fancy nonstock carburators
- Thread starter Mike Hunt
- Start date
hello fellow riders i recently purchased a 16.16 sha dellroto carbi for my baby with hopes of achiving mach 1 speeds 
but unfortunetly woke up and realized its running to rich and just bogs out ive taken the carb apart with hopes to adj it but no such success as the only thing to do is change the jet(im gonna try the solder and tiny drill bits trick c if that works, doies anyone know the size dril bit i would need for 730 feet above sea level i would appriciate it) wich im not very fond of, also i just orderd a expansion chamber from sbp should i wait till i put that on before i start tuning or just go for it anyways, also does regular solder work for the filling in of the jet and i was wondering if anyone has this carb and wut theyre thought and reviews on it are is it better than those cns carbs or the "racing" ones you se for 60 bucks? any help with my problem is greatly appriciated
but unfortunetly woke up and realized its running to rich and just bogs out ive taken the carb apart with hopes to adj it but no such success as the only thing to do is change the jet(im gonna try the solder and tiny drill bits trick c if that works, doies anyone know the size dril bit i would need for 730 feet above sea level i would appriciate it) wich im not very fond of, also i just orderd a expansion chamber from sbp should i wait till i put that on before i start tuning or just go for it anyways, also does regular solder work for the filling in of the jet and i was wondering if anyone has this carb and wut theyre thought and reviews on it are is it better than those cns carbs or the "racing" ones you se for 60 bucks? any help with my problem is greatly appriciated
From what I can tell ALL aftermarket carbs are a rip off. Without major modifications to the engine it's unlikely anything will perform better than stock. I've had several guys I did bikes for spend big bucks on fancy carbs and not one showed measurable benefit. Most went back to the stock.
Of course those that sell expensive 3rd party carbs and their friends will disagree.
BarelyAWake
New Member
Just a quick thought...
There are two different stock carbs supplied with the "80cc" kits - the older style (but still common) and the newer one with the secondary fuel shut off on it (supplied with the newer Grubee for example). Tho very similar in outward appearance and many of the parts interchangeable, they're jetted drastically differently - the newer one's needle is significantly shorter as an example.
old style;
new style;
(air filter housings may vary)
This different jetting, while still not perfect is a heck of a LOT better than the old style one. While it would be nice to have the fuel/air mix adjustment screw on some of the aftermarket "racing" carbs, getting the jet and needle from the newer carb or just replacing your old one with the new "stock" carb is a step in the right direction at least.
This may also be some of the cause of the varying results people have had switching from stock to aftermarket...
note: while the needle & jet will interchange, the slide itself will not as it's a touch larger.
There are two different stock carbs supplied with the "80cc" kits - the older style (but still common) and the newer one with the secondary fuel shut off on it (supplied with the newer Grubee for example). Tho very similar in outward appearance and many of the parts interchangeable, they're jetted drastically differently - the newer one's needle is significantly shorter as an example.
old style;
new style;
(air filter housings may vary)
This different jetting, while still not perfect is a heck of a LOT better than the old style one. While it would be nice to have the fuel/air mix adjustment screw on some of the aftermarket "racing" carbs, getting the jet and needle from the newer carb or just replacing your old one with the new "stock" carb is a step in the right direction at least.
This may also be some of the cause of the varying results people have had switching from stock to aftermarket...
note: while the needle & jet will interchange, the slide itself will not as it's a touch larger.
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I have not see one of the "new" carbs arrive on a engine yet but did buy one and it didn't perform any better. The only advantage is that shutoff which allows you to remove the bowl w/o losing a filters worth of gas.
The dozens of "old" style I've had are all over the place as far as jet size and performance.
PS Can you see the difference in those needles with the naked eye?
The dozens of "old" style I've had are all over the place as far as jet size and performance.
PS Can you see the difference in those needles with the naked eye?
Bikeguy Joe
Godfather of Motorized Bicycles
Also, when buying an aftermarket carb, you need to be able to tune your engine properly and know how to tune it to see ANY benefit.
You won't see any real performance advantage by just slapping on a "racing carb".
You won't see any real performance advantage by just slapping on a "racing carb".
