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.

 

Yes there is play , the large hyvo chain is on the gear and you see in the picture the gears and this is what you see through the opening for the starter. Okay my opinion if your starter clutch slips it will not magically fix it's self . Yes rebuilding the starter motor is always a good idea , a fully charged battery and carbs synched all can help . The engine in my Seca was good for two years and engine had 38k on it went on a 300 mile ride by the last 100 miles could barely get it to crank just slipped . After I got home and the next day could not get it to hit at all just slipped. So did the deed one roller was galled pretty bad and the springs were shorter than my rebuild kit . I have not had any issues with cranking since i split the case and rebuilt starter clutch. The original engine to the bike had a slipping starter clutch as well 17k , I messed up and moved the crank shaft when I split the case and without the can tensioner in place it skipped timing. I still have not looked closely to see if a valve hit the piston two cylinders two and three are only showing 90 psi number one and four 130 Psi . Sorry did not mean to get off topic. Cheers

 

Slipping clutches will magically fix themselves when the slipping is due to the wrong oil. I used V-Twin 20W50 once, and the starter clutch wouldn't catch at all. Switched back to the Mobil 1 10W40 and it was fine.

I know what slipping sounds like and that's not at all what I'm trying to solve here. I'm trying to solve this hooting sound, which comes from the starter even when it's removed from the engine and I'm trying to solve that screech that's happening when the engine is running.

BTW, it would appear that what I am seeing in that photo is not the starter clutch, but is actually the idler gear. The clutch seems like I would need to pull the alternator rotor to be maybe able to see it.

 

OK. So, I've got the clutch plates out. Just want to verify where this bearing and collar go. I should have the parts tomorrow. Is this bearing behind the clutch basket - i.e. I would need to remove the 30mm nut, or are we talking about the flat bearing and shim that sit on the clutch rod?

 

There is slight side movement in the alternator starter clutch shaft l believe that is what it is. You might be able to check it but you would have to remove the alternator cover and stator. Then try and push pull on the rotor. Behind the alternator rotor is a bearing housing held by three torx bolts. Don't take that out to see the starter clutch incase the shaft comes with it. Then the starter clutch unit would then be loose in the crankcase in the pictures below. @tabaka45 post shows the seal replacement here, all you can see is the starter clutch chain and sprocket. Hope this helps.


https://xjbikes.com/forums/threads/...ith-pictures-applies-to-all-xj-models.108126/

 

You have to remove the 30mm nut to get the collar and bearing out. And on reassembly make sure the tabs are in their slots as this is how the oil pump is driven off the clutch basket.

 

Yes it is the idler gear, the starter clutch is behind the alternator rotor.

 

The bearing sits between the sleeve in the photograph and the clutch basket.




Needle roller bearing and sleeve below

 

I replaced the bearing and the collar. Both original parts looked fine. Then, after reassembly, I couldn't get the clutch to release. So I took it apart again, and removed the pressure plate, and it just seemed that a wet clutch with no oil is pretty sticky (I had tested release (or not) by putting it in gear and seeing if I could turn the back wheel with the clutch pulled in).

Anyway, after figuring/hoping that it would be better once there was oil in there, I put it back together again and could not get two of the pressure plat bolts to take the 7.2lbs of torque they're expected to take. Then one snapped.

On the bright side, the remaining piece of the bolt came out pretty easily. And I also have a suitable replacement on hand. On the not so bright side, I guess I'll need to helicoil at least two of those bolt holes. It was $32! for a M6 x 1 kit at Autozone, and it only came with three inserts, and not even the punch. For less, on Monday, I could have had a 131 piece thread repair from Amazon. The price of convenience...

So, going to take another stab at it now. Hopefully it goes smoothly from here.

 

OK. Rethreaded the two stripped holes, replaced the one broken bolt, and things went back together well enough. The clutch feels fine, and, sure enough, once some oil was in there, it released correctly. The bike also sounds fine, now. No idea if the bearing was really bad even though it looks OK. In any case, no screech, no hooting,... just the normal noises.

 

The bearing in my bike was exactly the same. It looked in good condition but noise disappeared once it was replaced.

 

When I stripped mine I found the bearing inside the oil pump drive sprocket (the narrow roller one) totally worn out - the rollers had flats on them, like they had been skidding around...

 

I checked mine when l had the engine dismantled and the oil pump one was fine. Do you know how many miles your bike had done?

 

Spoke too soon. Took the bike out for a ride. When I got back I turned it off in the driveway and went to open the garage door. When I restarted it, it was making a very clear whirring sound. I tried it a couple of times, and it kept doing it. Then after maybe the third try, it stopped.

I do think it's the starter clutch, and I think what's happening is that it's getting stuck engaged and driving the starter.

Or... maybe the solenoid is sticking? Would a stuck solenoid be enough to keep the starter engaged through the starter clutch? The whirring sound definitely varies with engine speed.

