the big spring that sits against the lid ( coper colored ) on the top of a stock pred carb, what is its perpose in life? i adjusted the clip and it runs like a scolded ape without the spring. but with it it runs 10x slower than the bike being stock. i have not move the clip back to the reg position becouse it runs so good the way i have it now! thanks once again for any and all input!

 

That spring controls the way the plunger opens. Without it I would think the plunger would pop to the top and run rich....

 

but what if the spring is out all together. it realy rips with it out. will it hurt anything? and the gold washer dose it go on the top or bottom of the clip? when i took them off i forgot what was on top of what. to many broooskies! thanks!

 

bump!

 

Let me explain.....The spring goes into the 'slide', out the bottom of the slide is the needle. The needle goes through your 'main' jet. When you are at idle, there is very little vacuum from the engine, so the needle is most of the way through, bottomed out in the main jet, allowing very little gas flow. When you increase the throttle, which increases the vacuum, the slide lifts and pulls the 'tapered' needle out of the main jet, allowing more fuel flow. When you have it wide open throttle, the vacuum is highest causes the slide to lift, lifting the needle out of the main jet and allowing full fuel flow according to the size of your main jet.

The spring, put pressure on the slide to push the needle back down in the main jet and also allows for rapid throttle response. Without the spring, you lose throttle response and cannot properly control your low to midrange response/rpm's.

Without the spring it is also possible to tear the diaphragm on the slide, the rubber part on top of the slide/carb, which will cause the slide to stay down all the time and you could only idle. Its not a good idea to remove your spring.

If you notice the your machine runs faster top end with the spring removed, then you have the needle in the wrong position, not allowing enough fuel at full throttle or you have the wrong size main jet installed...or there is possibly a better main jet to get you more top end. You will then have to adjust the needle for the new main jet to maintain proper response in low and midrange.

dave

 

Speeeedy;

Cut four coils off the spring and put it back in. Also notice at the bottom of the slide where the needle slides into. Their you will find two extra holes in front towards the front of the carb. Drill out those holes with a 1/8 drill bit. It should rip just like it did before.

The washer goes under the large plastic washer. In other words it is the first thing that touches the slide when you install the needle back in.

 

The spring is the counter balance to the vacumn on the slide. Its ported, so at idle, theres no vacumn going to it.
Think of it, like the old holley vacumn operated 4 barrel carbs. The secondarys are controlled by vacumn, as the engine needs more fuel the vacumn will rise, this pulls the secondarys open more. Same with the slide...as the motor hits higher vacumn, the slide opens ,more to allow more flow.
With out the spring, it possible to bog the motor, by opening too quick and letting more gas in, than the motor can handle. This was a problem with street 4 barrel carbs, if they had mechanical secondaries.
This article can explain it better.
cv carb

 

thanks for the replys. that helped! i have it figured out now!