Too rich

My friend and I have been having trouble getting a set of 29 smoothies to work. They are fantastic in appearance but after several - many many cleanings - there seems to be an endless supply of sand blasting medium in them. We have them on my Kz1000 described in my sig. Bike runs but is rich. figuring obviously too much fuel / not enough air. The bike will run without the air jets in it. We can back them all the way out and it's the same. 117.5 mains are in it. We are scratching our heads trying to think of what we are missing. Sometimes it's the obvious. Any ideas ?

How are the valve adjustments?
Steve

I am the :evil: working on the 29's... all valve clearances are at >005... Just like I like them. Going to check choke system next see if there isn't something there causing the rich ness... Maybe order some 15 pilots ???I :evil: :evil: :evil: :evil:

DaytonaKZ wrote: I am the :evil: working on the 29's... all valve clearances are at >005... Just like I like them. Going to check choke system next see if there isn't something there causing the rich ness... Maybe order some 15 pilots ???I :evil: :evil: :evil: :evil:

...I wish I was too RICH!

What size pilots are in there now?
Steve

Current pilots are 17's I'm pretty sure.

Stock motor? The 29 and 33's are hard to tune. If they are used and came off a suzuki or Honda, The slides will be 2.0. The Kaws call for 1.5's. 2.0 is lean so a larger pilot is needed. Add that to the main system being set up with smaller air jets because the vacuum signal is stronger, you will have a rich condition through the midrange on up. I'm dealing with that now.
jetsrus.com/carburetor/carb_mikuni_VM29_...oded_view_parts.html
I would suggest if you can afford it, go with what is called for in the application chart on that page. Even then remember these are "race carbs" and may not behave like the stock ones that came with the bike.
Steve

good information steve. So if we lower the needle down to 1 from where its at now 2 then we will be getting a leaner mixture? but might need a larger jet system to make up for that loss? We are ordering some smaller jets but will play around with lowering the needles down a level.

Motor has 1015 weisco pistions and Z1 cams. Otherwise stock yes.

these are 1.5 slides ...

Correction: these ARE 2.5 slides...

2,5 way lean. Think about it this way, If the mixture is too lean on the bottom, you have to step over the flat spot and into the main circuit sooner where it will become way rich. 1,5's would get you where you need to be. 2.5's are meant for an accelerator pump in the system.
My 33's call for much smaller pilots with 1.5 cutaways. I have 2.0 so I'm running 70's and 130 mains. It runs good but it could be better with the right slides and jets.
Steve

KzRyan wrote: . . . 29 smoothies . . . Kz1000 . . . Bike runs but is rich. . . The bike will run without the air jets in it. We can back them all the way out and it's the same. 117.5 mains are in it. . . .

When turning the pilot air screw has no effect at low idle rpm, it may indicate an imperfect pilot circuit. Would suspect that the pilot circuits are not yet perfectly clean, being at least partially responsible for the overly rich running.

Over-rich running at any throttle position less than wide open probably does not involve main jet size.

Over-rich running at idle rpm when turning the pilot air screw has no effect is imo not due to jet needle configuration, or clip position, or slide type, or main jet size, and probably not due to the under-size #17.5 pilot jet (which according to the Mikuni chart should be a #25).

Would use the middle needle-clip position.

If not already done, would perform clear-tube testing to assure that fuel levels are not too high, because too high fuel levels can result in over-rich mixture at all throttle positions even with otherwise perfect carbs.

Might possibly involve an imperfect enrichener circuit, such as failure for whatever reason of the plungers to fully descend and close off the choke -- a relatively rare condition.



If not already done, the carbs should also be very accurately bench-synced.

Good Fortune!