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

[br4inl3ss]

thanks
my very bad english want me to ask, what do you mean "and its cutting out immediately" ?

meanwhile, i got my jets and tested 100. its too big. put back my 98 ( that was way too small 2 days ago ) and when i'm able to get it to accelerate half decently, its fine. maybe a bit too rich but it works ( wideband usually stays at 13.5:1 - 13.0:1 but goes leaner from time to time like hit 15.0:1 or 15.5:1 for a second then back to usual rich within 13's ).

lowered the needle clip one notch since according to my HARD-TO-CONCLUDE test ( never the same ), it was a bit too lean from 1/4 throttle to around 3/4. it seem to ahve helped alot, but hard to say with the other problem. sometime even if i go slowly ( usually after giving many quick throttle in a row ), it will stays very lean for a long time.

for air leak, thats 80% of the problem. i cant find ANY. im also convinced its the cause, but what can i do if its impossible to find....
wasted whole day again waiting jets and trying them only to find out that i dont need them at all, at this precise date ( probably will be different tomorrow, it usually always been like that with any carb even tho the bhbg LOOK fine for that ), so im pretty much done for today. once again.

tomorrow ill try the smoke test once again ( did only 2 time and it was before the bbk and before the replacement CVK carbs ).

[GrumpyUnk]

Add to that, on the CVK, the accelerator pump & linkage.
tom


 A wideband sensor can show ratios all over the map and in one sense should be ignored.  When you are accelerating, you are working your way through the stages built into the carburetor.  The TRANSITIONS from stage-to-stage can have bumps and valleys in the mixture which would show on the wideband, but are actually part of the design.  The designers try to make it as close to stoichiometric as they can, but will have bobble spots.  More expensive(in some cases) carbs MAY have better transitions and thus mixtures closer to perfect.
 You may be chasing your tail in some respects.  Perhaps put a cover on the wideband and just sense how it feels overall as the rpms and speed change.
 I do not have a meter, and just more or less check for stumbling during acceleration, or hesitation when opening the throttle all the way at differing speeds.  I did have one that I could not get to work properly.  I think the diaphragm was too stiff or perhaps it was incorrectly fitted, and did not allow the slide to move properly.  It went back into the box of carbs and was substituted by another that did not show the stumble.  I cannot keep track of which is what... more or less.
tom

[br4inl3ss]

Aug 12, 2023 7:25:14 GMT -5 GrumpyUnk said:

Add to that, on the CVK, the accelerator pump & linkage.
tom


 A wideband sensor can show ratios all over the map and in one sense should be ignored.  When you are accelerating, you are working your way through the stages built into the carburetor.  The TRANSITIONS from stage-to-stage can have bumps and valleys in the mixture which would show on the wideband, but are actually part of the design.  The designers try to make it as close to stoichiometric as they can, but will have bobble spots.  More expensive(in some cases) carbs MAY have better transitions and thus mixtures closer to perfect.
 You may be chasing your tail in some respects.  Perhaps put a cover on the wideband and just sense how it feels overall as the rpms and speed change.
 I do not have a meter, and just more or less check for stumbling during acceleration, or hesitation when opening the throttle all the way at differing speeds.  I did have one that I could not get to work properly.  I think the diaphragm was too stiff or perhaps it was incorrectly fitted, and did not allow the slide to move properly.  It went back into the box of carbs and was substituted by another that did not show the stumble.  I cannot keep track of which is what... more or less.
tom

thanks.

i was using the wideband just to help me since i had problems all aroubnd ( cvt problem that felt like carb issue and so on ).



i removed it, same shit hapens.

i should state that i cannot get a STABLE / smooth idle at all. it either feels like missing or rev at least 2500 rpm to feels almost smooth. same issue with ALL the carb not just the phbg. altho i have to state that its WAYYYYYYYYY better than with any cvk.

its like bum bum BUMBUMBUM bum bum bumbumbumbum BUMBUMBUMBUMBUM bum bum bumbum bum bum bum bumbumbumbu.. yes you can laught at that.



there is no way to use the choke even when cold. it become way too rich. but hey i dont care about it. if it start cold without it, i'm fine witht hat. its just shouldnt be like that according to everyone, be it internet unknowns, friends with phbg ( on 2 stroke ) and shops.



brand new crank seals ( yes again. so what ? lol ) but Naraku this time. should be good for at least a month i hope LOL. brand new ALL AROUND gaskets but metal head gasket ( cant get one fast enought so i removed the 1/4 of black paint that stayed on and used motoseal just to be safer. i shoudl try making one out of sheet metal. i dont see why it wouldnt work here if it worked for years in a 84 maxim engine....



