dellorto PHBG 21 mm carb setup

i still use the stock pump with my PVL inner rotor ignition but this one needs a pro tuner to install & tune, Malossi inner rotor ignition will be much simpler but not quite as good as PVL, btw you will lose all your lights if you run this type of ignition but Polini makes one that still uses lights.
 
i still use the stock pump with my PVL inner rotor ignition but this one needs a pro tuner to install & tune, Malossi inner rotor ignition will be much simpler but not quite as good as PVL, btw you will lose all your lights if you run this type of ignition but Polini makes one that still uses lights.


hello tiba. is high octane fuel better for the engine? also were would i look to buy this fuel. it was just on my mind thats all. also are kevlar racing belts worth buying. ;) thanks.
 
hello tiba. is high octane fuel better for the engine? also were would i look to buy this fuel. it was just on my mind thats all. also are kevlar racing belts worth buying. ;) thanks.
I'll tell you what I experienced. I've been running 93 octane fuel from the pump and thought I heard some preignition going on so (on the advise from tiba, I put in some 110 octane race fuel and didn't really hear any difference. Then I posted those engine noise vids and tiba said that the noise was normal (reeds resonating), so I won't be buying anymore race fuel soon as it cost $5.89/gallon US. In summary, race fuel was not necessary for my bike.

Now to answer your question about whether it is better for the engine or not, the answer is that low octane fuel has a higher potential to pre-ignite from the heat of compression before the spark ever fires. High octane fuel then has a better resistence to pre-ignition. So if you think that your bike might be pre-firing the higher octane fuel will resist firing prematurally and therefore guard against detonation, that's all. Read this:

http://www.bajajusa.com/High Octane.htm
 
I'll tell you what I experienced. I've been running 93 octane fuel from the pump and thought I heard some preignition going on so (on the advise from tiba, I put in some 110 octane race fuel and didn't really hear any difference. Then I posted those engine noise vids and tiba said that the noise was normal (reeds resonating), so I won't be buying anymore race fuel soon as it cost $5.89/gallon US. In summary, race fuel was not necessary for my bike.

Now to answer your question about whether it is better for the engine or not, the answer is that low octane fuel has a higher potential to pre-ignite from the heat of compression before the spark ever fires. High octane fuel then has a better resistence to pre-ignition. So if you think that your bike might be pre-firing the higher octane fuel will resist firing prematurally and therefore guard against detonation, that's all. Read this:

http://www.bajajusa.com/High Octane.htm

Thanks i didnt know anything about fuel till know. have you used one of them oil/fuel ratios tiba posted. i tryed 25:1 and couldnt see haha. i think that my bike runs best at around 40;1. what is your apinion on oil/fuel because more oil in the mix and it makes the engine leaner i think is that correct?.
 
we run between 30:1 to 25:1, we like to have a bit more oil in the engine for better seal on the rings & longer engine life. running less oil won't make more power, it is quite the opposite & it's dyno proven.

the more oil you mix it leans out the fuel to air ratio so you compensate for that by running slightly bigger jets.
 
Thanks i didnt know anything about fuel till know. have you used one of them oil/fuel ratios tiba posted. i tryed 25:1 and couldnt see haha. i think that my bike runs best at around 40;1. what is your apinion on oil/fuel because more oil in the mix and it makes the engine leaner i think is that correct?.
I learned about fuel through many sources, but when I saw that SWAMI site, it was a blessing, because he <like he said> made a long boring story about fuel "short". And it has just the right amount of info to understand it.
That being said, our Polini Evo's are "a high compression cylinder" as the swami stated may be an argument for super-unleaded. I, as I stated, have found 93 octane to be sufficient all though 94 or 95 would be nice insurance if you can find it from a pump.

I am running the 25:1 that tiba suggested and yes, it produces smoke, but I get a good feeling knowing that all that much more oil is in there lubricating. As mentioned, the extra oil does lean the mixture, and what I am wondering from tiba is, if he believes that the extra oil replaces some of the mix that would have been gas, therefore reducing the "cooling effect" of gas on the piston and cylinder?:!
 
