SHUDDERING AT SLOW SPEEDS By Alleyoop (Read 3,398 times)

[damorg5623]

Greetings, I am having the same problem with my 2011 MC54-250cc. Motor Scooter. It shudders terribly when starting off from a dead stop. Goldenvale sent me a new variator, as my scooter is still under warranty. I just got it in July 2012. I haven't had the chance to install it yet, I logged on here to find out any, and all the information I could before attempting this.
I noticed when I removed the variator/clutch housing cover, that my variator fan also has the small surface cracks in it.
At the time, I didn't think that they were severe enough to warrant any cause for concern, however now I'm wondering if these tiny cracks might be a problem later on down the road.
I am hoping that I can persuade the mechanic, who I have spoken to at Goldenvale, to send me a new variator fan, once I tell him that there are others who have the same problem with their variator fans.

[james03x]

can you upload some pictures then i would be more helpful, but your scooter has much low speed even low than 200cc i think you should contact with some mechanic in your own town.

[damorg5623]

I replaced the NEW variator that I received from Goldenvale yesterday, 09/09/2012. I took it out for a test ride and my Scooter is still Shuddering when starting off. I called Goldenvale today, 09/10/2012 to let them know that the shuddering problem was NOT solved by replacing the variator. I spoke to someone there named Chris, this time and he told me that he thought that the problem might be...
1) A BAD spark plug, or gap.
2) A BAD CDI
3) Bad Timing (he said that he thought that the timing was most likely fine)

Does anyone have any thoughts on this?
I am at my witts end with this scooter.
Personally, I don't see how those things, the spark plug, or CDI. could be causing the terrible shuddering that I am experiencing.
Am I wrong?
Could it be one of those things?
It took me 4 years to save up enough money to buy this MC-54-250 scooter, I haven't even had it for 2 months. I have yet to enjoy a single ride on this thing. I don't even have 500 miles on it yet. It haunts my every thought. I just can't seem to figure it out. What could be causing this shuddering problem.
Please... would someone please point me in the right direction so that I can solve this shuddering problem, and get on with my life.

[Alleyoop]

No those things would not cause the shuddering, those things cause the motor to not run right missing and or dieing.
If it is shuddering when you ease on the throttle it is because the CLUTCH PADS are slipping on the Bell. The 250s like to Idle around 2000 rpms and the it should start to move when your RPMS are around 2500 or so RPMS. If you have a few miles on it Check the Clutch Pads they are most likely Glazed and causeing the slipping. I am sure once you get it moving after the shuddering it is ok.
Alleyoop

[damorg5623]

That is correct, once I get moving the scooter runs great.
It's getting past the initial shuddering that is killing me.
I have decide, after reading thru all 25 pages of this forum, anything having to do with "shuddering", to remove the clutch bell and rough up the clutch pads a bit. I sure hope that this makes a difference.
Even if I had to do this every couple of months... it's easy enough to do.
Thanks a bunch for the feed back... Alleyoop

[Alleyoop]

It is a very common problem especially with the heavier scoots. I am sure that is causeing your shuddering taking off. Once the RPMS get and turn the Clutch faster more centrifigual force is created to really put more clutch pad pressure on the bell without slipping. Let us know if scraping the glaze off did the trick.
Alleyoop

[damorg5623]

Good Afternoon Alleyoop,
I roughed up the clutch pads this morning as you suggested, using 220 sand paper. I also took some emory cloth to the bell housing. I was so sure that this was finally going to fix my shuddering problem, that I couldn't wait to test drive it.
Well, I was wrong.
At first it seemed as if it was going to be OK, when I started off, everything seemed to engaged perfectly.
I rode for about 10 minutes, stopping 4 or 5 times at red lights etc...
Each time I started off it was very smooooooth. After about 10 minutes though it styarted to shudder again, just like it did before.
It has always been OK for the first 3 or 4 miles, then it always starts the shuddering after that.
Like I said yesterday in my post, I read thru all 25 pages of posts, everything that sounded like a shuddering problem and it looks to me like there are at least 3, maybe 4 people who have experienced this same problem.

