cvt and rpm variation

[br4inl3ss]

thanks for your reply.
i used this method in the early day of owning the scooter and learning the basic of cvt. but then someone else saaid to not go this way. nothing bad, according to him, just not the best way.
today tis what i did tho. trying to see if there is any change for my situation.
absolutly nothing. same tension, same place on front and rear pulley and same everything.

i know this site. its actually one of the biggest. sadly like all other in the usa / or anywhere not in canada or chine, its total scam. sometime its the shiooper that scam, sometime its the delivery. weither it is, it end up bein a huge scam, or rippoff if you prefer.

the mroe i think about it, the more i think that i fixed 90% of my overheating issue resurfacing the fixed pulley, but then the crank seal started to leak then caused slippage. then cause the belt to slip, crack, glaze like crazy, and put a brown'ish mark on the variator ( not dark as the belt but more like heavy heat ? ). the crank seal leakage comed from the pits on the shaft, but how on earth could this happen..........

[kosmos]

brown grease, hmmm. That driven rear (clutch) pulley has some grease that looks brown in it when it gets old. maybe it is spreading around by your belt. Might need to check the seals on your driven pulley. it can lock up when the seals break and stay open causing the belt to break.
if you've got any issues with the cvt it can overheat; something not right. Or if you saw oil coming out of the crank shaft seal then thats the source of your oily cvt. But that is usually black from what I can remember.
If you can change your contra spring you can take the clutch pads off the clutch pulley and check if it slides back and forth good and look down in it when you open them up and see if the seals in place or cracked or anything. maybe regrease it while its off. but if the seals are busted, i dont know where you can get them and you'd need another one. probably its yamaha, measure the length and if your belts 28 angle then one that uses that pulley. it might match a yamaha like a jog.

[kosmos]

May 16, 2023 5:42:03 GMT -5 aeroxbud said:

Yeah the Minarelli motors are easy to get a drill to line up with. The Piaggio ones are the same nightmare. So small you can't get a drill bit straight.

<edit> oops seems like I quoted the wrong person, makes more sense now.  But anyway the questions still work
to me, that seal looks  like,  I don't know anything about your motor it looks like a yamaha with that crank arm but to me the seal, looks like its sticking out a bit too far.  If its not like other yamaha's you could knock it in there a little but,  brown grease doesn't seem like something from out of the crankcase.  might be something slopping around in from your cvt case, and the only place I know of is the rear driven (clutch) pulleys grease.  overheating tho as you talked about would be a sign of an air leak in the motor too as well.  Do you have overheating issues with the motor?  does it cut out does it run well?






Heres a couple pictures of my cvt, how the belt sits in it with stock mostly everything, belt, driven pulley, front drive half, and aftermarket variator is all.  Why I think yours is too tight is the belt sits lower down than that little rounded curve; the lip, like on mine.  But this is an example of how they sit.  I was tightening my belt with my hand too seems I have a little bit of a worn belt.

[aeroxbud]

May 18, 2023 4:00:13 GMT -5 kosmos said:

May 16, 2023 5:42:03 GMT -5 aeroxbud said:

Yeah the Minarelli motors are easy to get a drill to line up with. The Piaggio ones are the same nightmare. So small you can't get a drill bit straight.

<edit> oops seems like I quoted the wrong person, makes more sense now.  But anyway the questions still work
to me, that seal looks  like,  I don't know anything about your motor it looks like a yamaha with that crank arm but to me the seal, looks like its sticking out a bit too far.  If its not like other yamaha's you could knock it in there a little but,  brown grease doesn't seem like something from out of the crankcase.  might be something slopping around in from your cvt case, and the only place I know of is the rear driven (clutch) pulleys grease.  overheating tho as you talked about would be a sign of an air leak in the motor too as well.  Do you have overheating issues with the motor?  does it cut out does it run well?