Thanks . i went to 50:1 last night and it ran much better. a little bit of smoke but it drove much better. im running 98 main jet and my next size up is 105 and i tryed that and its too rich bike hardly moves. i will buy an inbetween jet and run 25:1.
 
mine smokes a lot when you start it from cold but when it gets hot & you run it at WOT for a long period of time there will be no more smoke coming out of the tailpipe.

prolonged low rpm use usually dumps a lot of unburned oil inside the pipe which results in the smokiness that you guys experience.

once you tune the engine optimally ride it like it's stolen!
 
I learned about fuel through many sources, but when I saw that SWAMI site, it was a blessing, because he <like he said> made a long boring story about fuel "short". And it has just the right amount of info to understand it.
That being said, our Polini Evo's are "a high compression cylinder" as the swami stated may be an argument for super-unleaded. I, as I stated, have found 93 octane to be sufficient all though 94 or 95 would be nice insurance if you can find it from a pump.

I am running the 25:1 that tiba suggested and yes, it produces smoke, but I get a good feeling knowing that all that much more oil is in there lubricating. As mentioned, the extra oil does lean the mixture, and what I am wondering from tiba is, if he believes that the extra oil replaces some of the mix that would have been gas, therefore reducing the "cooling effect" of gas on the piston and cylinder?:!

less fuel going inside the engine will make it run hotter but that is simply the nature of the beast, the extra oil also helps in cooling the engine by ensuring there is an oil film between the bore wall & the piston/ring to reduce the friction & wear, more friction = more heat & more wear. this is also true for bearings which are spinning in excess of 13,000rpm when you're at WOT, bearings need oil at those high engine speeds or you'll risk burning a bearing from lack of oil.

when i add more premix to gasoline i also increase your jet size by 1 step richer (+2 to +5) to allow more gasoline in as well. i am very finicky with carb tuning, this is where it all comes down to after you ported the kit & crankcase, installed your fancy pipe & digital ignition. if you can't tune the carb the engine won't make power.
 
less fuel going inside the engine will make it run hotter but that is simply the nature of the beast, the extra oil also helps in cooling the engine by ensuring there is an oil film between the bore wall & the piston/ring to reduce the friction & wear, more friction = more heat & more wear. this is also true for bearings which are spinning in excess of 13,000rpm when you're at WOT, bearings need oil at those high engine speeds or you'll risk burning a bearing from lack of oil.

when i add more premix to gasoline i also increase your jet size by 1 step richer (+2 to +5) to allow more gasoline in as well. i am very finicky with carb tuning, this is where it all comes down to after you ported the kit & crankcase, installed your fancy pipe & digital ignition. if you can't tune the carb the engine won't make power.

i heat my bike up befor i go on it. i make sure my pipe is finger burning hot before riding it. i bought that w3 needle. which made it run better. however its not running perfect is still goes blurrrr at all throtle reange till full throtle were the needle is right open and letting all the fuel into engine. i hear best air fuel ratio is 12:1. who knows how im going to get it 12:1. all i know is that when i add more oil it runns a little worse. i am trying to work out which size needle i need. i dont have a the transmition i wish i could have beause i am struggling financially. i will in time because i am strong minded about things. to me my bike means the world to me and i have come so far to get it even working. that power feeling when it revs right up its increadable. fare enough its a scooter but to some people its like a ferrari. heres whats going around my head:

1.i think needle is too lean w3. w16 dont work i tryed every setting.
2.when i add more fuel to oil it runs a little better.
3.im buggered since i have no racing clutch and i cant get power band in strait away.
4.i am going to buy a jet inbetween 98 and 105 so i can run more oil. at the min i am running 35:1.
5.i already broke one spark plug. the white thing on the end came off and it wont spark.


i am very patient and ready for help.
 
i heat my bike up befor i go on it. i make sure my pipe is finger burning hot before riding it. i bought that w3 needle. which made it run better. however its not running perfect is still goes blurrrr at all throtle reange till full throtle were the needle is right open and letting all the fuel into engine. i hear best air fuel ratio is 12:1. who knows how im going to get it 12:1. all i know is that when i add more oil it runns a little worse. i am trying to work out which size needle i need. i dont have a the transmition i wish i could have beause i am struggling financially. i will in time because i am strong minded about things. to me my bike means the world to me and i have come so far to get it even working. that power feeling when it revs right up its increadable. fare enough its a scooter but to some people its like a ferrari. heres whats going around my head:

