belt snapping issue found ( 99.9% sure ), 2 reasons.

[br4inl3ss]

hi.
so out of nowhere, i think i found my belt snapping issue.

my kickstarter broke and had to get the welder out.
while inspecting, i noticed a straight scratch on my Naraku belt.
wasted 1h trying to find where the hell it hit the case, ready to grind whatever is in the way....
CANNIOT BE DONE. it doesnt hit the case anywhere.

the belt hit the damn starter bendix !!! ( second reason is belt slipping on the variator, bad cvt tuning i guess since there is ZERO slippeage when using very heavy contra spring and too heavy rollers ( low rpm with such heavy rollers ).

why in the world would the belt hit the bendix, knowing for sure the belt doesnt ride that high on the variator
sure on the kickstand the belt almost fall out, but far from that in normale usage ( about 1/4 of an inch from the outer of the variator ).
just why ? this issue have been running since day one so its not my new cvt setup. i found parts of my old snapped belts around in the garage ( ok i admit it, also 2 in my clothing drawer... adhd usual organisation LUL ). they have the same straight scratch foudn on my naraku belt. and it only happens with the bendix on.

pinted the bendix so i know for sure, and you see its what happen.

yes the blask thing you see is actual belt residu.

with all i have put on that thing trying to get it working as it should, or at least half right, id like to keep the electric starter if possible, seeing how terrible chinese kickstarter is fragile ( can only find chinese parts, no taiwan. and Dio parts arent the same here ). 

[GrumpyUnk]

I remember posting elsewhere about the Bendix need for a bushing in the CVT cover. Did you check for a bushing? If you put the outer end of the Bendix into the CVT side bushing, it will have a little motion, and without the bushing can wobble around a lot more. In your case, it might pay to machine a bushing that has a smaller ID, so the end of the Bendix is not allowed to move around as much.
tom

[br4inl3ss]

yep its the first thing i checked.

i dont get it... now with my actual setup, the belt doesnt hit the bendix anymore.
the only thing is i have low rpm ( ride around 6200 or 6300, by sound.. didnt check rpm gauge was in temp mode ).
i dot hit 7200 or so at full speed ( 63-65 km/h ) with wind in the back in slight downhill, but thats about it.
the belt doesnt hit mac travel on the variator unless tis full throttle on center stand. in real riding, the max it reach is about 5-6mm off the outer edge.

it touch, it doesnt, it touch, it dosent.... nothing to understand lul.
even if the belt was hitting max travel height in variator, it shouldnt hit the bendix.. well not on a fixed setup ( fixed rollers so the variator stay fully closed so the belt is at max height ). it still gets EASY 4mm of clearance. eyeballing.

actual cvt setup is naraku high speed ( "racing" ) variator, 6.5g and 6g rollers, malossi white contra spring ( dio get qmb ), ncy dio rear pulleys and motoforce racing adjustable clutch with crappy glixal red spring.

i still have some belt slipping issue but i cannot fit it for shit. it either slip after takeoff or extramly low rpm at cruise, no matter what setup i try... 200-600 rpm difference btween sliping and cruise.

but whatever for now i can keep the bendix on. RIGHT NOW, not talking about tomorrow, the belt doesnt hit it.

[GrumpyUnk]

If the Bendix is in a fixed position, and you have 4cm(~1.6") of clearance while at rest, either the belt is too long, and flops around shaking and vibrating under load, or the clutch is staying spread apart as the variator closes up, and is allowing too much slack to develop(and thus the slippage?). In THEORY the belt length is fixed, and only the two pulleys vary their adjusted diameter, one getting larger effecively, the other smaller.
I got nuttin' past that.
tom

[br4inl3ss]

thanks Tom.
the belt is a Naraku premium, aka Bando, aka QUALITY belt.
it does measure a but more than 729 ( actually 731 ) but its the better fit i have ever had with any belt, even with the Bando the guy gave me to go home that snapped.
the belt could ride about 2-3mm higher on the pulley at rest but im not chasing top notch setup. im chasing a normally working setup like all those 139qmb around me have.

belt flopping is possible. i think ive seen some on center stand. but only at the top. and i dont see how thats possible, knowing the variator PULL on it at the top so its constantly "stretched", disallowing flop. at the bottom its PUSHED. but no flop down there.

i know its impossible to say what contra spring to use... but bein such a heavy model ( usually 125/150cc but fitted with a 50cc from factory ), with 13 inch wheels, should my Malossi white be too soft ? its listed as 4.2k from malossi but also scootertuning.
www.scootertuning.ca/en/variators-torque-spring/1490005-torque-spring-malossi-white-42l-dio-4260088511737.html
( remember that dio/139qmb share the exact same cvt parts ). its the same listed EVERYWHERE for both anyway.

