Horrible rebuild results!?

Would assure advancer is properly functioning. Might require lubing, or both cleaning and lubing. View movement under timing light while varying rpm by blipping throttle. Advancer might be tending to stick in retarded idle position and sometimes failing to readily advance. This could impair engine performance during acceleration from idle.

Would also double-check valve clearances.

Good Fortune!

Maybe already answered and accomplished but here goes anyways.... Too lazy to review replies and answers...

With throttle cables disconnected, does it still rev on idle?

Does this happen at idle, rev it & stays high as well?

Gas Tank Cap, happen with this open as well?

Does it run better without the pods/air filters installed?

WD-40 for vaccum leaks?

Cycle mag....

Excerpt out of zipped info....

Would be most helpful to have a video of OMR vocalizing the
"Boooooooooowang" sound. :laugh:

Good Fortune!

Here's an excellent article from Marc W. Salvisberg that pretty much depicts everything we've all been informing you of.... Regardless of what carbs you have, the procedures and concepts are the same...

Plum & Larry taught me this exact same thing.... Amazingly worked well, even on my CR Specials....

As you'll review below, don't skimp or cheat for the jetting curves overlap each other so it is important to get each step dialed in first.

1) Main Jet:

2) Needle/clip Position:

3) Now get your pilot/idle circuits dialed in....

Note the difference in Hot or Cold engine temp conditions for which I don't see any reference in your postings... Maybe I missed it...


Dialing In Carbs


Follow steps in order....First, dial in:

1. Top end (full throttle / 5000 rpm to redline) -
Best Main Jet must be selected before starting step 2 (needle height)!

Select Best Main Jet
To get the best, most even top end power (full throttle/after 5000 rpm), select the main jet that produces the highest top speed / pulls hardest at high rpm.

If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large.

Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.

If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small.

In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use!

Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end / cruise later - after step 2.

2. Midrange (full throttle /2500 to 3500 rpm)
Step 1 (Best Main Jet) must be selected before starting step 2!

Select best needle clip position
To get the best power at full throttle / 2500-3500 rpm, adjust the needle height, after you have already selected the best main jet.

If the engine pulls better or is smoother at full throttle/2500-3500 rpm in a full throttle roll-on starting at <1500 rpm when cool but soft and/or rough when at full operating temperature, it is too rich in the midrange and the needle should be lowered.

If the engine pulls better when fully warmed up but still not great between 2500-3500, try raising the needle to richen 2500-3500 rpm.

If the engine pulls equally well between 2500-3500 rpm when cooler as compared to fully warmed up, the needle height is probably properly set.

Do not pay too much attention to the low-end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets (Step 1) that produce the best power at high rpm. You will deal with the low-end / cruise next.

3. Low end (full throttle / 1500 to 2000 rpm)
Step 1 (Best Main Jet) and Step 2 (needle height) must be selected before starting step 3!

Float height (AKA fuel level & how to..)
To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 1500 to 2000 rpm at minimum.

Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.

If the engine has a "wet" rhythmic, soggy area at full throttle / 1500 to 2000, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 1500 to 2000 leaner.

If the engine is "dry" and flat between 1500 to 2000 rpm, raise the fuel level.

Example: change float height from 15mm to 14mm to richen up that area.

REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before final float setting.

Warning: If the engine is left with the fuel level too high,, the engine may foul plugs on the street and will be "soft" and boggy at part throttle operation. Adjust Floats to raise/ lower the Fuel Level.

Base settings are usually given if a particular application has a history of fuel level criticalness. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm.

Reference: a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. Check out and RESET all: Suzuki (all), Yamaha (all) and Kawasaki (if low speed problems occur). Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!

If there are low-end richness problems, even after lowering the fuel level much more than 1.5mm from our initial settings, check for needle wear and needle jet (part of the emulsion tube). See Worn Needle and Worn Needle Jet diagram. It is VERY common for the brass needle jets (in the top of the "emulsion tube") in 36mm, 38mm and 40mm Mikuni CV carbs to wear out in as little as 5,000 miles. Check them for "oblong" wear - the needle jet orifice starts out round! Factory Pro produces stock replacement needle jets / emulsion tubes for 36mm and 38mm Mikuni carbs.

4. Idle and low rpm cruise
Fuel Screw setting (AKA "mixture screws")

There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs have no caps, but use a special "D" shaped driver, usually supplied in the carb recal kit.

Set for smoothest idle and 2nd gear, 2000 rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear, 2000 rpm steady state cruise , and 1/8 throttle high rpm operation.

