Clutch situation driving me crazy
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Thu Jun 11, 2020 5:37 am quote
Bluecati wrote:
Behind the clutch is a washer...some are thick some are thin....and can be confused with the washer on the rear wheel.......maybe you accidentally sweapped them??? or ordered the wrong one

On the end of the clutch itself is a replaceable brass bush/ ring designed to wear down.....lots of peeps ignore that bit..replace it with new .....even a few mm worn down will ,do what your clutch is doing

The brass pusher in the clutch cover also wear down so get a new one

Thrust plates can be bent.or worn too

all new bits then report back
Also, that is a hardened washer with a bevel on the ID on one side that must be installed facing in towards the flywheel to allow for the rounded step on the crank. Get it backwards and it can crack or even scatter shrapnel causing lots of grief. But it doesn't sound like that's your problem. Check it's on right anyway.

Your brass plunger and pressure plate look normal to me, I'd still use 'em.

You could do yourself a favor to make your life easier and get a Cosa clutch nut as well if you're getting parts.

http://www.scootermercato.com/Scooter-Parts/Clutch-Misc-Parts/212141
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Thu Jun 11, 2020 10:33 pm quote
HKsprint wrote:
chilidog wrote:
This then pushes in the clutch assembly causing the cork pads to apply pressure to their paired discs... to do what?
When you pull the clutch lever you're compressing the springs, relieving the compression force holding the plates together. The plates then slip/separate. As alternate plates are dogged to the engine drive side and the gearbox drive side, this slipping breaks the drive link from the engine to the gearbox.
So, when plates or springs wear, the clutch will slip. Conversely, if the cable stretches, the clutch won't disengage, and changing gear gets clunky...
Hope that helps!
HKsprint - this is really helpful. Thank you for the explanation. So then a possibility for my original problem... stalling when I squeeze the clutch handle. Could it mean that my assembly is too rigid(springs are too tight) so that the pressure from the arm to plunger against the pressure plate creates so much friction that it stalls the engine? The only thing is that I am not seeing any excessive wear on the plunger.
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Thu Jun 11, 2020 11:00 pm quote
MJRally wrote:
You mentioned this is a rebuild. Did you use the old clutch spacer/ oil pump drive cog? Or did you buy a replacement?

Like you mentioned the pressure plate is worn. When you can run a flat screwdriver over it and feel edges/ low spots its time to replace it.
I pulled the assembly out again and dismantled it completely. Everything looks good as it was rebuilt years ago and then sat. I am using the oil pump drive cog as a spacer as my scoot is an automatic. The cog looked really good, no wear on the teeth and smooth on both sides.

The expendable parts(brass looking) of the clutch are all clean and good with no excessive wear. I think I should get a replacement of the pressure plate for the next time I open it up as there is a ridge around the edge, but I don't think this should be causing my stalling issue?

On a side note- how tight should the brass bushing be seated on the clutch center stem? Should that be able to move freely as it currently isn't.

20200611_173551.jpg
clutch assembly internal brass washer

20200611_173619.jpg
brass bushing which is pressed on pretty tightly. Should it be freely moving?

20200611_173602.jpg

Hooked
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Thu Jun 11, 2020 11:56 pm quote
@chilidog -- that brass bushing should be immobile, pressed-on, not spinnable. You can rule that out as a source of the problem.
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Fri Jun 12, 2020 10:32 pm quote
Could it mean that my assembly is too rigid(springs are too tight) so that the pressure from the arm to plunger against the pressure plate creates so much friction that it stalls the engine? The only thing is that I am not seeing any excessive wear on the plunger.[/quote]

The interface between the plunger and the clutch centre is well lubricated and, if itís showing no signs of wear, probably wonít be a cause of high friction.
If you have extra heavy-duty springs the friction would increase, but Iíd be surprised if it was anywhere close to being enough to stall the engine.
The only other thing I can think of has been mentioned above by JimVM and Darren.H - crank shift. When you pull the clutch lever, the force to compress the clutch springs is applied axially to the crankshaft. I know youíve checked for this, but I wasnít clear if youíve checked for movement with everything assembled? The force exerted by the mechanism is many times more than youíd be able to apply by hand to the end of the crank. With the engine stopped youíd need to put one hand on the flywheel then pull and release the clutch lever a few times. Any axial movement of the flywheel will mean the crank is shifting. If none is apparent, put it in gear and repeat the process whilst rocking the bike (or jogging the back wheel if itís off the ground) back and forth just a little, this may require some help unless youíve got three hands... This will ensure that any end float is not hanging up on the helical drive gear to the gearbox.
In the meantime, Iíll keep thinking...
Best of luck.
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Wed Jun 17, 2020 7:26 am quote
So here is an update...
Thanks HKsprint for the recommendations. Also very helpful to get different perspectives and advice from experience. I have been working the clutch issue a bit this past few days but just seem to be digging myself in a deeper hole.