for belt slipping, yeah i can get rid of it. easy... putting caterpilar roller weights ( expression, duh ). so heavy that it barely accelerate, barely hit 50 km/h, barely reach 5500 rpm. almost fall on the side at takeoff its way too slow.
no matter what spring i try, same shit apply. for exemple with my malossi white spring, to get rid of all slippeage, i have to put 7g rollers. with my glixal PoS 2000 rpm spring ( very stiff... like really ! ) i have to use 9g rollers.
right now with my malossi white spring im running 7g and 6.5g iirc. minor slippeage when hot, but bad acceleration ( hit decent speed tho ) and low rpm cruise ( 5800-6300 ). reach 7200 when accelerating.
and i know its slipping i see it on the belt... and feel.

i tought it could be my horrorific carburetors ( always way too rich and impossible to tune ) causing the low rpm because its constantly flooded ( yup it reach 10:1 AFR, and even more its the max it can show lol ). from time to time, when HE want, i can play with throttle a bit and it will run steady at 11.5 AFR ( rpm is a bit higher too ), but the moment i move throttle or hit a pothole, its back to overly rich... yeah yeah i know i have to fix that... after 7 different chinese carb and a keihin wortk 400$ CAD, im getting a dellorto phbg 19 ds soon. multiple adventage. first ill get actual help tuning it and the float height is actually adjustable without wasting 39458672874567 days on it. second, with such a quality carb if its impossible to tune again, then the problem ( impossible to find ) is elsewhere. in any case, its a huge WIN.
anyway that would explain the low rpm, not the slippeage... or its just not stiff enought mixed with no power from overly rich ?... yeah possible. complicated. its everything at the same time, and basically nothing fix any issue.... only belt snapping seems fixed. but because of minor slippeage, my naraku belt shows sign of heat because the outer layer start to "unglue" itself.

i get some help here for the weirdo carb, but its complicated and not my main language. and whoever i call just refuse to help if its a fucking 4 stroke scooter, imagine when i tell its a chinese 4 stroke... did a test, called 4 shop and said it was a dellorto carb on a 4 stroke zuma, i had instant help. asked my brother to call the same shops for basically the same probleme but with diaphrags carb, oen even closed the call without any word. pathetic scrubs here.....
a shop named "VTT Lachute" took time to listen to what my problem is, he talked to his mechanic, and he said its 100% my carb. i was like ok so a bad carb make the cvt slip ? he said yes absolutly. well i ended the call without any word.
according to him a badly seated carb cover ( holding the spring and the diaphragm ) cause all cvt to slip.
thats the usual help i get lol.

[kosmos]

Jun 21, 2023 14:46:58 GMT -5 br4inl3ss said:

hi.
so out of nowhere, i think i found my belt snapping issue.

my kickstarter broke and had to get the welder out.
while inspecting, i noticed a straight scratch on my Naraku belt.
wasted 1h trying to find where the hell it hit the case, ready to grind whatever is in the way....
CANNIOT BE DONE. it doesnt hit the case anywhere.

the belt hit the damn starter bendix !!! ( second reason is belt slipping on the variator, bad cvt tuning i guess since there is ZERO slippeage when using very heavy contra spring and too heavy rollers ( low rpm with such heavy rollers ).

why in the world would the belt hit the bendix, knowing for sure the belt doesnt ride that high on the variator
sure on the kickstand the belt almost fall out, but far from that in normale usage ( about 1/4 of an inch from the outer of the variator ).
just why ? this issue have been running since day one so its not my new cvt setup. i found parts of my old snapped belts around in the garage ( ok i admit it, also 2 in my clothing drawer... adhd usual organisation LUL ). they have the same straight scratch foudn on my naraku belt. and it only happens with the bendix on.

pinted the bendix so i know for sure, and you see its what happen.

yes the blask thing you see is actual belt residu.

with all i have put on that thing trying to get it working as it should, or at least half right, id like to keep the electric starter if possible, seeing how terrible chinese kickstarter is fragile ( can only find chinese parts, no taiwan. and Dio parts arent the same here ). 