(pj tuning information)
Pilot fuel mixture screw settings, float level (but, you've "fixed" the fuel level in Step 3 - which you have already done!) AND pilot jet size are the primary sources of mixture delivery during 2000 rpm steady state cruise operation.

If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.

Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.

NOTE: A rich problem gets worse as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.

NOTE: A lean problem gets better as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm!

Successful carb tuning is a combination of science, art, intuition and a lot of wizardry.

Unique engine/exhaust/filter/altitude/temperature combinations may require individualized setups. We are here to help.

We ask that upon completion of installation and tuning, that you call us with specifications of your installation, (pipe brand, filters, advancer, altitude, humidity, temperature and final carb settings) to be entered in our TUNING DATABASE.

Keep at it, discouraging sure but look at what your learning on YOUR KZ.... Keep at it, your close and it will all be good...

I'll do some more searching for CV34 manuals....

OMR

I think you should get another nomination for the "Kayzee humanitarian award" that was a good read....but who cruises at 2000 rpm?

Here's a good article with images for rebuilding/tuning CVK Series...

www.gadgetjq.com/keihin_carb.htm


I PDF'd it for my own CARB library if you need....

kzrider.com/index.php?option=com_docman&...d&gid=474&Itemid=108

OMR

Excerpt out of KZ750 Four Shop manual on Kehin CV34 carbs....

kzrider.com/index.php?option=com_docman&...d&gid=475&Itemid=108

OMR

All excellent information.

For another good source, and available from Z1E:
Click > Sudco Mikuni 4th Edition

Perhaps already suggested, but I like to assure correct float bowl fuel level first before further carb tuning.
Because, as noted, fuel level affects all the carb circuits (choke; primary; mid-range; and main jet).

Also important to assure valve clearances to spec and good ignition with fat blue properly timed spark on new plugs, including functional advancer. All BEFORE addressing carb tuning.

Even perfect carbs can't compensate for a deficient ignition or insufficient compression.

Good Fortune!

Old Man Rock asked:

With throttle cables disconnected, does it still rev on idle?

Don't really understand the question. There's only one cable and it never revs by itself, so it would never rev if I disconnected the cable. If I use the throttle to rev it up past around 1500rpm, it stays up there as the throttle comes back. No kinks in the cable.

Does this happen at idle, rev it & stays high as well?
Yes. That's the main problem. But it does not do this on it's own. Only when I rev it.

Gas Tank Cap, happen with this open as well?
Yep. The vent in the cap is clean.

Does it run better without the pods/air filters installed? During the periods when it's running good, it's about the same.

WD-40 for vaccum leaks? Tried this with carb cleaner but didn't see any smoke.

The spark is nice and fat blue. The sliders are nice and free without being sloppy. The needles are not adjustable.
The compression I haven't yet tested. The problem exists wether the engine is hot or cold. I'm convinced that this is a vacuum leak that I haven't found yet. The jetting may be a bit too big as well, and I will be working on that, but I don't see that causing the revving problem only once in a while.

polkat wrote:

Old Man Rock asked: With throttle cables disconnected, does it still rev on idle?
Don't really understand the question. There's only one cable and it never revs by itself, so it would never rev if I disconnected the cable. If I use the throttle to rev it up past around 1500rpm, it stays up there as the throttle comes back. No kinks in the cable.
Does this happen at idle, rev it & stays high as well?
Yes. That's the main problem. But it does not do this on it's own. Only when I rev it...
WD-40 for vacuum leaks? Tried this with carb cleaner but didn't see any smoke.
The spark is nice and fat blue. The sliders are nice and free without being sloppy. The needles are not adjustable.
The compression I haven't yet tested. The problem exists whether the engine is hot or cold. I'm convinced that this is a vacuum leak that I haven't found yet. The jetting may be a bit too big as well, and I will be working on that, but I don't see that causing the revving problem only once in a while.

With throttle cable(s) disconnected at carb, use bell crank to rev and allow carb spring to pull slides closed against idle thumb screw. This exercise removes cable(s) from the equation to help determine whether cable(s) might be an issue.

Ingestion of WD-40 through an intake leak results in exhaust smoke.

Have valve clearances and advancer function been addressed?

Good Fortune!

Are all carb mounting clamps snug on engine side of carb?

If pilot adjustment screws are supposed to have 0-rings, are the 0-rings there, and in good condition?

[Sorry if already reported.]

Good Fortune!