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Discussion Starter · #1 ·
hello. i got a phbg caruburetor 21mm. i use a 72cc bike 2-stroke. this isn't a mini its a little bit bigger. im just trying to figure out how to tune this carb. i need somebody who knows how to tune a dellorto. whats going on when you turn the screw. i cant figure out some basic stuff.

like what does the motor do when you cut off the fuel mixture screw? an air screw carb, well, depending on how much fuel, it would just quit. im just wanting to know, what a tuned scooter would do when you cut it off. on this carb. i would think it cuts the mixture off, bike dies, all it has is fuel from the next jet.

so i got this bike. well. so watch this video of it. i turned the screw in almost every direction trying to tu.. ok. there are 2 videos. at teh beginning of each i try to tune some. turning the pilot screw. and turning the idle stop screw. the first video, which is actually the second, i made it after, is just tuning the carb. this is whats going on. i do a little trick
ok. stock jetting. i start it up. or its running there. the mix screw, oh 1 1/2 turns out. turn the idle screw, got a good idle. ok, so then i turn the mixture screw. i turn it out, nothing much happens. i turn it in, revs a little higher, gets to where its almost off, revs pretty high. close off the fuel screw? it makes a little whistling noise and revs the highest... ok. so maybe its somethign to do with pressure. i lower, the idle stop screw, turn it out, you know. it gets pretty low rpm. then i turn out the mix screw, wondering if it will kill it, it for a second seems to drop, then it starts revving higher. after 1 1/4 turns it starts to stall.

ok. but if you read the manual. it says well, they shut off the slide on racing bikes. and tune it with teh idle at 1400 rpms. then you tune it to around 1200 rpm, you knmow for idle. after setttign their tune, racing bikes, close the idle stop screw by turningn it out until the slide is closed.

well. seems like the slide was close to closed and mabe instead of tuning my bike i was doing that.

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im thinking i might be tuning with the slide closed. or myabe it was close. but. they say in the manual. tune at 1400 rpm. turning yoru pilot screw. then set idle to 1200 rpms. then if you have a racing biek they sometimes turn the slide down so when they wreck, it quits. well.. it says they do that. doesnt say they wreck or it quits.

and they say dont turn the mix screw after youve done this you can seize it.

so what am i doing? ive just down a leak down test and it didnt leak. sealed off everythign and no leaks. the only thing not tested, would be my new vacuum line, i thik does work when i suck on it, it doesnt leak air. and the rubber around the carb. one thing i sort of squish it a little, i use this intake. http://www.scooter-center.com/scowe...arget=productdetail&category1=A&category2=CAT
ive got another intake i could switch. i had to change the reed cage cause it leaked. so i switched to that intake. is a 23mm connection rubber too small? for a 25mm connection intake? the intakes not leaking aroudn teh base or anything. it has a rubber connction around it thats 23mm and the spigot on teh carb is 25mm. i sprayed starter fluid around the spigot on the carb near the rubber. didnt check around the intake and rubber. i tighten it a little too. cant think of anything else this would be.

the two videos. https://vimeo.com/44081952 and https://vimeo.com/44082663
 

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Discussion Starter · #2 ·
another question, in the riding video, i dont know if anybody knows, are themn safe temps? 140 take off, hadnt even idled for long. just had warmed it up before, or tried to tune the carb. think it idled for.. wait. i idled it outisde for 4 mintues it was 180 degrees. i took it in, cooled it off went back outisde started it up and made that video. 140 start off. 1/4 mile later, 90 degrees hotter, 250 didnt cool down for the 20 seconds i sat there but maybe 9 degrees. i was idling. came back, 290 degrees. not over 40mph and not over 1/4 throttle main jet isnt too lean, its too rich. cuase i came down from way higer. 122 main 118, was first, then it had a 112 in it and didnt do nothing but flood out with it past half throttle. and the temp didnt raise.
 

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Discussion Starter · #3 ·
info on what i got. 11,000 rpm motor 11hp, 11,000 rpm pipe. 21mm dell carb 46 pilot w7 2nd notch down needle clip 112 for now, main jet. uni-filter. #6 ngk heat plug for the oily breakin oil and low speeds. about 45:1 quicksilver oil mixture. if you know what quicksilver is. marine, for bikes too. someone said it was thick is why i got it mixed like that. ok. so someone know anythign to help me? thanks.
 

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is that a water cooled or air cooled? If its a air cooled the temp is about right if its water cooled you need to bleed the system of air and or check your water pump belt.
 

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Is that a stock main jet for the carb or the bike either way I think it's to lean. Is that a new carb or did it come on that scooter? The main jet only controls from 3/4 throttle to full throttle. The needle goes from idle to about 1/4 throttle and the pilot jet as 1/4 to 3/4 throttle.