Heres a couple pictures of my cvt, how the belt sits in it with stock mostly everything, belt, driven pulley, front drive half, and aftermarket variator is all.  Why I think yours is too tight is the belt sits lower down than that little rounded curve; the lip, like on mine.  But this is an example of how they sit.  I was tightening my belt with my hand too seems I have a little bit of a worn belt.

It's a piaggio, and it was leaking. That was a week after I cleaned it .

[br4inl3ss]

its not brown grease. its brown like way too much slipping and it overheated.

sad its reassembled and i forgot to take photo.
looked on google images with "metal friction overheat" and it came with the perfect representation.


but it was running so much better last ride before it start to slip like no tomorrow and the belt smell come back, i'm prety sure the seal leaked and oil went on the variator or belt. when i replaced the seal it didnt seem burnt at all. just a but chipped where it contact the shaft ( we could see it with good light and a usb microscope, before i even try to remove it ).
it didnt seem enought to cause such a leak but anyway. still i dont get it. what in the world would scratch and pit the shaft like that...

anyway it doesnt seems to leak for now. ill see when i ride it.

[br4inl3ss]

May 18, 2023 4:00:13 GMT -5 kosmos said:

May 16, 2023 5:42:03 GMT -5 aeroxbud said:

Yeah the Minarelli motors are easy to get a drill to line up with. The Piaggio ones are the same nightmare. So small you can't get a drill bit straight.

<edit> oops seems like I quoted the wrong person, makes more sense now.  But anyway the questions still work
to me, that seal looks  like,  I don't know anything about your motor it looks like a yamaha with that crank arm but to me the seal, looks like its sticking out a bit too far.  If its not like other yamaha's you could knock it in there a little but,  brown grease doesn't seem like something from out of the crankcase.  might be something slopping around in from your cvt case, and the only place I know of is the rear driven (clutch) pulleys grease.  overheating tho as you talked about would be a sign of an air leak in the motor too as well.  Do you have overheating issues with the motor?  does it cut out does it run well?






Heres a couple pictures of my cvt, how the belt sits in it with stock mostly everything, belt, driven pulley, front drive half, and aftermarket variator is all.  Why I think yours is too tight is the belt sits lower down than that little rounded curve; the lip, like on mine.  But this is an example of how they sit.  I was tightening my belt with my hand too seems I have a little bit of a worn belt.

yeah thats how people get them. thing is from factory NO chinese scooter comes like that. and ive seen many STOCK bw's/zuma and they're far from that too ( its not how they should be, its how they are as a restriction. longer belt = very good mod as a satrting point ).

people with 139qmb can get a longer belt to fix this issue ( original is 669-18-30 ) like 671-18-30 or something. but i have the long case, 13 inch wheel, with 729-17.7-30 belt. no longer belt can fit there. there is some 732 belt, but they're 20mm wide. and if i read correctly, you can put a wider or longer belt, but not a longer AND wider belt. anyway i tried to ask many times, no one answered with longer belt from 729. only the damn widespread short case with 669 belt. 

[kosmos]

May 18, 2023 11:26:45 GMT -5 br4inl3ss said:

May 18, 2023 4:00:13 GMT -5 kosmos said:

<edit> oops seems like I quoted the wrong person, makes more sense now.  But anyway the questions still work
to me, that seal looks  like,  I don't know anything about your motor it looks like a yamaha with that crank arm but to me the seal, looks like its sticking out a bit too far.  If its not like other yamaha's you could knock it in there a little but,  brown grease doesn't seem like something from out of the crankcase.  might be something slopping around in from your cvt case, and the only place I know of is the rear driven (clutch) pulleys grease.  overheating tho as you talked about would be a sign of an air leak in the motor too as well.  Do you have overheating issues with the motor?  does it cut out does it run well?