So far I've replaced the variator with one that Goldenvale sent to me, with NO difference.
I would like to say here that I've looked at several You Tube videos which were about servicing the variator.
In everyone of them, they say to clean out all of the gunk, and only lube the three rubber grommets that help the ramp slide in and out.
Both my original variator and the one that Goldenvale sent to me had a good bit of grease inside of them. Because of the You Tube videos, I cleaned out all of the grease, hopibng that this would help with the shuddering problem... It did not.
I also have roughed up the clutch pads (did that this morning) with no change in the shuddering.
I'm wondering if the main clutch spring is too weak, or too strong maybe?
What about the other springs which are in the drive clutch, could there be something wrong there?
I have NO idea where to go from here.
I have worked on my own scooter ever since I first purchased a 50 cc. back in 2003
I haven't ever had to get this deep into the workings of a scooter.
Prior to this problem the worst that I ever had to do was replace the starter motor on my 2nd. scooter a Roketa Bali MC-13-150cc. My point is this... I'm not total incompetent, i do know a little bit about these scooters.
This has been a really good learning opportunity for me, however enough is enough.
What the heck is the problem here?
Why won't this scooter take off smoothly everytime I start off?
Just like it does the first thing in the morning, when I leave for work?
It starts off so nice and smooth, and then after several minutes and a few miles, the shuddering starts, and doesn't stop until I do.
I mean until it reaches 10 mph.
Get going faster then 10 mph, then it's perfect.
I'm unable to ride slower then 10 mph after it gets warmed up, without the darn thing shaking like crazy.
Please Alleyoop... HELP ME ! Please Somebody, Anybody Help Me?
What the hecks the problem with this scooter?
What have the other prople who have had this same problem done to fix it?
If you don't want to have to type it all out, call me...
Dan
443-653-1674

[Alleyoop]

Do you know what the rpms are when you are going around 10mph or so that it starts to SHUDDER?

If the Clucth springs where changed to STRONGER then I could see it acting up on you at low rpms. The other thing is maybe once it gets hot the PAD ARMS are sticking on the Swivel Stud.
You take the Clutch off and Put a little bit of oil where the PAD ARMS go in and out against the metal holders. You can work the pads in and out with a Screwdriver HERE IS A PICTURE of how to work the PAD ARMS in and OUT when you put a little oil where it hits the metal holder.
Alleyoop
See where I put the screwdriver in and just work the ARMS in and out after you put a little oil on the Studs that it swings in and out on.

[mtsing]

I recently purchased a Chinese MC-54-250 and experienced similar problems with starting up and noises, rattles, and now I cannot start the engine. This is not even registered yet, less than 50 miles on the scooter! I found the idle speed screw by looking at the carberator and turning the throttle - I also set the idle speed to 18k to 20k RPM. Thought that I had everything fixed until I took for a test ride and the engine stalled. Now it will not start - I am wondering if the idle speed screw and the fuel mixture screw (mentioned in a previous message) are the same thing. Is there a seperate fuel ratio screw? if yes, can someone help me out where I find that? -- thanks -- and I too am new to the site and to scooters.

[Alleyoop]

Hi Mtsing,
Yes there are TWO adjustments ONE is the FUEL RATIO MIXTURE SCREW and the other is the IDLE SPEED SCREW to raise or lower your IDLE.
Here is probably what your carb looks like and I have labled the parts on it.
Alleyoop

[damorg5623]

Hey Alleyoop,
Thanks for the feed back.
It looks to me like in order to do what you are suggesting, oiling the PAD ARMS, I will need to remove the entire clutch housing and open it up.
Would this require me to remove the large nut on the rear of the clutch housing?
Because while I do have an electric impact wrench, and I have watched several videos of people doing this, I DO NOT have a socket that BIG.
If I were really, really careful not to get ANY oil on the PADS or ANY excess oil that could possibly splash into the Clutch Bell do you think that I could oil these PAD ARMS without taking the clutch apart all the way?
If so, I will try to do this tomorrow morning.
Also, I was wondering...
I noticed that when I replaced the variator fan, it seems top only go halfway up the splines.
It almost seemed to me that the Boss Pin was possibly too long.
Because of the way that the variator fan is positioned on the drive shaft, I noticed that it makes it very tricky to get the nut on the drove shaft without pinching the drove belt.
Do you know what I am trying to say?
If you do, then everything is normal.
It just seemed to me that the variator fan should be flush with the ends of the splines on the drive shaft, and that the splines should not be somewhere in the middle of the variator fan hub.
Does this make any sense at all?