Edit: actually, a sticking solenoid doesn't make sense. If the solenoid were sticking, the starter would have continued cranking after I shut off the ignition switch.

 

That is unfortunate. I am not the best at electrical problems but if the solenoid were sticking how can the starter still crank when the ignition switch is shut off as the power supply to the live feeding the solenoid pigtail should be cut. If for example the solenoid was not working at all with the ignition switch on and power at the pigtail then jumping the solenoid contacts with a screwdriver should operate the starter motor. As I understand it on our XJ's the power flows from the battery to the main fuse then to the handlebar switch where it is distributed to the rest of the harness via the other fuses, although some wires are spliced together withinn the harness according to the wiring diagram.

A check if you can make sure nothing can get sucked into the crankcase is fitting a metal blanking plate of some sort over the starter motor opening and bump starting the bike a few times to see if the noise stops.

 

I suspect around 45k, but it's hard to be sure. I can't quite get my head around how this bearing might wear in this way.

 

Yes it's not got a lot of load on it surely turning the oil pump.

 

No, that's incorrect. Power to the starter comes directly off the battery. The low current trigger to the solenoid is through the fuse box and ignition switch, but the high current side is not switched or fused. If you have a Haynes manual, take a look at the right side of the page where you will see the heavy line going from the battery, across the solenoid, and to the starter.

If you still don't believe me, just pull the side panel off your bike with the key off and jumper the two large contacts with a screwdriver or wrench... the starter will crank, but the bike won't start because ignition is disabled.

To be clear, a sticking solenoid is one that stays closed after power to its coil is removed.

 

Lol yes you are correct of course the heavy red wire from the starter goes to the solenoid. All l had to do was look at my bike before my last post. If the signal wire was in place of the heavy red wire with the current the starter motor would draw would cause the wire to overheat. Told you l was no electrical guru

 

Well... some unhappy new developments:

I rode to work today. When I was ready to head home the bike started fine, but I thought I maybe heard that whine like I'd heard before. I went see if the start button might have been stuck in, and, I guess I must have pressed it. I heard a clunk from the engine and it died. The starter now has difficulty turning the engine, and it won't start. Attempting to bump start it doesn't work at all. Even with a decent downhill slope the bike just stops when dropping the clutch. Waiting for a tow truck now.

 

Next steps are going to be to pull the starter, to see whether it's damaged... if I can even tell... and pull the alternator, so I can at least get a look at the starter clutch, but, at this point, I'm pretty resigned to pulling the engine and getting invasive.

 

My starter button does nothing if the engine is running. It sounds like yours engaged the starter which stopped the rotation of the motor and is still engaged, keeping the motor from starting even with a bump start. Could this be possible?

 

Next >

Before you remove the alternator rotor can you use a socket on the rotor nut and try and turn the rotor anticlockwise to see if it locks because the starter clutch dowels should be jamming in the narrow end of the clutch hub ramp? I know it might have to spin faster to catch but it is worth a try. It should turn clockwise easier if it is not driving the starter motor I think although I could be wrong.

 

This a case where bolts backed out of the starter clutch causing it to lock up:

https://www.xjbikes.com/forums/threads/starter-motor-issues.67016/page-2

 

I don't think so. The starter switch and solenoid should be active when the bike is running in neutral, as mine was. But a freely spinning starter clutch should, I think, prevent any interaction if the starter is triggered while the engine is running. I think this is just more evidence that my starter clutch is not releasing correctly.

I think it's more because of a different design, but my daughter managed to break her starter gear and tear up the stator in the alternator on her Ninja 250... by the same method of pressing the Start button while the engine was running.

 

I'll give that a try after I've pulled the starter. I know what the behavior should be for the idler gear. I'll see whether it's locked to the crank, and whether turning the alternator can make any difference there.

 

I don't think the starter clutch is releasing correctly either.

 

I pulled the starter. It seems OK. The idler gear is not idling. It's stuck solid. Even if I put it in gear and rotate the rear wheel, the idler will not move. In some way the idler, and the starter clutch, are stuck pretty solidly.

 

Here's what I can see after pulling the rotor and the alternator shaft.

I was pleased to find that the center bolt from the alternator puller I'd bought for my daughter's Ninja 250 was a perfect fit for the XJ rotor.

On the other hand, I'm now left thinking: really?! they couldn't make the alternator bearing plate big enough to allow replacement of the starter clutch?!

Once the alternator shaft was out, the idler gear spins easily. I'm not sure yet what part was grabbing. It was not the starter, as, with the starter out, the crank was still tough to turn... but it seems to move more easily with the alternator shaft out.

 

This evening's progress.

I was a bit annoyed to have to remove the dental tube for the oil cooler / spin-on adapter. On the one hand I had bought some longer ones because I thought an extra 5mm would be good. On the other, the Loctite Red really was doing a great job of holding the existing one in place. But, I couldn't get it to clear the front engine mounts without removing the valve cover, and it seemed like a better idea to remove the dental tube.

 

The culprit