This is what i had on my bike before new mods:
*Stock exhaust drilled to 1/2 on 1st baffle
*120 MAIN JET
**OEM air filter
*Lid on air box with no snorkle
*Kauba screw


This is what i did according to https://www.kawasakiforums.com/forum...ad.php?t=2041:
*Changed to 124 main jet
*Added high performance snorkle
*Drilled vent slide
*Drilled bottom right hole of airbox

Now my bike loses power when i pin down the gas. 1-2k it accelerates and at 3k it boggs down then regains power slowly. HUH?
--I played around with the fuel adjustment screw from 1-6 turns and its still the same.

-Tried removing air filter, air box lid, and it still does the same thing.

What did i do wrong? How do i fix it? Is it too lean?
Also it takes longer to start.

 

sounds like it's lean, but I can't help you I never changed jets

 

When I did my carb, I did not get the rubber in for the slide right and the bike ran like crap.

That is where I would start.

Where did you get the info about drilling the air box and slide?

David

 

You have to change the needle in the carb. Get the N1TC or DynoJet.

Ride on
Brewster

 

When the slide vacuum hole on a CV carburetor is made larger than it should be ( "drilled the slide") the carb starts to operate more and more like a direct lift carb. A direct lift without accelerator pump, mind you.

If you've ever looked into the throat a CV carb while engine is running you can see the that the slide moves pretty darn fast. Not INSTAT closed -> open but quite fast. Fast enough that it tracks the rising revs just fine.

Now with a too big vacuum port at the bottom of the slide, the slide slams open as soon as you pin the throttle open. And then happens what the CV carb was invented to prevent from happening.
The air velocity dies in the venturi (revs rise much slower than the venturi cross section) and mixture goes way lean.
In a direct lift carbs the AP is used to prevent this by squirting extra fuel into the intake.

Then as the revs slowly rise, the air velocity gradually recovers and A/F gets back to the right ballpark.

The bad news is that only way to fix this is to go back to correct size vacuum port. Hopefully you have an extra un-drilled slide somewhere stashed away.
You can make steady-state too rich by using a needle with steeper tapper to help this problem a little.
But it is not the real answer and comes with the expense of running too rich when cruising at steady throttle.

If you have the patience you could do this fun little eye opener. Take the slide out, epoxy the vacuum port completely closed and then re-drill a original size hole there. Leave all your other new mods in place and see what happens. It runs like a champ again.

--
Mikko

 

FlyingFinn is dead on. That is the "glory" of a cv carb. No accelerator pump needed. It gives the engine just what fuel it needs. Air and fuel travel at different speeds and have different inertia. The CV carb makes up for that by using demand and flow of air. So it can compensate for large throttle opening at a low rpm and the engine not cough or sneeze with out a good squirt of gas.

 

I did the same thing, I have a Thread somewhere on this forum about it..I'll search for it and post the link..

 

Here you go - https://www.kawasakiforums.com/forum...ad.php?t=24360

Hope it helps!