Set your idle where it tells you to set your rpm/s for idle. next you what to tune the air/fuel screw. set at 1 1/2 turns out. Set you scoot on a stand. What you want to do is start it let it warm up than romp on the throttle and let go and listen . you want to hear it settle right down when you let off the throttle. Turn the air/ fuel screw a 1/8th turn at a time romp on the throttle and let go until it settles right down and doesnt hang onto any revs. Once you have this tuned your ready to ride and start tuning the main jet by high speed runs and once to high speed while holding your throttle without letting off hit the killswitch until it dies. check the sparkplug and change the main if it looks lean or too rich. You have to tune in the right order or you will chase your tail all day. Also before you start tuning if it will idle check the entire intake area for air leaks.
 

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Discussion Starter · #6 ·
yea you didnt botgher to watch the video then. 290 degrees? for 1/4 throttle, oh ok so 450 is a good full throttle, if i was to go by temps and throttle pull. and just multiply. no thts too hot.

in 1/2 mile ive not got my scooter to riding temps at /14 throttle. 290 is letting off the throttle temps. ok yea its a/c. an a/c motor. maybe if you looked at the video, then you could of maybe seen that. theere werent no big hoses coming from the motor. HWO HARD COULD IT BE TO CLICK THAT SITE? dont respond unles you watch my video. and no your tuning method seems like a leak tuning idea. NO. thyen just bypass the temps? NO there too hot. 350 is the max you want to let it sit at. this motor will break. i know that. ****ing 290 degrees 1/4.. so wht at half throtlte i should see 580? is that right?

watch my video, the temps dont lower. its right up there, you dont even bother with it. according to my video, im tuning the idle differentlyu than you. it actually reads in the book to do this. and if you watch my video, thenn what am i doing wrong? whats going on? there where no leaks. ive checked with starter fluid. just not around the rubber to intake, but its a big piece of rubber. wasnt thinking it was exactly leaking but i do tighten it a bit. i cvouldnt get my exhaust to quit leaking when i leak tested until i loosedned the bolt because it was scrunching up the intertube gasekt i made.
 

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Discussion Starter · #7 ·
is 112 a stock main jet? no. its not. its arich main jet this isnt a stock carburetor or a stock motor. or stock exhaust, manifold reed cageporting, reed cage, intake manfild. just to answer some questions.
 

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Discussion Starter · #8 · (Edited)
wrong wrong wrong. 290 i might as well run 600 degrees at full throttle. wrong wrong wrong. my high temp case sealer only goes to 600 interminteally what you think im ****ing retarded or soemthing?

****it. **** this i think the choke circuit is messed up. if i blow thru the starter jet, which is what the choke runs on, if choke is openned free flow air. if closed, shoudl be closed. it leaks air. blows air i can hear it, where its going? all around the bowl
 

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Discussion Starter · #9 ·
if i just start it up and let it go. then how do i ever know if the pilot jet is jetted. and you dont jet the pilot by revving the throttle. and messing with the jet. according to the manul, it revs at certain rpms. ive never read the book to 1/8 throttle, cuase i havent go there. **** so quit going there without me doing it.
 

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Discussion Starter · #10 ·
i AM UNABLE TO JET MYSCOOTER PAST IDLE ACCORDING TO THE MANUAL. DONT TELL ME TO REV IT UP. CAN SOMEBODY READ ON THIS PLCE OR DOES SPAM REQUIRE YOU TO READ?
 

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Dude I watched both videos all they show is you trying to turn the dang screws all over the place. you only turn that air/fuel screw a 1/8 turn at a time and test not turn it this way and that way. Of coarse its going to get hot sitting and idling and just turning the throttle. It needs air to flow over the motor to help cool it. And it shows that from your little ride what it show like 240 degrees when you stopped and showed it. I run a phbg 18 and 19 and have no problem tuning them. I tried to help but Im jumping off this bus good luck...............
 

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Discussion Starter · #12 ·
you helped? yea then good. glad your gone if thats your reply.

290 degrees i mentioned that to someone and they about crap themselves and your spewing this info as legit good info to follow. are you crappingme? gotta be joking. whatever. good.

yea and to get air flowing my bike needs to run. my bike has afan shroud and a fan. it gets air by blowing the fan. doesnt require running. 240 degrees at 1/4 throttle then 290 on the way back, is hot. especially when 340 is max temp you wanna see. on this motor ive got. i dont even understand what your saying, of course it s going to run hot sitting.
you rode your little ride and it showed 250. ..
so you are being a hypocrit. you said one thing then another without even taking a breath. you give bad advice. you mentioned my temp. thats about all you done. i said its too hot. you said it shows that. what i said. so what? you said nothing. quote me then talk about how your better then leave? FINE GOOD.
 
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