There is now something wrong with the clutch where it is not compressing to allow gears to change. I was really careful to make sure all was right the last time I had the assembly out and to make sure it was all went back together correctly and moved well before wrenching it in place. I gotta open that up again for the 3rd time...

I will need to get this fixed before I can make a proper test as recommented.
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Wed Jun 17, 2020 7:43 am quote
One thing that can be an issue although I think this is highly unlikely is that the clutch disks can bind up on the guides inside the clutch assembly. I would pull the clutch apart and make sure everything inside the clutch moves freely inside the housing without the springs.

Sorry this has been such a pain, its always frustrating to be so close and yet feel like the end is so far away.

Hal
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Wed Jun 17, 2020 9:14 am quote
This is a real mystery, I wish I could offer something new but the guys all gave some great recommendations. Being a Canuck here I think I would have threw in the towel and ordered an entire new clutch by now and through it in there just to rule out.
Do you know anyone with a clutch sitting on the bench you can borrow for test purposes ?
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Mon Oct 12, 2020 9:00 pm quote
It has been a while away but now back
My last post was while back as I was away from the scoot for many months. I am still back at it trying to figure out the issue with my engine cutting out every time I start to pull in the clutch handle. So one thing I tried to narrow down that it is an electrical issue... I jumped a spark plug tester between the plug and the plug wire. The tester has a glass so you can easily see the current. When I pull in the handle the current stops along with my scoot. So I begun the tear down of all the wiring from the bars and head lamp. The best guess is that somehow the cable throttle is pushing on a wire that is bare which causes the short to kill the spark. I really don't buy this but not sure where else to look. I have also drained my gas tank and pulled it. Spent about 15min with my hand up the frame trying to feel if there is any pinching of the main loom. From the picture you can see through the speedo hole a top down view. My clutch cable is no where near the main wire loom which is completely protected in a sheath. I guess I am grasping for any thoughts before I try and fish the loom back out for an inspection.

20201012_183149.jpg
cable on the left is the clutch. On the right are the main wire looms. They are running up the frame in two different places.

Jet Eye Master
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Mon Oct 12, 2020 10:43 pm quote
When you did the electronic ignition conversion what parts did you use? Might be some issue with lining up the pickup coil.
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Tue Oct 13, 2020 6:07 am quote
Jack221 wrote:
When you did the electronic ignition conversion what parts did you use? Might be some issue with lining up the pickup coil.
I bought the BGM conversion kit and have their wire loom as well.
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Tue Oct 13, 2020 8:12 am quote
How long have you had that pressure plate? It's showing excess wear, which happens when the clutch arm is keeping pressure on the clutch even when it's in gear. That could be caused if the cable it over-tightened, and will eventually kill the brass plunger, and will cause super-rough shifting, which will then accelerate cruciform & gear wear, which is a split-the-cases event.

Other things to check:
- Is the clutch spacer/washer on backwards? It has a bevel on the inner side and is intended to only fit one way. If it's on backwards, it will eventually crack an shatter, which could be Very Bad, depending on where the pieces land.
- Does the clutch arm move easily, and does it fully return when you release the pressure? It should move with almost no resistance if the clutch cover is off. If that's not the case, then you need to rebuild the clutch cover/arm.

I'd make sure all of those pieces are correct before I did more investigation of the crank for movement unless it's visible when you depress the clutch.
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Tue Oct 13, 2020 11:00 pm quote
chilidog wrote:
Jack221 wrote:
When you did the electronic ignition conversion what parts did you use? Might be some issue with lining up the pickup coil.
I bought the BGM conversion kit and have their wire loom as well.
Well, in that case, misalignment of the pickup coil to flywheel just moved to the top of the most likely suspect list. Easy to fix just need to do some measuring.
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Wed Oct 14, 2020 6:37 am quote
Jack221 wrote:
Well, in that case, misalignment of the pickup coil to flywheel just moved to the top of the most likely suspect list. Easy to fix just need to do some measuring.
So can you explain a bit more on how that is causing my engine dying when I pull in my clutch handle? The scooter is idling well, and I can give it throttle. Just when I squeeze the clutch handle the scoot dies like something is grounding it out. I guess if I had play in my shaft and through the case the stator somehow touches something to ground it out?
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Wed Oct 14, 2020 7:41 am quote
There is always movement in the main crank bearing. Pulling the clutch moves the flywheel. Your pickup will be mounted too low. It will need to be spaced away from the backplate. How thick the spacer will be is another story.
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Wed Oct 14, 2020 10:24 am quote
Just a thought... Can you release the clutch while the motor's still turning and start it up again ? Can you make it quit/run/quit/run ? If so, how far do you have to pull the lever for it to die ?
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Wed Oct 14, 2020 7:52 pm quote
Moto64 wrote:
Just a thought... Can you release the clutch while the motor's still turning and start it up again ? Can you make it quit/run/quit/run ? If so, how far do you have to pull the lever for it to die ?
I went online to buy another set of clutch parts, the works except for the basket. I will check again to see if I can find any movement as well as replace the clutch.

