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

[br4inl3ss]

thanks alot.
its an AN 262, thats why i bought this dellorto instead of a clone ( impossible to get the info for them ).

i put the stock 45 pj back in, it refuse to start. it TRY to start if i turn the screw all the way IN but still refuse to start. giving throttle make it worse. the more i turn it in the more it try to start. ill put a 42 next time.
choke doesnt change anything so i guess its way too rich. my face is almost red of rage so i didnt check the plug yet after trying to start it for 45 min.
and the choke NEVER worked no matter what setting i ever used. always made it way too rich ( its usefull only when i give quick throttle to richen the mix when troubleshooting the other lean issue ).

but it look like its way too big as is. i also put a 115 mj since its now on the 50mm 81cc bbk to play it safe ( 98 seemed correct for the 47mm 72cc ).

thats the phbg i ordered and from that site.
www.maxiscoot.com/fr/produit/carburateur-19-dellorto-phbg-ds-30512?vctype_id=199
it state its AN atomizer, and its what is installed on the carb.
its in french because the english description is almost empty.

[kosmos]

is yours fuel pump or vacuum operated? When I changed my PJ the other night up to a 42 it took mine a few minutes of kicking to start it. Did you set the idle up any before? is it up too high? try adjusting it a little up or down some. Start with the mixture screw at 1 1/2 turns out or less instead to get it going.
Was your bike not as bad after the problem that you thought? if the scratch isn't very deep, you might of soft seized it. I dont even really konw what a soft seize looks like even tho I had lean problems forever. Did have a very not too good looking cylinder after I was done. My last stock cylinder looked pretty good after I took it off since I've fixed the lean problems

[br4inl3ss]

thanks.
i got it to start, no idea how...
but yeah i tried for a long time ( over 30 kick ) before it finally start.
gotta give it some throttle else it will never start ( and thats with the slide high because of idle screw )
pj 45 is way too big.
so big that i have to screw the idle speed screw alot to keep it running and its around 1900 rpm.
gonna try pj 42.


there is a BANG BANG BANG BANG BANG BANG noise comming from i think the crank. but its fine i can tell you that the crank iself is fine. possibly from bad fueling because it completly stop at 1900 rpm+. ill see.


EDIT
42 too big.
38 too big.
I get best idle quality and stable with mixture screw completely seated in.
started at 1.5 turn out as you said.

Going for a 34.

Edit 2
It's vacuum petcock. It seems to work fine. It does with cvk carb at least.


EDIT 3
With 32 pj i get a good idle with 1.5 turn out. Not super stable ( sometime it play around 1850 to 2100 ) but it's the best I can get.
It seems to go back to around 1900 rpm after I release throttle ( if I didn't go fast ofcourse ).

Still the same quick throttle issue with the 50mm bbk but on center stand it look a mini bit better.
Start very good when hot tho.... Better than ever.

Now I'll drop that main jet its way too big.

[GrumpyUnk]

never mind

[kosmos]

Aug 17, 2023 21:40:30 GMT -5 br4inl3ss said:

thanks.
i got it to start, no idea how...
but yeah i tried for a long time ( over 30 kick ) before it finally start.
gotta give it some throttle else it will never start ( and thats with the slide high because of idle screw )
pj 45 is way too big.
so big that i have to screw the idle speed screw alot to keep it running and its around 1900 rpm.
gonna try pj 42.


there is a BANG BANG BANG BANG BANG BANG noise comming from i think the crank. but its fine i can tell you that the crank iself is fine. possibly from bad fueling because it completly stop at 1900 rpm+. ill see.


EDIT
42 too big.
38 too big.
I get best idle quality and stable with mixture screw completely seated in.
started at 1.5 turn out as you said.

Going for a 34.

Edit 2
It's vacuum petcock. It seems to work fine. It does with cvk carb at least.


EDIT 3
With 32 pj i get a good idle with 1.5 turn out. Not super stable ( sometime it play around 1850 to 2100 ) but it's the best I can get.
It seems to go back to around 1900 rpm after I release throttle ( if I didn't go fast ofcourse ).

Still the same quick throttle issue with the 50mm bbk but on center stand it look a mini bit better.
Start very good when hot tho.... Better than ever.

Now I'll drop that main jet its way too big.