BarelyAWake
New Member
xlite - yes, there's 1/8th difference (or more) in just needle length, I believe the taper was more acute as the top and point seemed the same size as the old one... but I had no calipers at the time, just put them next to each other and eyeballed - slapped it together and left for work lol
The performance gain could well be environmental, it's getting colder quick up here. *shrug* My bike is really happy w/it tho
The performance gain could well be environmental, it's getting colder quick up here. *shrug* My bike is really happy w/it tho
mountain80
Member
I considered the sha 16 16 myself but have heard mixed results due to the lack of fine tuning that the phbg does have and that is slides needles main jet and pilot jet. The sha does not have a pilot jet just a mixture screw. I have one on its way so i guess we will see what it can do with all the work done to my engine.
let me know how your sha 16.16 goes i just purchased one and i must admit im a sucker for looks this thing is quite sexy for a bicycle but its running so rich that it i cant ride it, wen i first start the bike it runs good for about a minute till the engine warms up then it bogs big time so i slaped my old carb on and waiting for my expansion chamber and my drill bits to come in so that i can get tuning and finally enjoy this carb
Humsuckler
New Member
i "slapped on" a dellorto rep from the pocketbike the other day and recently agreed to recieve a CNS shipped from a member here on the forums..... the dell ****ed my engine, it ran way way too lean.
eedless to say, im not pleased, but i guess ill have a backup motor....
having a mixture screw on the cns will be a great benefit for varying tempretures here in canada
eedless to say, im not pleased, but i guess ill have a backup motor....
having a mixture screw on the cns will be a great benefit for varying tempretures here in canada
Outrunner
New Member
Bikeguy Joe, is absolutely correct. The addition of a larger and adjustable carb
is related to the air flow volume of the engine. If you don't have good
intake and exhaust air flowing through your motor then there won't be a noticeable
increase in performance. You really need to install a better tuned exhaust system
before adding a larger carb for increased performance.
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mountain80
Member
To reiterate what others have said aftermarket carbs have to be tuned to run correctly especially on 2 strokes. ALWAYS start rich and start leaning down from there or else you will burn it down they are NOT prejetted. As a side note my ht carb measured 14.5 mm so a jump to 16 mm is not to radical if the engine is ported and piped. Spit fire i did not order the sha see my previous post i ordered the delllorto 16mm phbg as clamp on style but have to machine a bushing for the carb to clamp on the ht. The huge tunability was worth it to me.
smart man u did your hw before spending the money i wish i would have done the same, oh well i ordered a drill bit set of ebay that starts of at .020" wich i belive is .5mm and the current jet has a number 82 on it im not ruse but im guessing its refering to .82mm i hope anyways never the less i think i should be able to use this drill kit to get the jet were i want it, any suggestikons on wut i can use to hold the bit i dont think a regular chuck can hold such a small bit for one and if there is anything else i can you beside a drill press withouth braking the little drill bit?
mountain80
Member
Yes google pin vise, it is a small handheld chuck which accept small numbered drill bits. I have a set from # 61 to # 80, i soldered and drilled my main jet on the ht motor and i believe it is drilled to 0.026 thou rt now. I did read somewhere that you can solder and redrill certain orifices that pertain to the idle circuit on the sha series but i can't remember where maybe google it. When i do get my carb tuned maybe ill sell off the extra jets well have to see how it goes.
Bikeguy Joe
Godfather of Motorized Bicycles
A .026" or .027" bit will get you in the ballpark.
Thankx for all the help guys i ordered a set of drill bits and a pin vice now im just doin the waiting game before it all gets here, quick question about the pin vice thought, is it hard to use as u spin it with your fingers and i asume that these drill bits are very delicate and very easy to brake correct i dont have any experience using any drill bit smaller than 1/64
As you noted breaking is the biggest issue. Stay away from cobalt and carbide. Strange but true the cheapest ones are best. And always buy spare bits.
BarelyAWake
New Member
xlite's got the right idea - those hard bit types are for drillin' the tough stuff, as you will just be going through solder (and mebbe brass if you miss) you'll be fine with the regular steel bits, they're far less brittle.
Outrunner
New Member
A Dremel tool works perfectly too. I use a rechargeable one that I bought at Wal-Marts. You need to buy a little chuck for it also.You will be surprised how
often it will be used.