re-checked for leaks, still none to be found anywhere. ill do a smoke machine once again soon. i have plantar fatiscit or whatever its called in english so my heel become painfull after 3-4 hours of standing up. so i have to take a seat after 3-4 hours. done for the day.

i understand what you said. i know how a carb work in a basic way so i know all of that. what fuck me up is that many people did install phbg on 4t engine and none have ths problem.
and its not related to slide position ( throttle position ) its related to QUICK throttle only after 4-5 shot on center stand, and ALWAYS when on its weight. let it idle alone for 30 to 60 second, i can do quick throttle and work fine but after 3-4 shot the story repeat.

it really feels like fuel starvation, even tho it flow good ( or look like, at least ). or my float height if completly off. but ocne again there is 2 version everywhere. "float should be parallel to flange" and " all dellorto float height is perfectly fine from factory".
mine came a bit slanted ( it was brand new i could tell its never been touched ). so i made it as straight as i could.
not sure this is right tho... again different opinion, and they're contradictory.

here's how it sit right now ( i repeat tho, i can give any throttle i want it will run without much trouble, not after 3-4 quick throttle then now the very lean quick throttle start to happen ).









seeing 345035730568204986 different opinion on float height, i tried to get  DELLORTO user manual. only the same nosence contradictory things, and nothing official from dellorto. 

[GrumpyUnk]

Second pic looks a bit more 'level'. I have a 2T kym Super 9. I could not get it to start, cleaned the carb, etc. No go. Replaced the rings. Still no go. Got a battery and cranked. Was finally able to get it to start. Tried riding. Ran out of fuel. Most 49cc could run 1/2 mile on a float bowl full of fuel. Not this little piggy. I snorts with glee, and you can see bubbles move in the fuel line when you twist the throttle. Seems to me that is a LOT, but I don't do 2Ts.(well, not very well) So, it sits. Finally did get it to start and run at idle, and took it outside. Well.. that's when I rode off, and pushed it back.
It seems it can draw more fuel than the tank can supply. I thought it could be low vacuum causing the petcock to close up and choke off fuel supply. Next try will be a 'tank' made from a plastic coke bottle held in my hand w/o a vacuum petcock.
I got no clue, but think you have starvation. If any of the fuel lines are OLD, replace them. Could be turning to rubber spaghetti internally and you'd never know. Cheap.
BTW, some of the yellowish fuel line from DaRiver turns to rock after being touched by E-10. Apparently.

tom

[br4inl3ss]

thanks Tom.

it does in fact look like starvation. but that would mean id need a custom made petcock that allow twice the fuel to pass.... it SEEMS to flow anought fuel. but yeah maybe it doesnt like the vacuum activated petcock and its too slow for him ( the phbg )

it doesnt mean much but i tested something while changing my hose. i can clock the fuel line for 2-4 second and some time after ( maybe 5 to 10 sec ? ) the idle will drop and bog the hell out then catch slowly with time. then tis back up i test again but this time with quick throttle, and it seemed worse.

could it be my exhaust ?
a friend jsut told me he had a very similar issue with his scooter and it was the exhaust ( but it was a 2t and we all know 2t are very picky about exhaust ). it was a 2009 keeway f-act 70cc athena racing ( not sure of the name... but it was an athena with only ONE ring and cylinder was aluminium ).

i did test with a bottle as a tank without petcock, but all i had was a bottle that i need to keep so i couldnt open the other end ( hose thru the cap, so no opening at the bottom of the bottle ). ill test that when i have a bottle i can trash.

also is it normal to see bubble in the fuel line ? especially with throttle.

[br4inl3ss]

UPDATE
well my cylinder / piston is done.
oil pump stopped working. even the crankshaft bearign doesnt get any oil. after 2 minute of turning the engone on the impact wrench its ALL dry. and no passage clogged.

i always tought it would overheat if its not oiled... didnt overheat it just went extremly lean and bam engine completly locked.

not that easy to see on the photo but we can clearly feel it with fingers. REALLY.




i just have to hope my 81cc 50mm will work without too much compression while i order another bbk. ( yes oil pump on the way )

[GrumpyUnk]

