter button. Sounds like it's slipping to me.

 

Never seen fuel injection on an XJ. Great work.

 

The engine is starting. But it's making this awful screech. That's what I want to know the source of.

 

I wonder if it is your clutch basket bearing. My 900 was making a similar noise and that was the cause.

 

Hmm... how did you narrow it down and verify it? That's easer that the starter clutch...

 

I had a stethoscope l put on the clutch case and could hear the noise. There was play in the clutch basket when l stripped it down.

 

This is the thread l posted.

https://xjbikes.com/forums/threads/rattling-noise-on-start-up-yamaha-xj-900f.119637/

 

Thanks. I guess I'll start with draining the oil, pulling the clutch cover, and removing the clutch. If I can't see an obvious problem there, I think I can put it back together without the clutch and see whether the noise is still the same.

 

Remember your clutch basket drives the oil pump.

 

Here's what it sounds like cranking with the plugs out, the clutch cover off, and the ECU disconnected.

https://drive.google.com/file/d/1NlO_seHIY1GZJZjT7de4etMINTCFFie3/view?usp=sharing

The hooting sound seems to be the starter or the starter clutch. The clutch and its surroundings look very clean, but I don't know whether that says anything about the condition of its bearing.

I didn't hear the screeching here, so I think that's probably something that happens only when the engine is running... which makes me wonder again about the starter clutch.

 

My clutch looked the same even though the bearing was worn and the bearing only made a noise when opening the throttle. Have you noticed any evidence of the starter clutch not turning the crankshaft every time you operate the starter? Your clutch is spinning all the time during cranking in your second video. But you have the plugs out so no compression. First video the compression would be there. Put the plugs back in and spin the engine a few times to see if the clutch basket keeps spinning. Hopefully it is the clutch hub bearing as it is an easy fix. If the starter clutch is not slipping at all l would strip the clutch and check the bearing. My bearing looked in good condition but there was a lot of side movement. I replaced it and noise vanished. Your bike has fuel injection too. Is there anything that can make any noises with that setup? Unlikely l know just wondering since your machine is modified.

If the screech is only happening when the engine is running that is when your starter clutch rollers are not locking onto the crankshaft so it cannot be the starter clutch surely. A worn starter clutch shows symptoms during cranking when the rollers are meant to be locked, when the engine fires they become unlocked because of that ramp. If the bike was cranking all the time hot and cold engine with no starter clutch slippage it cannot be the starter clutch surely.

 

I cannot view videos get an error message. But if you skipped timing , here are possible problems, you chain guide might have started breaking , possible that a valve kissed a piston so valve could be bent slightly , even tough you state compression is good ( I fear this what happened to one of my engines when I did starter clutch.

 

I just pulled the starter and ran it by itself. It's definitely responsible for the hooting sound. So, certainly going to do a starter rebuild in parallel with trying to find the cause of the screech.

 

The starter clutch teeth look ok, and it spins easily in one direction and grabs in the other, but it has a bit of play if I push and pull it perpendicular to its direction of rotation. Is that normal?

 

The starter clutch has three rollers and springs the teeth are on the outer edge you will not be able to see much when it slips the rollers will not engage properly the springs get weak . Attached are pictures of the starter clutch and the repair kit I used.

 

Here's what I can see

 

That is all you will see of the starter clutch.

 

I was hoping somebody could tell me whether that play back and forth is normal.