If you don't have that issue anymore why worry about any thing? lol

[br4inl3ss]

Jun 26, 2023 16:53:02 GMT -5 kosmos said:

Jun 21, 2023 14:46:58 GMT -5 br4inl3ss said:

hi.
so out of nowhere, i think i found my belt snapping issue.

my kickstarter broke and had to get the welder out.
while inspecting, i noticed a straight scratch on my Naraku belt.
wasted 1h trying to find where the hell it hit the case, ready to grind whatever is in the way....
CANNIOT BE DONE. it doesnt hit the case anywhere.

the belt hit the damn starter bendix !!! ( second reason is belt slipping on the variator, bad cvt tuning i guess since there is ZERO slippeage when using very heavy contra spring and too heavy rollers ( low rpm with such heavy rollers ).

why in the world would the belt hit the bendix, knowing for sure the belt doesnt ride that high on the variator
sure on the kickstand the belt almost fall out, but far from that in normale usage ( about 1/4 of an inch from the outer of the variator ).
just why ? this issue have been running since day one so its not my new cvt setup. i found parts of my old snapped belts around in the garage ( ok i admit it, also 2 in my clothing drawer... adhd usual organisation LUL ). they have the same straight scratch foudn on my naraku belt. and it only happens with the bendix on.

pinted the bendix so i know for sure, and you see its what happen.

yes the blask thing you see is actual belt residu.

with all i have put on that thing trying to get it working as it should, or at least half right, id like to keep the electric starter if possible, seeing how terrible chinese kickstarter is fragile ( can only find chinese parts, no taiwan. and Dio parts arent the same here ). 

If you don't have that issue anymore why worry about any thing? lol

because "i THINK".

at least 6 time i tought i fixed the issue but i didnt.

[kosmos]

Jun 26, 2023 18:16:56 GMT -5 br4inl3ss said:

Jun 26, 2023 16:53:02 GMT -5 kosmos said:

If you don't have that issue anymore why worry about any thing? lol

because "i THINK".

at least 6 time i tought i fixed the issue but i didnt.

didnt mean to laugh.  but, have you taken into consideration what I've said?   Have you had a problem besides how it runs, anything with the CVT since you last did something with it?  How did the belt fit, in the manner i talked about checking.  I'd be interested in knowing. 

If that bendix you showed on the OP, does it even line up with the belt?  If it does, I think somoene else mentioned this too, the only thing I can think of besides like a shredded splines or really warped crank is the driven pulley locking up because the seal broke.  You showed that video of yours and how it wobbled.  I checked mine and its not got any slop.   Very tight since it just moves in and out of the seal.

[br4inl3ss]

thanks.
everything in the cvt move freely and as they should ( beside the crank seal ofcourse lol it shouldnt move freely ).

the crank , even tho its made of paper ( cheap Glixal ), is as straight as a ruler.

the bendix do line up perfectly with the scratch on the belt.

the belt ( Naraku ) fit perfectly front and rear



and doesnt reach max height in the variator while riding, only on kickstand where it probably reached 9k rpm.

pretty sure it hit the bendix only when i use proper roller weight ( to get decent rpm, but cause belt slip ).
that would explain why it doesnt anymore while riding because im forced to use way too heavy roller weight ( low rpm but low belt slip ).

ive had many problems with it... thus why the whole cvt is brand new, and with QUALITY parts ( Naraku / NCY ).
it fixed many problems i had, and now the cvt seems to operate extremly well. but this belt slip issue and bendix.

what cause the belt to wobble at the top like that ? its pulled not pushed... i dont understand how its possible.

[kosmos]

that video you posted of your clutch driven pulley, had some slop in the movable face around the seal. I had a bike once that a too tight belt wore that seal and it locked up the driven pulley in the shifted, open position. it stayed that way until I got home. Thats probably what happened to yours. so you were going along, probably shifted down into second gear, the rear pulley was in small mode the front pulley was in big mode. when you slowed down the front pulley allowed the belt to fall back down and turn the front pulley into small mode. so 2 small pulleys = a bunch of slop and the belt flung around and bounced around and slapped the bendix, probably got tangled up somehow and like mine, snapped the belt.

[br4inl3ss]

thing is it still slop, and i got a quality and in perfect condition rear pulley ( the whole cvt is new ).

still having this sliping issue.

i have ordered a quality carb ( dellorto phbg 19 DS black edition ), it was in stock but not really. so i should get it next week. i'm now thinking my roller weight are too heavy for my engine output because im running way too rich.
it make a bit of sense with my symptomes.
i mean... an engine runing way too rich doesnt get much rpm and low power.... and i am running way too rich.
so maybe, just maybe, my slipping and low rpm issue are fuel related. slipping because rollers are not heavy enought, and low rpm because no power is produced.

