carb jetting

Energy One

kennycarr

Member
Ok guys i could really use some help here... ok first off, i am having a problem with backfiring through the carb at cold start and every now and then at crusing speed. Has a dead spot around 55mph..the engine is a stock 107 it has pipes and a k&n spike filter. The carb is a super g. The main jet is 070 and the intermediate jet is 0295 . i live in arkansas so altitude is 55' above sea level at its lowest point and 650 above at its highest point. Any help as to which way i should go with jetting would be greatly appreciated...
 

kennycarr

Member
Not sure of the brand they were on the bike when i bought it. They are a 2" straight like a cobra drag pipe
 

echoniner111

Active Member
Popping is associated with running lean, id try bumping the intermediate jet first . 70 is small for a main jet too, there easy to switch out, theres carb tuning all over this site:2thumbs:


Good luck
 

kennycarr

Member
I knew i would have to richen it up.. was looking for someone that may know a good combination to keep from having to buy a lot of jets...
 

mcgroom

Well-Known Member
I knew i would have to richen it up.. was looking for someone that may know a good combination to keep from having to buy a lot of jets...
Every bike tunes a little different based on mods. Having a master jet kit may not be a bad idea so you can work the carb until you dial it in the way you want it.

I have one that can ship tomorrow if intersted.

Here to help,

Mick
 

Sven

Well-Known Member
... was looking for someone that may know a good combination to keep from having to buy a lot of jets...
Scenario 1:
A.Pops at idle or low rpm is lean at the bottom.
B. Falls on its face about 55mph is it sounds lean from low up to mid point.
C. No getting around a bump from the mid. Might want to follow the low speed suggestion from a previous post.

Scenario 2:

A.I get a pop only when cold? Goes away when warm?
B.That sounds like a cold, condensed, no smooth flame front, because the fuel is more in droplets (condensed). Until the engine warms up, the fuel (expands) back to a mist, the pop is gone; having a cleaner, warmer flame front. We talking that kind of [it goes away] scenario?
C. We still have the 55mph stumble, lag, or driveability is where the 3rd variable comes into play.

Scenario 3:

A. When you unplug intake and exhaust flows, a movement of air has changed. It flows faster. It still enters the engine as the same volume as the stock pipe and filtered air. This is the "SAME AIR" kind of thinker some or say very few think this way.

B. When you port a head, have a hi lift cam, open pipe and velocity stack only, you have the person thinking he has placed, "MORE AIR" into the cylinder chamber. If one thinks that more air happened and not a faster event, it is like saying, the same people that filled a movie house walked in the theater. Someone yells, "FIRE" and they all run out.

C. You have to ask yourself this. If all those molecules entered the slow way, WOThe fudge is moe lass is were you thinking? So you take this speed, add the event that air is lighter than liquid, the air entered faster than the fuel = LEAN.

4th Dimension:

Home he is gas-less are his fingers. Mark-less is his bolt/screw butchering to remove bowl. No, home he opens the tool drawer, no wait, that was the liquid drawer with loc-tie me threads, gas-gear-cinch-and glueBgone. Hee-hee here it tizz. Duct is me tape. Home he is going to slow down the event of air speedee-dee-dee, yes he is he is in deed dee. :roll:


Pee Yes :bang: I've read from the horse is mouth that some need to read my sheet 3 to 15 times before it clicks the engineering INN the cranium. If you have a clogged up air cleaner and it stumbles, causes sooty plugs, etc.; who was the faster move in the cylinder chamber with less restrictions :confused:

Tear A Little Strip ill due ya. :whoop:



Signed,

NOLTT (no one listens to turtle)


:hi:
 

Five Five

Well-Known Member
Every bike tunes a little different based on mods. Having a master jet kit may not be a bad idea so you can work the carb until you dial it in the way you want it.

I have one that can ship tomorrow if intersted.

Here to help,

Mick
How much it the kit ?
 

Raywood

The Pirate
Staff member
Calendar Participant
Troop Supporter
If you would of bought the Mean Mother pipes from BDM it would of came with a 31/76 jets.


Sent from my DROID RAZR using Tapatalk 2
 

francoblay1

The Spaniard
Scenario 1:
bla bla bla bla....
Scenario 2:
bla bla bla...

