CVT Help Please!!

[atelhaddad]

Hi, I've recently purchased a scooter in Egypt

It's Called Znen Roar, the one that's offered in Canada in 250CC water-Cooled variant, here we get the smaller 150CC

I've had a lot of problems with the CVT system but to cut it short, it keeps cutting belts for no apparent reason, I've changed the Variator, Rear Clutch assembly and belt to make sure nothing is going wrong anymore.

A while after that the scooter started jerking on take-offs and low RPMs, I removed the CVT cover to inspect the system, and I've realized tear and wear marks on the outer side of the belt (the belt rubs against the CVT Cover)

So now I don't know what to do, I want to reach the optimum setup for better durability, If anyone can help me decide the following I'd really appreciate it:

Here's the info about the scooter

GY6 157QMJ (150cc)
12 inch wheels
Rear Brakes: Disks
Stock Belt Size: 835 20 30

Here's what I need to know:

1- Safest Variator diameter: ... mm

2- Safest Roller Weights Dimensions: Diameter x Length x Weight. Please bear in mind that I don't care about fastest top speed or quickest acceleration

3- Safest Belt Length: (I've read that 11" wheels or bigger should use 842's, need help on that too"

4- I also need to know whether it's safest to use rollers, or sliders, or a combo of both? And recommended weights

Thanks a lot everyone

[Blueboy5000]

The 842-20-30 is indeed your proper belt. Use a high quality belt like a Gates or a Bando.

Make sure your kickstart assembly is installed correctly (or removed) as that is the most common source of "rubbing" on a belt in a 157 CVT.

[teddy554]

i would grind the spot down were the belt is making contact and i would use either slider or roller and nor mix just imo but slider last longer and have a slight advantage over rollers and 18x14 in size i believe this are stock numbers
18x14 Roller Weights (13 gram)
Drive Face Inner Diameter (peak to peak): 13.6mm
Drive Face Inner Diameter (valley to valley): 15.2mm
Outer Diameter (drive face): 115mm
Number of Splines: 19

[rockynv]

Start with the filter on the CVT case. If it is clogged with sand then you are going to go through belts like there is no tomorrow even if everything else in there is new. If cleaning the filter does not help than move on to the kickstart which is also a known villan here. Remove it and if the problem goes away you will know for sure that is what the problem is.

How many miles/km on the bike?

[atelhaddad]

Thanks everyone,

The kickstarter's bush (No.14) is kind of broken, but I thought it wouldn't be a
problem since it's supported by the front bush on the CVT case (No.15)

But anyway, I am going to get the new parts and test them out and let you guys know .. appreciate the help, everyone

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[50cc]

My old engine was like that and I was snapping belts every 1500 km or so. I changed the bendix and the CVT cover and never had the problem again.

[50cc]

Also, check if you have a copper washer on the crank (between variator and crank case) and remove it if so. Qingqi engines do have the washer and they tend to snap belts frequently.

[Deleted]

They are a bit costly but this is the reason why I insist on the use of Aramid fiber Gates Premium kevlar belts for my 150cc, the part number is PL30708

If ordering two makes the shipping cost less, keep one in the glove box as a spare.

[atelhaddad]

Okay, so I removed the kickstarter and installed a new variator, took it out for a long 50 Km test run.

Went back home and removed the CVT cover and I realized something quite weird .. The belt is fine but the variator is snug at the tightest gap "belt at highest point. I tried to feel the rear plate with my hands and I realized that the roller weights are all misplaced, they've gone out of their compartments.

I removed the whole assembly, placed the rollers properly back in place, and reinstalled it without closing the CVT cover ... Revved it for a couple of times and rechecked, the rollers were out again -__-

To be frank, I am using a very cheap variator (the best I can get in Egypt) which is sold here for 70 Egyptian pounds, that's about 11$ ;D ... And I can't find anything better.

I am planning on ordering a proper transmission kit (I'm open for any suggestion) but my only fear is that it might not be a problem with the variator in the first place.

So can anyone confirm if it can't be anything other than the variator? And if it is, please recommend a decent kit, not necessarily a "racing" kit ... Anything within the 200$ range will be feasible.

Thanks again everyone

[atelhaddad]

Sorry rockynv, just saw your question,

The bike has 2700Km on it ... about 1685 miles

[dyoung1167]

something is not allowing the variator to stay in one figurative piece. make sure the rear drive face has free movement back and forth and the back plate slides freely on it's guides within the rear drive plate. for instance, a notch in a guide arm. also, it is very easy to have a weight get sideways during installation even if it looks closed. just one crooked weight will cause the rest to get out of wack during first rev.

[rockynv]

Does the ramp plate seat tighly against the back of the variator? You may be orienting it incorrectly however I would not expect you would be able to put the nut on the drive shaft and lock it down if you did. How does it compare to the original one? You may have been given a mismatched setup.

Personally I was very impressed with the Hoca Teflon Variator with modified rampiing. Made a big difference in how my old 150cc Znen Vintage bike pulled out with no other changes. $49 from PartsForScooters who is local to me. I can order and pay over the phone and then do a customer pickup.

[jazzman]

What size Weights are in there they could be the wrong size weights(meaning the actual size of them) most 150 CY6 Variators take 18x14 size weights. Check the weights in the Variator RAMPS and they should fit really good with not to much play from side to side.

If you can take a picture of the variator with the weights in it that would help. I am betting the weights are the wrong size TO SMALL so they pop out and get sideways.

[Deleted]

It's starting to make more sense now...

There exist on the variator, in addition to the rollers / slilders, three keys.
They look like little U-shaped plastic devices.
Usually black but I've seen them in other colors as well.

I would imagine if you're missing them, the variator would fail to keep the rollers in place.

[Blueboy5000]

I'd swap out the entire variator with a new stock one. Variators are not very durable, and could be damaged if the rollers have become displaced while running.

You need 18x14mm sized weights/rollers, it sounds like you have the wrong/damaged rollers in your variator.

I have used this one,( which is currently on the bike pictured in as my avatar) from this site and it is a good variator.;

www.monsterscooterparts.com/variator-assembly-150cc-and-125cc-gy6-qmi152-157-qmj152-157-engine.html

[atelhaddad]

Here's a piv of the variator ... Looks pretty normal to me ..



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[Blueboy5000]

I can see damage and lots of belt dust.

No that does not look normal. Can you post a pick of the driveface plate?

[rockynv]

It could be just be the shadows however the rollers look too short. Are they really shiney metal or is that just the picture making them look that way. They should be self lubricating nylon or polymer with a metal weight in the center. Does not look right when you enlarge it and try to look close.

[atelhaddad]

I'm done with disassembling and reassembling ... I've ordered the NCY Super transmission kit, their products look pretty high quality, added Dr. Pulley sliding weights (11 grams) and will couple those with the Gates premium 842 belt ... The kit comes with a 1000RPM Compression spring ... If this doesn't solve my problems I'm going to kill my self ... Hopefully I won't have to