Starter Clutch?

I’ve read many forums on here and think I have a starter clutch issue. I have an XJ750 that I bought unassembled and reassembled before I knew much and thankfully found this site and got it running and started riding it. So, thank you!

Unfortunately, my bike no longer starts. It squeals/slips at a higher pitched sound when I try to start it, like somethjng is slipping. The issue started while it was running and quickly shut off mid-idle with the same squealing/screeching sound.

There were times I would try to start the bike with a whizz sound, but the motor wouldn’t turn.

Here is what I’ve done so far:
-bought new battery. It was dying really quick on start and needed a new one anyways.
-changed oil (15w40)
-bought new starter motor as the other was toast.

I would rather not crack the engine open, but thinking I might have to.

Any suggestions would be helpful. Thinking it might be the starter clutch or something to do with my clutch plates but not really sure?

 

Doesn’t sound like the typical starter clutch failure to me. Unfortunately, I don’t have any good ideas what it could be.

Could you get a video of it?

 

I think there are 2 main noises most people hear.
1. Starter Clutch slipping - grumbling rocks type of thing.
2. Starter Clutch not disengaging - hi pitched whining (starter motor driven by the crank)

1. can be 3 things.
Bad oil - had this happen (easiest fix)
Bad springs and bits in the starter clutch - haven't had this happen
Cracked starter clutch hub - had this happen.

2. I haven't seen a breakdown or had this happen myself....
But you'd think most of these, except the oil issue, come down to the same fix, split the engine

 

I will take a video tonight and post.

 

I said higher pitched as the other videos sound lower like rocks in a can. My sound is more like slipping or a higher grinding sound. I will post a video tonight. Hopefully that helps.

I did put a synthetic oil in when the problem first started and the starter seemed to be slipping, but have since changed back. I also put sea foam in the oil in hopes it might help as per other threads.

 

I went to go make a video and had pulled my starter motor off to see if that might be the problem. To record the video I put it back on and all I get is a click. If I touch a screwdriver between the two bolts on the solenoid the engine turns over and the starter motor turns.

Solenoid not working? Checked connections and no change. New problem to solve I guess…

 

Exactly.

 

I have been moving and just got back to the bike today.

Threw a new solenoid on, charged the battery and cranked the engine. It turned and then didn’t stop turning over. The starter motor just kept turning and the solenoid started to smoke. Yikes!!!

I quickly got the battery connections off and eventually once connections were removed the starter stopped turning.

I don’t think it’s the solenoid as this is my third new solenoid I’ve tried.

It seems like my starter motor is drawing too much power from the solenoid. Any thoughts?

 

It could be something is shorted inside the starter motor. You can open it up and have a look, maybe something obvious sticks out. Releasing the start button removes power from the solenoid, which should break the circuit between the battery and the starter motor; if not, then the contacts in the solenoid have been welded together (!!) or the solenoid is defective. It would take a LOT of current to weld the solenoid contacts together..........

 

I’ll check the start motor tomorrow, but the fact that the bike kept starting even after the start button was releasing was unusual.

 

It could also be that the START button was actually sticking in its "pushed in" position for some reason, or the internal contact wasn't releasing (even if the button popped out).....

 

I thought about this, but there is another issue where I keep trying to get the engine to turn over and the coil burns out or just clicks. Especially when I put on a battery charger. I’ll check the starter button too.

 

Pull the spark plugs and engage 3rd gear, try to push the bike along - see if the engine turns over. It sounds like something seized - no idea what though..

 

Why third gear? More curious than anything. I do think it's my starter, because that's what I replaced, but will try both tomorrow. I finally have a day off to work on the bike.

 

2nd or 3rd, no matter, just so you can push the engine around. The point (I obviously didn't make clear) is so that it proves it's not the engine, alternator or something else causing this. The reason being, your original post said it stopped whilst running - this would not have been due to the starter motor...

 

Alright. I put it in second gear, engaged the clutch, and rolled the bike so assuming the engine turned over. Don’t think it’s seized unless I need to do this with the clutch disengaged, but then it wouldn’t move anyways.

I opened up the replacement starter and most looked normal, but there was a ton of black powder in the bottom where all the electric connections are held. I assume that this powder was meant to help with something, however, everything was really dirty so not sure. Much dirtier than my first starter motor.