Scenario 3:

bla bla bla


4th Dimension:

bla bla bla

Pee Yes :bang: bla bla bla :confused:

Tear A Little Strip ill due ya. :whoop:



Signed,

NOLTT (no one listens to turtle)


:hi:
Mate, no offense intended but.... WTF is all that rambling in all your posts??? :confused:


BTW... I think the most popular combo is 76 main / 31 Intermediate. (Also, take the Vent Plug out) File attached. :2thumbs:

:cheers:
 

Attachments

Last edited:

Brew

Troop Supporter
I'm running mean mothers with a spike air cleaner. My combo is a .031 intermediate / .078 main and works very well...
 

bigdogtech01

Well-Known Member
Has the popping just started recently and is just getting worse? Or did you do some modifications to the bike, such as exhaust, and now it's popping on you?

If No mods, and it just started, you might have an intake leak.
Start with checking the rubber plugs on the top of the carb body. They are plugging vacuum nipples on top. If they look at all bad, replace with new ( can be purchased at any auto parts store )

You will also want to check for an intake leak of the manifold seals. With motor warm and able to idle on it's own, spray the intake manifold in the area of the seals from RIGHT side of bike (air cleaner side) Using brake/parts cleaner(one that will not harm paint) spray manifold seal area between intake manifold and head. If any change in idle, you most likely have an intake leak.

You might also want to check the Accelerator pump nozzle inside the carb bore. Take air cleaner off. Using a flashlight, look inside bore of carburetor. Now, twist throttle while still looking inside. If the nozzle does not have a nice fanning spray of fuel, you will need to clean the nozzle. I can tell you how to do that later if your not sure on how to clean it.

Another thing to check, if your using the spike air filter and it just started acting up on you, you might have to remove the small plug on the bottom of the carb using a 5/32" allen wrench. After removing this plug, take the bike for a test ride and see if anything has changed.
 

francoblay1

The Spaniard
Another thing to check, if your using the spike air filter and it just started acting up on you, you might have to remove the small plug on the bottom of the carb using a 5/32" allen wrench. After removing this plug, take the bike for a test ride and see if anything has changed.
That's the Vent Plug I am referring to in my post, right Andrew?

See Point #11 (Part #14) in file attached.

:cheers:
 

Sven

Well-Known Member
Mate, no offense intended but.... WTF is all that rambling in all your posts???
None taken. And here too, no offense, franco, butt you sound like one of them there :job: More Air Think Hers.

I hope your pants are pulled up for dis one. Here is a question for you. I take out plug #14, what will that do? That sig at the bottom of yours, screams bla-bla-bla. So, either you know what that does, or are you saying it's the popular thing to do, so jump off a bridge withe rest of them.

A same air thinker would rattle on about that plug. I just want to hear your version of it. If you are silent about it, well, need I say more [bla]?
 

woodbutcher

Mr. Old Fart member #145
Staff member
None taken. And here too, no offense, franco, butt you sound like one of them there :job: More Air Think Hers.

I hope your pants are pulled up for dis one. Here is a question for you. I take out plug #14, what will that do? That sig at the bottom of yours, screams bla-bla-bla. So, either you know what that does, or are you saying it's the popular thing to do, so jump off a bridge withe rest of them.

A same air thinker would rattle on about that plug. I just want to hear your version of it. If you are silent about it, well, need I say more [bla]?
hey franco, never confront a crazy person. they'll beat you at your own game every time. :roll::roll::roll::roll::roll::roll::roll::roll:
 

Five Five

Well-Known Member
Has the popping just started recently and is just getting worse? Or did you do some modifications to the bike, such as exhaust, and now it's popping on you?

If No mods, and it just started, you might have an intake leak.
Start with checking the rubber plugs on the top of the carb body. They are plugging vacuum nipples on top. If they look at all bad, replace with new ( can be purchased at any auto parts store )

You will also want to check for an intake leak of the manifold seals. With motor warm and able to idle on it's own, spray the intake manifold in the area of the seals from RIGHT side of bike (air cleaner side) Using brake/parts cleaner(one that will not harm paint) spray manifold seal area between intake manifold and head. If any change in idle, you most likely have an intake leak.

You might also want to check the Accelerator pump nozzle inside the carb bore. Take air cleaner off. Using a flashlight, look inside bore of carburetor. Now, twist throttle while still looking inside. If the nozzle does not have a nice fanning spray of fuel, you will need to clean the nozzle. I can tell you how to do that later if your not sure on how to clean it.

Another thing to check, if your using the spike air filter and it just started acting up on you, you might have to remove the small plug on the bottom of the carb using a 5/32" allen wrench. After removing this plug, take the bike for a test ride and see if anything has changed.
Andrew has the correct protocol and advice .... follow his instructions and you should be able to identify the problem and correct it....
 
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