I just have to barely start to squeeze the clutch handle before it dies, I mean it doesn't take much. When it dies, I start the scoot again, no problems. It dies I start it again and it idles very well. I can coast start by popping the clutch in 2nd or 3rd but if I try and shift, it dies.

So there is one situation that now I am wondering if it caused all of this. I was riding shifting from 3rd to 4th and the tired completely locked up going about 35mph. Didn't think anything of it, maybe it was my fault with a miss shift. Scoot started up and finished the ride not problems. After that event the issue started, and kept getting worse. It was intermittent but now it is all the time. You have seen my clutch assembly in pieces. Everything looks decent... so I am not sure if this is the cause. Thoughts?
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Thu Oct 15, 2020 2:52 am quote
chilidog wrote:
Moto64 wrote:
Just a thought... Can you release the clutch while the motor's still turning and start it up again ? Can you make it quit/run/quit/run ? If so, how far do you have to pull the lever for it to die ?
I went online to buy another set of clutch parts, the works except for the basket. I will check again to see if I can find any movement as well as replace the clutch.

I just have to barely start to squeeze the clutch handle before it dies, I mean it doesn't take much. When it dies, I start the scoot again, no problems. It dies I start it again and it idles very well. I can coast start by popping the clutch in 2nd or 3rd but if I try and shift, it dies.

So there is one situation that now I am wondering if it caused all of this. I was riding shifting from 3rd to 4th and the tired completely locked up going about 35mph. Didn't think anything of it, maybe it was my fault with a miss shift. Scoot started up and finished the ride not problems. After that event the issue started, and kept getting worse. It was intermittent but now it is all the time. You have seen my clutch assembly in pieces. Everything looks decent... so I am not sure if this is the cause. Thoughts?
When you barely pull and let go does it keep running? If something is moving it would do it when you just start to pull and take up slack. That could get back to something moving.
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Thu Oct 15, 2020 3:24 am quote
This very curious.
I find it hard to believe that the slightest pull on the lever could cause enough friction inside the motor to stall it. Certainly not at the center of the clutch release bushing/plate. If the clutch bell was grinding on the case or gear or the flywheel against the case I'd think you would feel/hear the grinding/friction and I'd think the power of the motor would over-ride the friction. Is there any sign of metal swarf in the gear oil ? A magnet would tell you if it is steel or alloy.
If it is electrical, could the movement of the clutch cable in the headset be pushing the kill wire against the headset or where it passes through the top of the steering column and there might be a break or wear in the wire coating causing a short ? Does this occur with the handlebars turned hard to either side ? Does it happen if you disconnect the kill wire at the junction box or the coil or the CDI ?
As Christopher and I asked, is it like touching the kill button momentarily? Will the momentum of the motor let it fire back up when you let off on the lever before it stops turning?
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Thu Oct 15, 2020 4:30 am quote
If you increase the RPM to say 3000 rpm and pull in the clutch what happens? If something is binding a bit that should over come it.
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Sun Oct 18, 2020 6:08 pm quote
pulled it apart
So I spent some time this weekend pulling the gas tank out as well as head lamp and speedo. I was too the point where I need proof that there wasn't any issues with the wiring. I basically pulled the loom slack as far up into the head space as I could to check if there was any wear in the protective sheathing around the wires. I wanted to get past the the area where the headset and frame(neck?) rotated to see if that is where something would have cut into the wiring. I saw and felt nothing... With it apart and feeding gas down the gas line I started it up and there was no immediate issue when squeezing the clutch handle. I got past the point of where it usually died. But with the clutch handle in the engine did die after a few seconds. So I turned up the throttle slightly and then there was no issue, it idled which seemed fast to me but it didn't die.
So I guess we are seeing weird issues where it acted like electrical issues but perhaps the idle is set too low to when using the clutch it was putting enough pressure to cause it to stall? Maybe i moved the loom enough to change where the cable was causing some strange short? Could be one or all of these at the same time. I will finish putting it back together and see if I can drive it without stalling.
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Mon Oct 26, 2020 6:20 pm quote
Jack221 wrote:
There is always movement in the main crank bearing. Pulling the clutch moves the flywheel. Your pickup will be mounted too low. It will need to be spaced away from the backplate. How thick the spacer will be is another story.
When you pull the clutch lever, how far does the flywheel move? What Jack's describing is a known issue, although not always seen in your situation.
Moto64 wrote:
Does it happen if you disconnect the kill wire at the junction box or the coil or the CDI ?
Does it?
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