Also, Please let me know if you think that I should try to oil the pad arms without opening up the clutch housing entirely.
Thanks !

Dan

[damorg5623]

Hey Mtsing,
I'm not trying to be smart or anything, but have you checked to make sure that you didn't accidently hit the kill switch? Your scooter will turn over and over and over, but never start if it is in the kill postion.
I've accidently done this a million times, and when my scooter won't start for whatever reson, the kill switch is the very first thing that I check.
Good Luck!

[Alleyoop]

No you do not have to take the Clutch apart Just take the bell off and you will be able to get at the Pads. But if you need to take it all apart the way i do it is I have a big adjustable wrench and I lay the clutch down Then I put one KNEE on one side of the Clutch and One Hand opposite my Knee then I LEAN FORWARD compressing the Spring and use the Wrench to loosen the Nut and then unscrew it with my hand. Then you let up easy and it is off. I do the same thing when putting it back together. So All I use is my Knee and Hand and a adjustable wrench or you could use big Pliers that will go around the big nut.


Now to get the Fan PLATE on good What I do is SQUEEZE the OUTER CLUTCH PULLEY OUT TOWARDS YOU and with your FINGERS PUSH THE BELT DOWN INTO THE CLUTCH PULLEYS. Then I put the FAN PLATE ON and washer and start the NUT by hand and leave it LOOSE. Then I SQUEEZE the Belt together around the middle of the VARIATOR and CLUTCH and that will MOVE THE BELT UP the VARIATOR so you can get the FAN PLATE ON GOOD on the SPLINES. Then I TIGHTEN the nut by hand and try to rotate the FAN PLATE to make sure it is on the SPLINE then I get my IMPACT WRENCH and give it 3 1 Second Bursts tightening the nut. I then start the motor give it a couple of revs and then give it another 1 Second burst on the Variator nut for good measure.
The Variator FAN PLATE is Just about even with the Splines I put a washer to make sure the NUT is not Hitting the Splines and IS Tighting the Fan Plate.
Alleyoop

[damorg5623]

OK, I'll let you know how everything turns out tomorrow. Hopefully, this will do the trick.
Thanks again for all of your feedback and help.
Dan

[damorg5623]

Well, I took the CVT cover off again this morning. I removed the clutch bell, and the drive clutch assembly. I very carefully oiled the pivot points with WD40, worked the clutch pads in and out, using a scrwew driver just as you suggested. After putting everything back together, I took my scooter for a test drive. When I took off it did so very smoooothly. That's not so unusual because the very first time that I start off every morning it has always taken off smoothly. The true test is after about 10 minutes and 3-4 miles. Well, I was just about ready to call this fix a success, when I headed home and wouldn't you know it, the shuddering suddenly started up again. Not nearly as bad as before, but not as smoothly as it should be either. I believe that you/we are on the right track with this lubrication of the pivot points of the clutch pads.
Now I'm wondering if a better oil should have been used, or maybe even some grease?
I would have to disassemble the entire clutch in order to apply the grease correctly to the pivot points, but it would surely be worth ALL that if it would solve my problem, once and for all.
What do you think Alley?
Is wd40 a poor lubricant?
Also, I wanted to mention...
After I put the clutch bell back on and tightened up the nut, I ran the scooter for awhile, just watching everything do it's thing. I would rev. it up every once in awhile just for the hell of it.
Anyway, I noticed that the clutch bell gets pretty hot after awhile. Is this normal?
There isn't any blue or purple discoloration showing, it just seems to me to get awefully hot to the touch.
I hope that this is normal.
I will try tomorrow to lube it up a lot better with a better, thicker oil, and then if necessary I'll try the grease.
Is that a good game plan Alleyoop?