Heres a couple pictures of my cvt, how the belt sits in it with stock mostly everything, belt, driven pulley, front drive half, and aftermarket variator is all.  Why I think yours is too tight is the belt sits lower down than that little rounded curve; the lip, like on mine.  But this is an example of how they sit.  I was tightening my belt with my hand too seems I have a little bit of a worn belt.

yeah thats how people get them. thing is from factory NO chinese scooter comes like that. and ive seen many STOCK bw's/zuma and they're far from that too ( its not how they should be, its how they are as a restriction. longer belt = very good mod as a satrting point ).

people with 139qmb can get a longer belt to fix this issue ( original is 669-18-30 ) like 671-18-30 or something. but i have the long case, 13 inch wheel, with 729-17.7-30 belt. no longer belt can fit there. there is some 732 belt, but they're 20mm wide. and if i read correctly, you can put a wider or longer belt, but not a longer AND wider belt. anyway i tried to ask many times, no one answered with longer belt from 729. only the damn widespread short case with 669 belt. 

Here's 2 from that site I linked 738-18-30 and 732-18.5-28 so they're out there.  Theres only those 3 dimensions that can cause your belt to be too tight. 

My way I check it is if its not a stock part then I put it on by taking the variator side nut off and the front half pulley and slip the belt around the back and then if the belt doesn't go over the drive boss on the front Drive side without being any more than 'fits like a glove' tight, then it is to tight.  Some chinese bikes use odd sized belts.  I can explain this but its a bunch of engineering stuff that the bike makers have made up.  

but the only places the bike has to give when the belt is too tight is the only play in it it can have, and thats against each half of each pulley its riding on, putting pressure on only one half of the pulley.  and the only play is the ramp plate between the variator basket and the seals inside the driven clutch pulley where the 2 pulley halves meet.  

[br4inl3ss]

UPDATE:
received new variator kit.
while there i put the last new belt on. problem, this belt is shorter ( stamped 729-17.7-30 right on it ). seen that alot lately, same belt of different actual size ( remember the MOGO belts i talked way earlier in another thread ? )
older one ( yellow ) measure exactly 729mm, new one ( green ) measure 719mm. ( i might be 1mm off )
i'm done with cheap belt. its SAD because Glixal belt seemed to not shred prematurly.
and different batch now...



only option was to try the 1PZ ( kevlar premium ) belt on amazon ( since i'm a prime member, and amazon doesnt scam huge time on shipping ). 26$ CAD instead of 15, maybe there is a difference in quality ( especially since this one is a premium one made with kevlar ). returned the Glixal belt to amazon and bought the 1PZ.

put back the old belt ( WTF it helt the run ) and went for a long test ride. 6.5g rollers that come with the variator are way too heavy, so i put back the 2000 rpm contra spring on ( red ), and ill test like that. else ill try again with heavier rollers.

it was such a good ride with blue 1000 rpm spring and 6.5g roller wow. didnt feel this since a long time. i feel the clutch grabbing actually. but after maybe 20 min, the takeoff rpm started to hit 7200 again ( its not too high, in fact its too low, but when cold it would not go past 6500 unless i go downhill ). then lower to 5700-6300 rpm cruising.
thats why i'm trying back the 2000 rpm contra spring, because the other day before the crank seal oil up the cvt, it was sooooooo gud !.

oh by the way, crank seal is fixed... for now... 2-3 ride and not a single micro sign of oil there. pits in the shaft doesnt seems to affect sealing .
while changing the contra spring, i noticed much play in the pulley assembly. liek ALOT ! we can see the torque driver wiggle over the fixed pulley ( driven ? ). even tho the seals are done, no grease comming out.



i guess ill be on for a new pulley setup, once again but not right now. this horror of a scooter keep emptying my wallet. god if i could, oh lord, i'd liek to buy that AWESOME SSP-G transmission kit. damn its 250$ CAD + tx. but i guess idd be okey for at least a season LOL. look like ssp-g is very high quality on par with naraku malossi polini and what not. yeah ima keep dreaming of it. my dreams keep swappign from one to the other : dreaming of a WORKING scooter & dreaming os a quality transmission kit

the cvt seemed a little bit cooler ( because the belt didnt snap yet and its a good cvt temperature gauge for me at this point LOL ) but engine hit 326 F. was running strong and everything. what is weird is that i made a engine cover seal from rubber hose since mine was done & gone and cannot get one alone at a decent price ( 60$+ for a damn small rubber that is worth like 7 at max ? no thanks ). it means better cooling increase temperature, but logic say otherwise

anyway. ill keep you updated on everything, and keep reading.

