[black]

recently put a jet kit on my bike, ivan's, and having some problems with it, flat spot in first gear from 4-6k...

Well i've heard suggestion to shim the needles, reset the float levels and add a washer/clip...

ok i can do al that stuff, but why??
As in when i do this stuff, how does it affect the bike exactly?

I want to get to the WHY and HOW
I guess the theory behind jetting a bike, the reall nitty gritty theoretical stuff of how air passes ove teh needles etc.. i know somebasic stuff but not enough..

anybody have a tech article i could read that explains jetting and exactly what is going on in there?

or any body have a desire to explainto me over IM or email???
lost here and i really want to learn here

 

[Chetnik]

http://www.motocross.com/motoprof/pdffiles/carb101.pdf

Happy reading

 

[black]

oh wow....uhh thanks.. i'll read it tommorrow, but quick ?

throttle slide vlaves, do all bikes have this? and do jet kits replace these at all??i dont'
remember this when installing it?

also... on my carbs i have "velocity stacks" are these justt the beginning of the "venturis"? because they taper into the carbs just like fig 1.?

and why in my bike are the 2 inner carbs have "taller" velocity stacks than the outer carbs?

hmmm....
thanks for the info though!!!

 

[black]

ohh any info on the theory of float levels?

 

[Lee]

What year is your bike?

 

[black]

2000....

 

[RowdyRed94]

So, you want someone to spend as much time typing as you would reading?

:redflip

 

[sonicrete]

Best advice about float level. Leave them the fvck alone. You are trying to get them EVEN more than anything and usually the factory is very close. If the floats leak fuel it is because there is debris,ie dirt,trapped between the needle and seat. Bending the pee out of the tab on the float will probably do more damage than good.

Carb adjustment in a nut shell.

Idle jet,idle screw is only for idle,up to say 1/8 throttle.

Needle and needle jet (the hole size the needle fits in) is for controlling the fuel added as the slide raises. Moving the "clip" position adjusts the amount of fuel at various position. Different needles with a different "taper" can adjust fuel available at different ends of the travel. Hopefully the jet kit manufacturer has already made a good choice on the needle taper and you only need to adjust the height,ie clip position.

Main jet is for only wide open,ie 3/4 to full throttle.

The problem is with CV type carbs the throttle position is not exactly where the slide is raised to. The motor must "suck" the slides open and this is the problem using "pod" type filters or open stacks.

On a CV type carb if it is really lean,the bike will go no faster from say 1/2 throttle up. Basically the motor runs out of fuel and turning the throttle further cannot lift the slides more.due to lack of fuel. The opposite is true if over rich,the bike will accelerate nice then miss and fall on its face. Basically the slides open clear up and "flood" the motor.

 

[cesj]

Float Height is very important. I found this out the hard way. What I ended up doing is calling Jet Kit manufacturer and asking them what settings they recommend for your area. When I did mine I did everything no problem except for floats. I eventually paid a freind of mine with his own shop to teach me how to measure properly. :thumb Thanks again Andy(Metric Cycles). Bike now runs very good but now I am in the process of ajusting valves.

 

[atombomb]

this is what we call the learning curve for home mechanics...

 

[D duck]

http://www.factorypro.com/tech/carbtun.html

 

[da1]

There in lies madness

 

[P-Dog 187]

Don't mess with the float level Pleeessse! if it was right before you installed the kit should still be ok

Go backwards through the installation procedure of the jet kit. Uninstalling one part at a time. When it starts to run right you know where your problem lies and where you need to make adjustment (IE. Needle e-clip or spacers, main jet, etc.) If the kit was specifically designed for your bike you shouldn't have to make to much of and adjustment to make it work right. Contact manufactuer with your problem. They may know right away what you did wrong.
This means carbs are going to have to come off and on numerous times

It's a learning process good luck

 

[black]

wellthe thing is... ivans jet kjit for my bike states a float level of 5mm
the kawi spec for the flaot levels ar 7 +/- 2 mm.... oh wel it lookslike i wil set he float levels then go thrut he process of choosign the best main jet.

wont' be able to work on it for a few weks as i am busy.. soon hough sooon

 

[cesj]

Don't know about Ivan's but FactoryPro has good instructions as far as choosing the right order to install things. Should work with the Ivan's parts just follow the instructions for FactoryPro. I don't remember exactly but I think they state to select the main jets first, then the needles, then float height. Or something like that. :confused

www.factorypro.com

 

[[HEL]DeAlessio]

cool ive been looking for a jet kit for my vtr250 and factory pro actualy has them.

 

[RuffRider]

Don't mess with the float level Pleeessse! if it was right before you installed the kit should still be ok

Go backwards through the installation procedure of the jet kit. Uninstalling one part at a time. When it starts to run right you know where your problem lies and where you need to make adjustment (IE. Needle e-clip or spacers, main jet, etc.) If the kit was specifically designed for your bike you shouldn't have to make to much of and adjustment to make it work right. Contact manufactuer with your problem. They may know right away what you did wrong.
This means carbs are going to have to come off and on numerous times

It's a learning process good luck

i also have a dead spot at 7000rpm on my bike and i got the right one for mine. but at the same time that little spert doesnt bother me when i seen what a stage 3 does. it woke it the fuck up

 

[sonicrete]

Go back up to my earlier post. Almost all motorcycle carburetors operate the same way. The CV type carbs you are not in direct control of the slide,it moves by engine vacuum,but the operating ranges are the same. If you have a "bog" in the midrange it is more than likely the height of the needle. On jet kits the needle will have several "clip" positions to adjust the height of the needle,realtive to the slide. The needle determines the amount of fuel by the taper restricting the flow of the open hole size. Lowering the clip position will raise the needle and make the mixture richer.

Screwing with the float height is dangerous. If too low there is insufficient fuel in the bowl and if too high,can over flow into the motor or out the vents. Think a toilet tank that runs all night and you can see the problem. Changing the float height is to make the fuel "pull" into the motor easier,because it has less distance to lift. The problem can occur during hard braking with elevated fuel levels can cause the motor to flood from the fuel rushing forward. If the floats are not "even" is more problem than the actual level as this will make one cylinder run different than another. The shut off needle has a spring preload and a good way to check for non-equal float level is to turn the carb rack upside down and look down the row of floats. If they all look nearly the same I would leave them alone until at least I rode the bike after installing the jet kit.