Mine took a bit to start up after I went to a large pilot jet, too.  Don't worry about the idling, just let it warm up some first then let the bike settle down at idle no throttle for like 4-5 seconds to clear it up, then rip the throttle back WOT.  If it cuts out without increasing rpms, raise the PJ.  32 sounds kind of small to me. Mine wouldn't idle with a 38 but I thought i wasnt having any cut outs.  Never seemed to have one.  I lowered it to 35 and it definately cut out.  So I went to 40.  Diddnt seem to cut out on me ither at first, and it idled without dying.  After a few rides it started getting cut outs when I'd take off.  Finally I went to a 42 and no trouble staying idling on its own, and no cut outs.

If when you go from a steady cleared idle to WOT quickly, the motor just dies, doesn't try to pop or anything, its lean.  With too little fuel it dies, with over fuel it will spark something and pop on you.  Im not sure if this behaves differently on a 4-stroke. since it gets 2 revolutions before it sparks.  

[br4inl3ss]

thanks. i cannot get bigger pilot jet else the screw must be out more than 2.5 turn out. thats bad.

for the quick throttle, it behave differently with the 81cc than with the 72cc.
1 to 30 quick throttle doesnt change anything,. ALL quick throttle to 1/2 or more throttle it want to die. no pop or anything. just the lean beuhhhh noise and it die. if lucky and it doesnt die then it get back to normal idle speed tho.

so i let the idle as is since it seems to work. bad, but work. ( yesterday it was fine with a good idle at 1900, today it barely hit 1600 and isnt as stable. pinned throttle wide open on center stand for like 20 second, not giving a fuck about knocking, and it went back to a decent 1900 rpm idle and kept it for the whole test time. so i guess its only when cold.
oh byw first start of the day it took like 7 sec to start and voila. bad idle and slow but starter.

what bug me down if the fact that there is no way i use the damn choke. they made me buy the polini choke handle because choke must be working to start when cold, even in summer. whick seems to be really true with cvk and thier auto enricher. no start at all without them.
so that bug me like hell.

anyway.... right now i'm with a 105 main jet and i'm not sure now if its lean or rich.... on center stand it reach 8200 rpm, but while riding doesnt go over 7400 and i feel some " hiccup " from time to time...
i'm trying to not rely on my wideband, but i have a feeling i will have to install it back t know for sure.... which i would hate, its getting slowly damaged by vibration.

when ill have done at least 50 km without it breaking down, then ill note the actual setup ( pj, mj, screws position, needle position, float position ) and then play with bigget pj as you stated, but i know even this 32 is on the edge of bein too big.

i may even ask to "ZOOM conference" a tune, at this point. ill setup my laptop with webcam and everything outside. hope i dont have to go this route tho. very time consuming.

[br4inl3ss]

Ok so i made another temp smoke machine and no leak anywhere....

I thought it may be my intake because there is a cut inside it, but no it doesn't leak at all.

I thought thenaybe it's a leak that only happens at higher pressure/vacuum, but to test with over 5 psi i'll have to make a better smoke machine.

Rain stopped so I'll be able to test ride with the wideband on, again. Tried to not use it anymore but I have both lean and rich symptom with 3 main jet. So not much else I can do than rely on the wideband again to know.

With the 72cc the 98 was acceptable. A bit too rich but ran decently ( the other day it was too small... Whatever I'm done with such change overnight ). Now with the 81cc the 98 it seems both too rich and too lean. I have both feels. Doesn't reach the rpm it should WOT ( but does on center stand with a bit of difficulties ) and I feel some 'cut' WOT.

Previously when it was too rich there wasn't any cut just not reaching decent rpm so no speed.

Right now it go slower then with the 72 ( 60-65 on 72cc, 50-55 at best on 81cc ). Fueling is definitely wrong. And accelerate way slower
Can't even follow my brother 50cc 4t vino while I was pushing it with the 72cc.

I'll try to figure out what I can use for a better smoke machine. I know how to make one with nichrome or kental wire but i don't have those insulated "connector" to seperate metal container to the circuit. No go that route.

[kosmos]

Aug 18, 2023 18:50:42 GMT -5 br4inl3ss said:

thanks. i cannot get bigger pilot jet else the screw must be out more than 2.5 turn out. thats bad.

Have to, more, for what?  to have it idle? or to have it not cut out when you flip the throttle up.
When you 'have to' turn it out more means you are; the PJ, is lean.

[br4inl3ss]

To get a decent idle...