EDIT: belt snapped. and variator fan almost melted again.

[aeroxbud]

That rear pulley should be a tight fit. 😞
The problem with buying cheap belts is a lot are knock off of the real thing. That's probably why one is longer and the print is different.

[br4inl3ss]

it is a tight fit when i use the 2000 rpm contra spring.
very hard to install a belt with this spring.
but it looks like it make things worse.....
or its just that the belt was already on its last minute...
i took a ride with it and 1000 rpm spring, fine. took a smaller ride with the 2000 rpm spring, belt snapped.

pretty sure it was the belt this time... even with 2000 rpm i still had hide difference in takeoff rpm and cruise rpm. usually i had this happen only with 1000 rpm spring.

i had no smell at all for the ride but 5 minute before it snap. with blue spring, it usually smell a bit ( sometime hard to notice it, nose on the cvt ) from the moment it reach a certain temp.

i just hope cvt overheat is gone with new variator and it was just my old belt ( glazed and cracked, de-glazed in hope to save it while i get the 1PZ premium belt ). i hope its actually a quality belt and of the proper size. i dont ask it to be on par with japan made bando or gates or naraku or whatever, just better than non premium cheap belt.

i went back home on my good ole unbreakable peice of alien spaceship ultra quality Dongil Superstar belt. sad its over-used ( 15mm now instead of 17.5 ).

[aeroxbud]

It should be a tight push fit without any spring fitted. Something is worn. Perhaps the seals.

[br4inl3ss]

May 20, 2023 12:31:28 GMT -5 aeroxbud said:

It should be a tight push fit without any spring fitted. Something is worn. Perhaps the seals.

wait. what do you mean, tight fit without any spring fitted
also, how do YOU check belt alignment ?
i put the phone on the ground and filmed with front camera aiming at the belt.
it seems very straight. the only thing i see is that the front move out a bit before the rear follow. so at this moment its not straight. but this is very fast and it fix istelf right after. this is with 2000 rpm spring.
can a too stiff spring cause issue like mine ? all i can get from internet is that its not harmfull just a waste ( buying stiffer spring but its not needed )

if i understand cvt correctly this is normal since the variator is the DRIVER pulley and the "clutch" is the DRIVEN pulley. 
maybe YOU have a better way of checking it ?

ill take another video of it if you want.

EDIT : here is a video fresh from today. 




EDIT 2 : 
i just found out that most of the scooter of this size have 112mm clutch & clutch bell. mine has the 107... also, ive seen many model of big scooter, a Keeway to name one, that has the same pulley size as mine ( aprox 118mm ) but the big 112mm clutch and clutch bell.

so i'm pretty sure thats my whole issue there... slippy takeoff, constantly overheating, start to slip to an extreme level when hot, clutch shoes glazing in no time ( sanded them and they were glazed after a 35 minute ride ), constantly snappign belts, and so on.
what do you think about that ?
it would also explaine why i have the same problem with the sock AND malossi clutch of the Vino on mine but its extremly snappy on the vino. wrong clutch and clutch bell...

also most heat seems to come from the rear but thats kinda very hard to confirm...

i think im up to find a cheap 112mm clutch & clutch bell to try.