The piston/cylinder/rings are lubed TOTALLY by splash. Splash being the crankshaft slamming into the oil in the sump and causing it to splash.
The pump only supplies the cam/rockers via the studs that mount the cylinder & head. If you look near where the above pics were taken you will see a ~1/8" dia hole in the top of the block, I think top left quarter, right near the stud. On the bottom of the cylinder is a groove that goes across from where the hole is located to the stud. Oil flows out the hole, around the stud, and then from the boss on the top of the cylinder head, through a groove in the rocker arm carrier. I think.
Main bearings are ball bearings that are also lubed by splash(pretty sure there are no passages in the block).
If your main bearings spin freely without any 'grind' or 'roughness' as you rotate, then they and likely the big end con rod bearing are fine. Check for slop on the big end by pulling/pushing along the direction of the rod, and rock gently side to side. If no noticeable wobble, should be good.
You may have overheated your piston/cylinder/rings with a too-lean mix. Assuming that your blower housing shrouds are intact and in place and reasonbly well sealed.
If your starter motor works, you can support the connecting rod and engage the starter. If the oil pump works, you should see a 'drool' of oil come out of the area where the cylinder base is gasketed to the block. The lowest(base) gasket should have a transfer groove.

Looking closely at the top pic the oil port hole can be seen in the lower left, directly above the stud. Oil should come out there.
The pump is chain driven from the crankshaft sprocket. You MUST get the right size pump sprocket to match the current size crank sprocket. I think number of teeth... and you have to disassemble to count, AFAIK.
Two different sprockets are used. Not sure on the chain. Crank and pump must match. Beyond that you are on your own.
Test with one hand keeping the con rod from flopping too badly, and give maybe 10-15 seconds of cranking. (a random guess).
tom

[kosmos]

does the cylinder feel like it has grooves in it? did it kick over after it seized or make any scratching noises? maybe it just lean seized, shut down, and your still good?
just for next time or whatever, what I meant by when you go from no throttle to wot, and in your video how it cut out, you were revving it back and forth then let off and then done it again, and thats when near the end of your video where it started to cut out. does it ever do that just from straight idle without revving it up, when you wot rip it back, does it do that; cut out like that? i would say either if it does that, its an air leak or pilot jet or mixture screw setting problem. have you tried many times, changing to a richer pilot jet, and adjusting your fuel mixture screw up from like the 1 1/4 turns out up to 3 and seeing if that stops? and if you cant ge tit to stop, richening the pilot jet again, and then again, and again? going through that? if you cant get it to stop doing that by the time your in everybody knows your in rich territory then I'd have to say it's an airleak. make a proper air leak tester. if that doesn't show anything then remove any mods you've done. i had an airleak that wouldn't show up on a pressure test and when i took the last part off that was acting funny anyway, and returned back to my stock oil pump, my tuning issues went away. (except for myself)

[br4inl3ss]

@grumpyunk
there is passage to lub the bearing. the outside at least. ima take pics.
anyway, absolutly nothing comming out of the pump at all. not even in the passage connected directly to it.
that means no oil going to the camshaft.
just to clarify one thing, the oil pump isnt used to lube the cylinder ( its only splash like you said ) but also serve as cooling. had a honda engine from the 80's that used a very similar design. oil passage was clogged and it overheated on idle even after 5 min. unclogged, same idle same time temp was 25f lower. thats just at idle imagine when riding.

crank are 16 or 22, and gear i dont know both but one is 47. impossible to mismatch they wont even touch.
and 22 tooth crank are for newer models. 2016+ i think but not sure.
glixal crank, even thos its terribly soft, have absolutly NO play but from side to side which is normal.


kosmos
there is scratch a a good groove. there is also a good groove in the piston ( intake side, on the side, matching the groove in the cylinder ). found a part of the piston skirt ( yup exactly like stock piston did ) on the crank "shield". no idea what its called but its like a separate part of round sheet metal. doesnt exist on the other side. anyway. so i didnt notice, but 47mm piston is also done with a missing skirt.

it was ofcourse lean... but its very ahrd to know that fast with the problem it have... alot of the time its lean for the first 2 minute of the ride ( but minor.. like 16 instead of 14.7, which isnt dengerous because stock they run even leaner ). i didnt have the wideband on, but by feel and noise i knew it was elaner... but the day before it was a bit too rich but acceltable. thats what i was saying , its never the same day after day.... only its the first time it change in the night with the phbg. its usually only with cvk carbs.

pilot jet is #30, the smallest available for phbg.. and it seems its way too small according to everyone..... but its what it needs. 34 is way too big the screw must be over 3 turn out. so 30 is what it needs.
i tuned it way richer at idle ( hitting 11.5:1 ), 1/4 mroe turn and it stall because tis so rich, doesnt change anything to this problem. tried all the jets i have from to to 50 even tho 45 is already way too big. its only too big never too small.

ill try to make it clearer about that it do.