[kosmos]

id say carb. tune and tune the carb. i dont think you have any belt slip any more. if something busts its not from slip. its from my opinion if the belt is too tight causing things to break. id go with a longer belt if it done it again, and check the length how i described. as long as you're using an oem type driven pulley, oem type variator and oem drive boss, then widths and angles are the same. rpms lowering is what you say, does the bike kind of lunge forward as your holding it wide open like its not a smooth even forward torquing, like it maybe seems to sort of like your motor is missing a few strokes a couple of times but then jumps back forward kind of unevenly as you go down the road? could be rich. then you'll have to juggle the pilot and needle to sort everything out.
I found out I was too rich on the main jet, then i played with the needle next on mine, then discovered the pilot jet was too rich. then i juggled back again with the needles to get it going right. If you have a CHT gauge it will help a lot to tell you if your too lean or maybe even too rich a lot.

[br4inl3ss]

Jun 30, 2023 18:48:40 GMT -5 kosmos said:

id say carb. tune and tune the carb. i dont think you have any belt slip any more. if something busts its not from slip. its from my opinion if the belt is too tight causing things to break. id go with a longer belt if it done it again, and check the length how i described. as long as you're using an oem type driven pulley, oem type variator and oem drive boss, then widths and angles are the same. rpms lowering is what you say, does the bike kind of lunge forward as your holding it wide open like its not a smooth even forward torquing, like it maybe seems to sort of like your motor is missing a few strokes a couple of times but then jumps back forward kind of unevenly as you go down the road? could be rich. then you'll have to juggle the pilot and needle to sort everything out.
I found out I was too rich on the main jet, then i played with the needle next on mine, then discovered the pilot jet was too rich. then i juggled back again with the needles to get it going right. If you have a CHT gauge it will help a lot to tell you if your too lean or maybe even too rich a lot.

thanks. did you have time to read ? i think not.

all this have been stated many many many time... ALL of those...

cannot get better belt fitment as right now. next belt would be too long AND too wide, no fit at all.
my Naraku belt is near perfect. near the perfection those heavy tuners chasing .5mm fitment want.
i showed that many time already. my belt is of the correct size now.
it seems "glove fit" even tho only you talk about that. glvoe fit might be different for everyone, but i think its wat i have right now.

i know i'm running way too rich. stated it at least 10 time in my last 2 thread, including this one.
i dont need a EGT i have 100 time better : a wideband air fuel ratio meter. and a quality one not aliexpress or aem crap.
the only setting i can get so it start and run is 10.0:1 ( or more, its gauge limit ) to 11.5 from time to time. not related to throttle or rpm. its related to how this retarded carburetor feel.

i wanted to uninstall it, but those damn carb is impossible to tune at all. 2 point difference in jets and its wither way too rich or way too lean. it should be different but not that mutch.
just not sure its causing such issue.

once again, forget OEM type parts. they're near impossible to get or terrible quality, worse than Glixal crap i had.
went with QUALITY parts instead, Naraku and NCY. those are sport or racing only, tho. they fixed all the cvt issue i had in the past but this one. so i call it good.
it was already hard to get those.... imagine getting what you talk about.

[GrumpyUnk]

If you have a problem starting... does the byvalve work? Have you checked the two things that seem to make it inoperative? The probe extends/retracts or it doesn't. The 'well' built into the float bowl either gets fed fuel or it doesn't. You can test the probe action with 12v. You can test that the well is able to fill by removing the bowl, and putting fuel in, held upright. The tiny (pinhole) in the bowl allows fuel to slowly seep into the well. In case unfamiliar, the well is a tube-shaped hole built into the side wall of the bowl. The brass-looking tube from the byvalve pokes into the tube when assembled, and uses the fuel to feed the 'choke' (pseudo) that is almost essential for cold starting. If the byvalve does not work, it will be muy difficle to get the engine running, and many will fiddle with the idle mix and idle speed in an attempt to 'cover' for a failed byvalve.
Someone ought to do a write-up on how the dang thing works.
tom

[kosmos]

i'm saying that your cvt problems are over for now. that mark on your bendix was the cause of the rear driven pulley getting stuck open because.. a too tight belt caused the seal to bust, then it stayed open and didn't close and your belt was flapping around on 2 small pulleys, instead of them working together. belt flopping around, smacks your bendix and gets busted.
i recently had too rich of a carburetor problem. i went up and down with main jets, then tried adjusting needles, richening them, leaning them just to see if i could find the problem. i changed needles and everything but the rich issue wouldn't go away. it would show up on full throttle, on the main jet. so i leaned the pilot jet. then everything started working better. i adjusted the needle a few times and then finally got it.
so my rich issue was showing up even on the main jet, but it was the pilot jet that was too rich ended up being.