My scoot is stalling! By styxfan (Read 1,855 times)

[styxfan]

My 2008 Roketa MC-54-250B Linhai Clone continues to have, what we think are carb issues and we can't seem to come up with a solution.
Idle is set around 1500 per the scoot's tach (anything higher and the wheel begins to turn) and until the scoot warms up (after about 10 mins or so, or it has already stalled once) it will stall. During the warm up period, I need to give it a little throttle once and a while so it won't stall, once warmed up, however, it runs fine.
I replaced the O-ring on the enricher to get a better seal, hoping that would help, but it didn't seem to. I had someone hook up a vacuum gage and everything checked OK. Valves are at .004/.006
I even purchased and had installed a replacement carb, but it ran even worse, so I went back to the original one.

Can anyone offer suggestions as to why it's stalling?
Is there possibly an issue with the clutch or variator?
Any questions or suggestions would be very appreciated.

I am getting very frustrated with this thing. My scoot is really starting to lose it's "fun" factor!

[JR]

For sure it's no fun when they don't run right. Just like a lot of people I would think carb also and I'm still thinking that. On this new carb you bought it was apples for apples? There is such a thing as buying a bad one, shouldn't be that way but it happens. Also 1500 is a little low on this scooter, most are set at least at 1700 rpm so this is odd too but tachs can be off.

My first thoughts are vacuum leak or a partially clogged pilot jet. Second thought is a hole in the carb diaphragm.

So let's make a list of things to check;

All hoses to the carb and fuel pump and this intake manifold has two hose ports so if you haven't replaced these hoses now is a good time to go to the local auto parts and get good American made hoses. Also pull the carb manifold and make sure the o-ring is good and it's sealing well. can even use a little red silicone on it if you want. While you have the manifold loose check both brass hose nipples, I had one that I could pull out with my fingers and I put it back in with JB weld. Any vacuum leak causes problems. When you put the carb back in make sure it is in the manifold well and the clamp tight. Also make sure the air filter is clean and clamped on tight to the carb too.

On your carb that you have on now, have you taken it apart and cleaned it? Need to pay attention to the holes in the jets especially the pilot jet, we have how to's in the tech section plus videos in the video tech section. If the pilot jet is partially clogged it effects the idle and when the carb crosses over from the pilot to the main jet it lots of times stalls or stumbles.

When you are cleaning the carb pay close attention to the diaphragm, if it has a pin hole it will also cause this problem.

The new carb, how did it run worse? Sometimes a new carb must be cleaned too, sounds stupid but again it happens.

If you find a bad diaphragm in your old carb you can use the one from the new carb more than likely.

Variator and clutch problems do not result in stalling that I'm aware of?

I'm sure Alley will check this out he's the carb man here and can add anything that I may have missed.

Keep us informed we are here to help.

JR

[alleyoop]

Well the first problem is see is that your wheel is spinning at such low rpms. That means something is NOT right in your CVT. And for it to spin the wheel at such low rpms it puts a load on the motor which will cause stalling. Now if it was idleing at 1800-2000 I am sure it would not stall but your read wheel sounds like it would be spinning pretty fast.

The scoot should not spin the wheel at low rpms usually after 2000 rpms the Clutch pads are thrown out. You either have weak springs or broken springs or the pads are not retracting all the way back from the bell.

So first thing is check your CVT take the cover off and take some pictures of where the belt is sitting in the Variator and Clutch pulley. For the wheel to start spinning means the CLUTCH pads are been thrown out to early or NOT retracting all the way back. So I would take the BELL off and Clutch off and check the Clutch arms for free moveing. You can put a little OIL around the Studs that hold the pads and work the arms out with a screwdriver for free movement.

Here is how to move the pads in and out with a screwdriver:
Alleyoop

[styxfan]

I posted pics on scootdawg. Heres the link: scootdawg.proboards.com/index.cgi?action=display&board=200cc&thread=51539&page=1

[JR]

Looked at your pictures and the last one is a no-no broke fins on the variator outside plate equals off balance and vibration, equals ruined crankshaft bearings equals total over haul of engine.

There are two ways to get the nut off and here is one:

thescooterprofessor.proboards.com/index.cgi?board=gcvt&action=display&thread=236

The other is a impact wrench. You can buy only the outside plate also, replace it and don't run the scooter until you do. You can remove the clutch both ways also for inspection and servicing.

JR

[styxfan]

Yup, that's what happens when a novice messes with something he's not familiar with.
Guess I need to sink additional money into this thing. Oh well, thought it was a good deal when I bought it, but in the long run it appears to be more of a hassle than it's worth.
Live and learn.

So it can't be run at all with any broken fins? Not even a trip or two, to pick up parts or the strap wrench you recommended?

[styxfan]

And where might a purchase the outside variator plate?

[richardthescooter3]

I just took my clutch and variator off Friday, use the impack wrench, it is so easy. Worth the money, the last time I tryed to take variator about 6 months ago, I too broke a fin off.

[styxfan]

Did you run yours with the broken fin?

[richardthescooter3]

I have the mc-54-250b here is what I bought mine.

.partsforchinesescooters.com/2/vatiator_fan_250cc-300cc1682html" rel="nofollow" target="_blank">.partsforchinesescooters.com/2/vatiator_fan_250cc-300cc1682html

[styxfan]

That looks like what's on mine

[richardthescooter3]

styxfan, no I didn't run mine until I replaced the variator fan

[styxfan]

Thanks for the pdf on removing the variator fan w/o an impact wrench. Hopefully I'll be able to loosen the nut with a breaker bar.
That's NOT a reverse thread nut on there is it? Counterclockwise is correct?

[alleyoop]

Yes Counterclockwise to loosen.
Alleyoop

[styxfan]

Thanks for the confirmation. I know it's going to be tough to break the seal, but I didn't want to be trying it in the wrong direction.
I'm first going to try it with a breaker bar and if I can't get it, I do have a friend with an impact that can help me out if I need to.