I did notice the armature is very smooth where my older one has a bit of profile around the outside (pictures attached). I’m not exactly sure what I’m looking for, but I wonder if this might be an issue. I’m gonna upload some pictures to hopefully help understand my ramblings.

Opened up my stater button and didn’t see any issues that would cause it to stick so will have to attach the starter motor again to know if it will have the same problem as I try to start it again. I’m still under the impression that something to do with the starter is causing it to draw too much power. Hence, my suspicions with the starter motor.

Any help would be much appreciated.

 

Any help would be much appreciated.
Well I am trying, but youre not listening.
You need to turn the engine over - it should turn over in 3rd gear, with the plugs out. Why pull in the clutch? If it doesn't turn over get a spanner on the crank and carefully try to turn it over that way.

 

I pulled the spark plugs, shifted into third and the engine does not move when I try to push it. The back tire drags until I engage the clutch.

I did pull the ignition cover off and cranked the engine manually. It turned over with some effort in third, but it did turn over. I did the valve shims this summer and it was cranking over then too.

 

Rear tire dragging means engine not turning. If using a wrench on the crank manually, it should be in neutral, else you will be trying to roll the bike.

 

I’m assuming this means I have something blocking my engine from turning over and need to open the engine up. I hope not, but I’m thinking this is the case.

 

All that black dust in the starter motor is carbon which has been shaved off the brushes.
It needs to be removed and is highly conductive.
It also means you may need new brushes and/or a commutator resurface.

Basically the outer coil magnetises and the brushes connect to the armature, the spinning bit, and magnetise that an in opposing fashion to the outer coil to make it spin.

So yeah, commutators, the copper bits on the armature, get rough from brushes not seating properly and then arc and the brushes wear out faster.

Also at this point the excessive amperage can cause huge heat and armature varnish melts, and then it's toast.

Hmmm... I may not be helping but brush based electric motors need maintenance.

 

I got the engine to turn over manually, but by cranking it like you said. It did not turn over when in third gear with the spark plugs out. Would this give any indication about the problem?

 

@jloeve can you turn the back wheel by hand with the transmission in neutral? If not I would think that would indicate something like the rear brake being stuck on or rusted to the brake drum. Did the engine turn fairly easily with the wrench? It should not turn freely but with some mechanical resistance but not take a lot of strength to turn with the plugs out. If the bike has been sitting for an extended period the clutch plates can be stuck together as well adding the resistance of turning the transmission gears.

 

I can turn the wheel in neutral.

The engine turns quite easily with similar resistance to when I did the valve shims a few months ago. Still a bit of force needed, but nothing to difficult.

 

If you open the clutch pack zip tie the lever on to the handle bar you can try separating the clutch plates with a screwdriver. It should not need a lot of force to separate them if they are stuck as @Fuller56 stated. If you decide to take the cover off and take the plates out use new bolts and torque them to spec.

 

Are you suggesting the plates are stuck together?

 

We should go back to this point.
Solenoid fails.
New solenoid and it sounds like it has welded itself internally closed from over current draw.

The starter motor.
Pull it off.
Can you spin it by hand? (It will move freely or poorly)
These things have bronze bearings and super gearing and draw a huge amount of amps.
So...
If you can't turn it.
Jam it in a vice and use some jumper cables to see how it spins.
It ought to violently take off and then slow down on removing the cables.

If it does cool.
If not you should strip that right down and clean everything and regrease all bearings gears.

The commutator/brushes is always the killer for this stuff electrically and if the starter is not free spinning then it is even worse current wise for the solenoid also.

https://xj.diagnostic.net.au/images/starter_motor.mp4

https://www.xj4ever.com/starter brush replacement.pdf

 

It is possible.

 

Had a chance to test a few things on the bike. I did get a chance to turn the engine over a number of times manually. I then replaced the solenoid again and turned the engine over. It has spark and is getting fuel.

I will pull the starter and open it up as when I installed it I couldn’t spin it by hand. I remember wondering if that was normal.

I will separate the clutch plates with the technique listed above.

Lastly, I posted a video of my bike trying to start. Maybe the sounds can help diagnose things? Here’s the video: https://youtube.com/shorts/BokRPWPTV48?si=lVzE1e2DqXgJGeJc

 

Not sure but I think when trying to turn the output gear it is normal to not turn by hand because of the gear reduction internally to the starter, maybe someone has one laying around to verify - at the very least it would take a lot of force to turn the output gear.