#1: start it up.
#2: let it idle up to temp ( else it wont take any throttle not even slow ).
#3: be sure the choke isnt engaged, will never start ( too rich ).
#4:play with throttle how you want, it not perfect at all ( too rich and too lean depending on position ) but nothing to worry about.
#5: give 4-8 QUICK throttle ( up to any position be it 5% ot 100%, doesnt matter ), work fine.
#6: after 4 to 8 quick throttle, then its way too lean and then stall with consecutive quick throttle.
#7: at this point, even slow throttle it barely working.
#8 let it idle for 30 to 60 seconds.
#9: back to #4.

very hard for me to explain this...

main jets from 75 to 125 doesnt have much effect on it. needle either.
anyway i must reuse my 81cc bbk and hope it works without heavy detonation as with stock heads ( now using 47mm head ), so ill have to upjet. 
else my season is already done ( didnt even do 150km this season dammit ).

as for going stock, thats literally impossible. stock part doesnt exist, and "universal original style " are extremly hard to get.
literally the only mods on there is the bbk and in the cvt. the rest is stock or replacement. oh wait the stator have been upgraded from 8 to 11 pole, thinking my 4th stock stator was one of the fueling issue i had. nope. its just way betetr at charging at low throttle than 8 pole and deliver almost twice the amp for phone charger headlights and whatever.

i inspected the intake many time.. couldnt find anything. but as you said sometime it cannot be seen... couldnt get one in less than 1 mont, and for about 60$ with shipping ( and +30 for customs fee ). 50$ locally if i wait even longer. when i say they're very hard to get.... then they are very hard to get.

ill make another smoke machine and try that alter when its reassembled.

thsoe cheap crank are so damn soft wtf is that... dropped a pair of scisor from 1/8 of an inch on the crank shaft and its grooved....... tested to drop the same scisor from 3-4 ft away on the ALUMINIUM case i have on the table to cut gasket, and no scratch at all. those cranks are softer than aluminium the heck is that...
my brother saw that he made the biggest facepalm of his life. even jb-weld is harder than those crank. pathetic.
i cleaned all the groove and scratch on the glixal crank ( stock one is completly done ) and applied jb-weld on the groove. filed it down and fine sanded. i just hope it will last for the rest of the season. but it should, it lasted for YEARS on my 4wheller back in the day.
oh by the way the piston skirt part damaged the crank shaft thats why it wasnt such a bad thing that the scisor scratch it. had to do something anyway.

ill get a Naraku crank. been told they are not made of waxpaper like chinese crank.

[br4inl3ss]

there we go. oil does normally go to the crankshaft bearing.







but anyway... the oil doesnt even go out of the first passage. like there was NO pump at all.
and nothing clogged. it pass light test, water test, and oil test. passages wide open all around, even on the cylinder to the camshaft.
so it must be the pump.

[kosmos]

Aug 16, 2023 14:41:21 GMT -5 br4inl3ss said:

pilot jet is #30, the smallest available for phbg.. and it seems its way too small according to everyone..... but its what it needs. 34 is way too big the screw must be over 3 turn out. so 30 is what it needs.
i tuned it way richer at idle ( hitting 11.5:1 ), 1/4 mroe turn and it stall because tis so rich, doesnt change anything to this problem. tried all the jets i have from to to 50 even tho 45 is already way too big. its only too big never too small.

ill try to make it clearer about that it do.

#1: start it up.
#2: let it idle up to temp ( else it wont take any throttle not even slow ).
#3: be sure the choke isnt engaged, will never start ( too rich ).
#4:play with throttle how you want, it not perfect at all ( too rich and too lean depending on position ) but nothing to worry about.
#5: give 4-8 QUICK throttle ( up to any position be it 5% ot 100%, doesnt matter ), work fine.
#6: after 4 to 8 quick throttle, then its way too lean and then stall with consecutive quick throttle.
#7: at this point, even slow throttle it barely working.
#8 let it idle for 30 to 60 seconds.
#9: back to #4.

very hard for me to explain this...

main jets from 75 to 125 doesnt have much effect on it. needle either.
anyway i must reuse my 81cc bbk and hope it works without heavy detonation as with stock heads ( now using 47mm head ), so ill have to upjet. 
else my season is already done ( didnt even do 150km this season dammit ).

as for going stock, thats literally impossible. stock part doesnt exist, and "universal original style " are extremly hard to get.
literally the only mods on there is the bbk and in the cvt. the rest is stock or replacement. oh wait the stator have been upgraded from 8 to 11 pole, thinking my 4th stock stator was one of the fueling issue i had. nope. its just way betetr at charging at low throttle than 8 pole and deliver almost twice the amp for phone charger headlights and whatever.