Yesterday I tested again, got a very good idle no pop nothing, but at 2300-2400 rpm.

Then after a 45 min break, it start only if I give throttle and will not be at the same idle speed as previously. Sometime it will, sometime not.

I found out my air filter connection is cracked, but that's not an issue since it act the same without air filter. Only bliping throttle is worse. I'll fix that , but idle is more important right now. It I go somewhere and it refuse.to start again I'll be in trouble so right now idle is more important.

[kosmos]

don't worry as much about idling than about cutting out. I couldn't get my PJ set right and it wouldn't idle, and I thought I had the snap back going right, bike wouldn't idle, so I downjetted, thought it was rich. Don't konw about the idle at that point but it cut out worse, so I upjetted. Thought it wasn't cutting out and it idled better. Then later found it cut out at some points, so I upjetted again. Haven't had a cut out and the bike idles fine. Idling and cutting out are 2 different things. Let it warm up first and check cutting out whne you snap back the throttle to WOT. It should from my experience, idle fine after that.

[br4inl3ss]

found out my aidbox tube it worse than it was. its not my whole issue tho.
found a big exhaust leak at the flange ( those bend with head so even the gasket become completly useless ).
that was probably the reason my wideband, when used ( gotta repair a connector so wont be useable very soon ), was showing funky air fuel ratio that didnt match performance and feel.

so since my best idle was with 30 pj i put it back on and be done with it for some time.
now on the more important issue.... did a test ride with the 98 mj. terrible.
went to change the jet but mid job had to leave so i just put the carb back on. no jet changed, nothing.
went back, put the 102 mj, way too rich. like the spark plug was already full of carbon, barely hit 5000 rpm, and doesnt go over 45 and slowing down it throttle was kept wide open. to get back home i had to sue only #/4 throttle ( too rich but still leaner ).
once again i went to drop the main jet to 100 but couldnt finish ( just removed the airbox tube ) i had to leave again.
back at home 45 min later, i forgot i wanted to drop the jet a bit ( damn tdah and have to stop workingevery now and then ) so i just did a test ride without connecting the airbox tube to the carb. i knew right when i started it but no fucking way ill remove the damn seat once again jsut to connect that. and then wanted to test as it anyway.
what a change. runs way better than the previous ride ( still on 102 mj ).
not perfect and didnt check the plug. but the noise it make without air box is worse than 2 stroke with the big evo pod filter from polini.

since im done with cheapo parts i wont buy another "stock" airbox. pod filter are overprice right now even on amazon so nope. i remembered seeing a nice motoforce kart air filter from scootertunign and Importation Thibault catalog... out of stock. ah ofcourse. so ill try to fix it using vac hose or something. when fixed if it need more air then i dont know what to do ire not restricted so not much to be done.

EDIT
went to the city hall today.
no air box, 102 main jet.
62-65 km/h all the way and i hit 68 for a very short time. ( when i first tested the cylinder with stock head i was hitting 80-85 pretty easy on decent distance distance before it start to ping like crazy )
dont forget its the 81cc 50mm cylinder with 72cc 47mm head ( btw im happy i have no knock so compression is not way too high as with stock head so i can run it this way for the rest of the season even tho its a bit damaged ).

and here is the plug after that ride ( yes, long run WOT and cut directly. no idle time and plug was checked 40-45 second after bein cut ).



but that damn bog on acceleration on quick throttle ( and sometime slow throttle, like the fuel didnt get in the bowl fast enought even tho it does ) fuck me up. but whatever.

[kosmos]

dont worry about the idle just up the pilot jet, fix any air leaks first, then rev it back, adjust the mixture screw up to 3 turns out.  sometimes you can overshoot and it will make it bog from rich too, but itll be a bit different.  and get it to not cut out on that initial rev back.  be sure your main jets within acceptable range not over 1 or 2 sizes off.  and the needle is somewhere inbetween or if you've already tuned it, leave it there.  the idle should follow.  make sure the throttle stop, idle screw, isn't opened too much, or too little while your doing this.  and for that I dont really have a range but a little bit is ok, beyond just cracked open.  If you go down the road and notice it cutting out later like I did, retune the PJ again.  
 
for the exhaust flange, I put the exhaust bolt in, loosely and then I push the exhaust up on the flange as centered as I can, make sure your using a good exhaust gasket, and tighten the nuts down while holding the exhaust centered.  tighten the exhaust mount bolts next.