 

I cannot turn the gear by hand.

 

If the back tyre is dragging until you pull the clutch lever in the plates are not stuck.

 

Good to know. They wheel releases when I pull the clutch lever in.

 

You can but generally not on most of the starter motors before refurb.
These 2 I refurbed on a rainy day because I am insane.
Huge difference to an old gunked up starter

https://xj.diagnostic.net.au/images/starter_motor.mp4

 

Okay, that is much different than what I’m experiencing. Is this the grease you put on it, because I have two and they are both no where near that easy to spin.

 

Think about 40 year old grease and dry bronze bearings plus contamination from the brush carbon.

I basically pulled it all apart, removed all the old grease, oiled up the bronze bushes and repacked the gears with new grease and that is the end result.
Before that they felt seized pretty much.

Obviously I resurfaced the commutators and put in new brushes while I was there, but that's another story.

 

Oh yeah.
As a tip.
Pulling the starter apart and reassembling is pretty funky.
They have permanent magnets instead of a main coil. So that armature really wants to be in there.
If you do a refurb you will know what I mean.

 

I saw a post where the brushes were replaced above and they seemed almost twice the size of mine. Clearly wear has taken place. Might be time for me to full refurb and not just grease them.

 

I hear you. I also think that when I reassembled the starter motor that I could have tightened the longer bolts more that run down the side. I didn’t want to strip them, but in doing so I think they were a little too loose. Second time I tightened a bit more and had better results. I think this may have been my issue the first time.

 

Oil up those bronze bushes/bearings and get the armature free spinning like a top before you put it all back together with the gears.
Pretty sure, like an old fan that starts squeaking and seizes up, that is the main drag on these.

 

I put a little copper grease on the two external starter motor bolts threads.

 

Okay. I cleaned out the black gunk from the starter motor, greased it up, and ensured that the gear at the top could turn easily, which it now does. Starter motor, solenoid, work every time.

However, I still can’t start the bike. The engine is turning (maybe not fast enough to start), I have spark, compression, and fuel. Yet… nothing. BUT, there is this infrequent sound that sounds like slipping when I try to start it. I’m not sure it is slipping, but it doesn’t sound good.

Which leads me to my original question. Could the starter clutch be making this sound? Is my starter motor still not working properly?

It’s not the ‘pile of rocks’ sound from other videos. More of a slipping or some type of rubbing sound.

I posted a video here: https://youtube.com/shorts/dAAL7UlDAOA?si=cQIfBkW3LNOTJvDx

Sound is coming from the left side of the bike.

 

The squeaking stopped when I pulled the spark plugs to check compression again. Came back once I placed the plugs back in. I have spark, but shot some quick start in to see if it jumps at all. Nothing happened. I’m very confused what’s going on.

Compression was around 100, 100, 100, 90. Cold engine and cold outside.

 

.

So this squeeling noise is what I don't like. It did it whilst running? And now also when trying to start? The same noise?

If so I think you need to strip the motor to check you haven't done something wrong....

 

It stopped at some point and now won’t start. I’m not sure if the noise would continue if it started, because I haven’t got it to fire up yet. I was going to try to bump start it.

When you say strip the motor. Are you saying just the valve cover and check in there or take the whole thing out and look through it? I’ve not yet cracked the engine case.

 

Check that the cam chain hasn't slipped.
Move the reluctor to TDC and check the cams are in the right position.

 

Starter clutch can of rocks sound. Are your camshafts stopping turning? Probably need to split your engine cases.

 

I'm trying to help you here, but you're ignoring my questions...

So answer all three questions honestly. If the answer to all three is yes then you need to split the engine - it should not speal, or stop itself when it squeals.
I'd add another question though - is the squaling escaping gases? Like a head gasket failed? This might make life easier for you - taking the top end off is a sight easier than splitting the bottom end. But, a leaking head gasket shouldn't affect it cranking over on the starter.

 

I have finally got up the courage to open the engine up. I’ve taken the valve cover off many times, but never pulled the engine completely out.

The squealing is coming from the lower portion of the engine and not from the head gasket. That would be a nice easy fix.

Before opening, I pulled some things off and noticed that my timing pointer is missing. Is it good enough to shot for the centre of the screw hole? If so, everything is aligned. (See picture)