1.i think needle is too lean w3. w16 dont work i tryed every setting.
2.when i add more fuel to oil it runs a little better.
3.im buggered since i have no racing clutch and i cant get power band in strait away.
4.i am going to buy a jet inbetween 98 and 105 so i can run more oil. at the min i am running 35:1.
5.i already broke one spark plug. the white thing on the end came off and it wont spark.


i am very patient and ready for help.

i think you should stop riding your scooter until you gather up all the parts you need to complete the modifications, indeed you are running too lean judging from what you described, breaking off the ceramic insulator is a dead giveaway to detonation & an extreme one at that.

also when you said that by mixing in less oil with gas it runs better which is sign of too lean mixtures.
 
...Beta Ark LC scooter with Polini Evo1 LC kit, PHBG21 carb & DPR C30 pipe, i'm currently running a 72 main jet, 50 pilot jet & the needle in the #1 clip position (leanest). this is with the stock airbox on & a 13mm hole drilled by the side of the intake snorkel.


Which needle is in this PHBG 21?
W7, W16 or some other?
 
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w16 But keep in mind on my evo a/c I had a arreche 19mm carb tuned well and it ran fine but when I installed the 21 phbg it didnt want to run In my case at sea level and 60 degrees Farenheit the pilot jet (50 I think)is way too rich I set the needle to the leanest position the mixture screw all the way in and the main jet 92 with no airbox just a malossi red filter(air box makes a big change in jetting).The main is a little lean.I have main and pilot jets on order but for now the bike wont run up to 1/3 throttle after that its crazy!
 
w16 But keep in mind on my evo a/c I had a arreche 19mm carb tuned well and it ran fine but when I installed the 21 phbg it didnt want to run In my case at sea level and 60 degrees Farenheit the pilot jet (50 I think)is way too rich I set the needle to the leanest position the mixture screw all the way in and the main jet 92 with no airbox just a malossi red filter(air box makes a big change in jetting).The main is a little lean.I have main and pilot jets on order but for now the bike wont run up to 1/3 throttle after that its crazy!
On my evo L/C I'm running a 42 idle and it may still be a little rich. Dellorto puts in that 50 so as not to blow up guys bikes. I never messed with the mix screw though yet. Maybe it's good, maybe not, How should I set that? Cause that might be the little bit of "leaning out" that mine still needs.

2.5 turns out; then play with it from there?
 
for a dellorto PHBG21 you run between 1 turn to 2 turns, more than 2 turns & you're too lean with the pilot, any less than 1 turn you're too rich. try 1 turn out bro & see what happens, i ran a 35 pilot jet & it was too lean, i've given it 3.5 turns just for it not to bog down & idle. looking for a 38 to 40 pilot jet.
 
for a dellorto PHBG21 you run between 1 turn to 2 turns, more than 2 turns & you're too lean with the pilot, any less than 1 turn you're too rich. try 1 turn out bro & see what happens, i ran a 35 pilot jet & it was too lean, i've given it 3.5 turns just for it not to bog down & idle. looking for a 38 to 40 pilot jet.
Thanks bud, hey I was reading somewhere that a true sign of being too lean on the idle jet is if the bike runs at high idle for just a bit after closing the throttle, and then settles down. That's exactly what my bike is doing at every stop I make, i.e. it runs at 4000 rpm for a few seconds and then settles down to 2500 which is where I have the idle speed set. Also I still have a bit of a black plug, NGK B11EGV racing plug, so I have signs of lean and also signs of rich, but thanks to your help, I'm getting close to having it dialed in just right. This is why I mentioned the Mix Screw, cuz I haven't changed it from the Dellorto factory setting yet. What you think, bro? Glad to know that you survived the storms down there. Hit me back when you get a chance. Thanks again!
Check out the new pics. 8) I stripped and polished the tranny cover.
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Night shot!
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