i inspected the intake many time.. couldnt find anything. but as you said sometime it cannot be seen... couldnt get one in less than 1 mont, and for about 60$ with shipping ( and +30 for customs fee ). 50$ locally if i wait even longer. when i say they're very hard to get.... then they are very hard to get.

ill make another smoke machine and try that alter when its reassembled.

thsoe cheap crank are so damn soft wtf is that... dropped a pair of scisor from 1/8 of an inch on the crank shaft and its grooved....... tested to drop the same scisor from 3-4 ft away on the ALUMINIUM case i have on the table to cut gasket, and no scratch at all. those cranks are softer than aluminium the heck is that...
my brother saw that he made the biggest facepalm of his life. even jb-weld is harder than those crank. pathetic.
i cleaned all the groove and scratch on the glixal crank ( stock one is completly done ) and applied jb-weld on the groove. filed it down and fine sanded. i just hope it will last for the rest of the season. but it should, it lasted for YEARS on my 4wheller back in the day.
oh by the way the piston skirt part damaged the crank shaft thats why it wasnt such a bad thing that the scisor scratch it. had to do something anyway.

ill get a Naraku crank. been told they are not made of waxpaper like chinese crank.

woh wait.  30 pilot jet?  34 is way to big, and has to have screw turned 3 turns out?  the phbg uses a fuel mixture instead of an air mixture screw.  when you have to turn the screw out more it means you need more fuel and you are lean.  check the carb, if the mixture screw is on the intake side of the venturi where the throttle slide goes in, then its a fuel mix screw.  if its on the airbox side of the throttle slide, its an air mixture screw.  more turns out on fuel means you are richening it, more turns out with an air mix screw means you are leaning it.  meaning fuel screw turn out for + means you are running a lean pj.  air screw out for + means your pj is rich.

[br4inl3ss]

the screw is on the intake side ( not the air filter side ).
its an original dellorto one, not a clone.




also, how SHOULD the idle speed screw sits, notmally ? its easy to get a base setting on cvk but on phbg
like BARELY see light thru the slide ? more ? completly closed ?

air mixture or fuel mixture, thats making my brain smoke a bit... lol.

[kosmos]

the mixture screw is the little brass one on the left on that picture below and left of the big idle adjustment hand size screw. its for fuel. close to close fuel mixture off and open to allow more. if your turning it out and its not idling right and cuts out then the PJ is too lean. wow the 30 is like the smallest phbg idle jet. well now you can check what you were doing.
for the idle setting, turn it out until theres no more resistance of it pushing up on the throttle slide that is spring loaded pushing down. look down the carb, and slowly turn the idle screw in until you see the throttle slide start to open. From there start it and only turn it in enough to keep it running. adjust mixture screw while revving back to check for cut outs, and turn up the idle screw only a little to keep it running if your idle rpms starts to go down. but start it out at a low rpm when you start to tune the Pilot Jet.

[br4inl3ss]

Aug 17, 2023 2:02:52 GMT -5 kosmos said:

the mixture screw is the little brass one on the left on that picture below and left of the big idle adjustment hand size screw. its for fuel. close to close fuel mixture off and open to allow more. if your turning it out and its not idling right and cuts out then the PJ is too lean. wow the 30 is like the smallest phbg idle jet. well now you can check what you were doing.
for the idle setting, turn it out until theres no more resistance of it pushing up on the throttle slide that is spring loaded pushing down. look down the carb, and slowly turn the idle screw in until you see the throttle slide start to open. From there start it and only turn it in enough to keep it running. adjust mixture screw while revving back to check for cut outs, and turn up the idle screw only a little to keep it running if your idle rpms starts to go down. but start it out at a low rpm when you start to tune the Pilot Jet.

ok thanks. ive been given false information on the r/scooters subreddit and discord ( thats where one guy said its impossible to run a 2 stroke style carb on any 4 stroke  . i then showed 3 4 stroke dirtbike that came from factory with pwk aka 2 stroke style carb.. well i think they're pwk... not sure but they have the slide directly on throttle cable  ).

should i remove the #30 right away and put back the stock phbg #45 and try that ? not sure the info is decent, but they all told me the 45 should work fine on almost any configuration from 50 to 80+ cc. not a big deal i have to put a bigger main jet anyway since i had to put back the 81cc 50mm bbk.

[kosmos]

im at a 42 pj right now on my 2-stroke with a 72cc sport kit. id go somewhere around there. did you get the AN atomizer and change it out? I dont know if it will tune correctly on a 4 stroke if you're using the AU, but I've heard people do something to get it to work. dont remember what exactly