[kosmos]

it doesn't need to be super tight. tight is relative here. My opinion is it should be 'like a glove' tight. and thats when you put the belt over the rear pulley, spring installed to hold the 2 halves together, and then over the front pulley with the variator and drive boss on; before you put the front half of the drive pulley on. if its tighter than glove tight trying to slip the belt over the drive boss, thats too tight. a little bit of looseness is better than too tight. Too tight can burn the belt up too just trying to pull it and having more torque because of the less length. its the length, angle and width of your belt that determines how it fits, and thats part of how the CVT works.
I'll say it again, my opinion and I've had a lot of experience with a chinese bike cvt, was no more than 'like a glove' tight when you put the belt on.
Thats how you should check to determine tightness anyway

[br4inl3ss]

UPDATE:
received the NCY rear pulley assy i borrowed money for.
mine was completly dead once again ( cheap Glixal ).

brand new belt ( 1PZ premium kevlar ) so i know for sure all is new.
also received a Naraku belt after waitign it for 2 month, but i dont want to snap it just yet
only the variator is the same.

still have one of the problems i had : first start when cold it all go fine. but when reaching a decent temperature ( almost operating temp but not yet ) then it start to rev higher at takeoff than cruise.
from 15 to 30 km/h it rev to 7300 ( i know its still low not at peak power ) then slowly go down to 6200-6400 depending on wind or speed ( usually hit 65 with small wind, 70 with no wind at all ).

it this normal ? is this a sign something is wrong ? all the scooter i see either rev stable at all speed or rev lower till 30 km/h or so then rev higher after that. not sure who is right tho.
different opinion on that subject its pretty hard to settle on one and try to get things right.

right now i didnt shim variator yet, wanted to see if the ncy pulley fix overheating issue. right now the wheel spun pretty fast on idle ( not choke ) because the belt is squeezed, so yeah the clutch seems engaged but i dont think it is ( can apply a bit of throttle without it going forward ). it "engage" at around 3400 rpm even with 1500 rpm springs.

this issue is going on since a very long time... even before my Naraku sport variator. that means its alot of different parts. everything changed since then.

what can cause this if its not normal ? is it still safe to reach 8200-8500 rpm for a short time while accelerating ( 72cc bbk with stock Glixal brand new crank ) ?
also what happen if a too stiff contra spring is installed ? i think my red 2000 rpm make belt snapping occure way faster but who know. never wanted to risk a new belt with it and belt was already damaged from overheating.

[kosmos]

I suggest that you do some comparisons and get the right belt. If the new one is tight, the same conclusion will be had.
I think that if you to get the belt over the rear driven pulley and then over the drive boss, you 'have to' pull the rear pulley in and compress the spring to get the belt even over the drive boss, or if the belt doesn't just fit like a glove then the belt is too tight.
Maybe you can measure the distance between the center bolt of the crankshaft over to the center bolt of the rear pulley at the ends, and be consistent, and get a measurement then ask if anybody else would measure theirs and see if you find a match and ask them what belt it is that they use. I would suggest from what you've said so far that the belts are too tight and to be looking at a larger belt.
I had a chinese scooter that used an offsize belt and I broke variator and belts and driven pulleys and never found the right belt until years later when I discovered some other sizes. and this was the problem I had. Ive found heat issues with my new belt and its a bando made in japan for my scooter precisely. its tight, doesnt fit 'like a glove' and I had engine overheating issues. even tried to rejet the carburetor but it just ran worse.

some chinese scooters are made like that, one off. and since you dont know what the original size of your belt was, it may be an e-ton belt, or a jog belt. or some other offsized belts that they make for some odd european bike.

is your bike a 4-stroke?  I thought this was a 2-stroke but I just seen that video you posted on your previous post.  50cc?  theres no telling what it would match.  
shoot, so idk i mean besides measing the center drive shaft to center driven shaft, theres the angle between the 2, one sticking out further than the other.  you will have to be consistent, like both do it in a straight line, making sure to measure center of shaft to center.  someone with your belt could tell you if your measurements is longer and then that would give you, a place to start with what belt size you need.

but to me looking at yoru video, the belt looks a bit deep in the rear pulley at idle.