KZ650 float settings and tuning problems

The Milkman wrote:

Double check for vacuum leaks at the manifolds, and any vacuum hoses by spraying them with carb cleaner.

Liberally sprayed everywhere I can think of. No air leaks detected.

The Milkman wrote:

Also, do you still have the emission hoses still hooked up to the valve cover the way they were from the factory, if that system isn't working right it will cause popping.

Since the bike has pods, there is no airbox to run the "exhaust" hose back to, so it simply terminates under the seat, with a pod filter on it.

How do you determine whether it's working properly or not?

wiredgeorge wrote:

Slide actuators are bolted to the common throttle rod. Unfortunately, when you change the slide height with one carb in a mechanical slide system, the other three slides are affected since they are all linked by the rod. Synchronizing 100s of set of carbs has taught me this lesson. I would suggest purchase of the correct tool; a manometer with four gauges.

I understand the need for proper synchronization, but, I don't see how carbs being slightly out of synch could cause popping. Can you recommend an inexpensive synch tool?

wiredgeorge wrote:

There are many reasons for popping... ignition timing, valve clearance issues, poor compression, air leaks at the exhaust gasket location and ANY intake location, etc.

I'm confident timing and valve clearances are correct. Compression was discussed earlier in this thread, and, while not optimal, is not all that bad. I've sprayed carb cleaner all over the carbs, vacuum fittings, etc., and can find no air leaks. How would I check for exhaust gasket leaks, aside from taking the header off?

jccwall, take the smog valve off and run a hose tube to tube, also plug where the vacuum lines went to the carb holders. WG meantioned awhile back that these "smog" systems actually create more backfiring thru the exhaust system as they induce more oxygen to promote "better" combustion. Mine stopped working 20 years ago. You can save the system and put it in a corner somewhere.

Post edited by: Bluemeanie, at: 2007/11/22 09:29

I had taken the backfiring issue as decelleration popping. The backfiring you describe is either an air leak or weak spark if the valves have been adjusted.

Incomplete combustion or a lean condition from air leaking. Could also be ignition timing but you said that was OK.

wiredgeorge wrote:

I had taken the backfiring issue as decelleration popping. The backfiring you describe is either an air leak or weak spark if the valves have been adjusted.

Incomplete combustion or a lean condition from air leaking. Could also be ignition timing but you said that was OK.

Just put new Dyna Green coils on, with Dyna wires, and a Dyna S ignition. Timing was set exactly as per instructions that came with the Dyna S ignition, and I've gone back and rechecked it.

I've sprayed brake cleaner everywhere on the carbs and vacuum fittings I can think of, and can spot no air leak.

What do you think of what Bluemeanie wrote about the smog valve? Could that be causing it? It makes sense to me, but, I have zero experience here.

For what it's worth, my neighbor's brother lives out of state, and meticulously restores old motorcycles for a hobby. He's in town for Thanksgiving, and heard me warming the bike up a few minutes ago. He walked over and immediately said the bike is lean. I told him what I've been through with it, and he said he didn't have any experience with old Kaws, and had to get back to his family, but, just heariung it idle, he said he knew for sure it was lean.

Post edited by: jccwall, at: 2007/11/22 15:43

Bluemeanie wrote:

jccwall, take the smog valve off and run a hose tube to tube, also plug where the vacuum lines went to the carb holders. WG meantioned awhile back that these "smog" systems actually create more backfiring thru the exhaust system as they induce more oxygen to promote "better" combustion. Mine stopped working 20 years ago. You can save the system and put it in a corner somewhere.<br><br>Post edited by: Bluemeanie, at: 2007/11/22 09:29

The valve appears to be working properly. Wouldn't simply plugging the vacuum lines going to the carb holders be good enough to test if that's where the popping is coming from?

Post edited by: jccwall, at: 2007/11/24 19:28

Hola?

ok, used some clear tubing, put some oil in it to try a cheap way of doing the vaccum sync. didnt work the way i had hoped. read it somewhere on the net. had also read somewhere about using ball bearings. 1 in each carb. anyone know where i can get the correct size bearings to do this?

if all else fails will just break down and buy the guage set.

jim

Like everyone says, a lot of things could cause your popping. But go ahead and unhook the vacuum line to the smog valve and cap off at the carbs. Take her for a ride and let us know...

Bluemeanie wrote:

Like everyone says, a lot of things could cause your popping. But go ahead and unhook the vacuum line to the smog valve and cap off at the carbs. Take her for a ride and let us know...

Tried that, no change.

Got the correct baffle from Mac and installed it. Customer hates it, says it sounds like a salad shooter. He keeps squawking about "Loud Pipes Save Lives", etc. Personally, I prefer it this way, quiet, and no droning at 80mph.

The baffle improved on the popping, but, it is still there. It also still backfires through the pipe when you back off the throttle.

It pops at idle, and it pops at steady cruise at 2000, 3000, 3500, and 4000 rpm. The popping is intermittent, not steady. Any time you rev it to over 2500 rpm and let off the throttle, it backfires.

I'm at a loss.

Sorry if overlooked, but have the valve clearances been checked? Too tight might cause popping.

Also, thinking one of the carb diagrams earlier posted showed both types pilot mixture adjustment, one being the side located air mixture style and the other being the bottom located fuel mixture style. Side located air mixture turns in to enrichen, whereas bottom located fuel mixture turns out to enrichen. If not already done, would try enrichening pilot circuit (say one turn) to see if this helps eliminate popping (if caused by too lean pilot circuit mixture).

Just quick thoughts, and realizing you're probably already way ahead of them.

Good luck.

I've checked and rechecked the valve settings, they're set to the specs in the Clymer manual. Also, i would think the popping would be steady if it was valve settings. it's intermittent.

These carbs have air bleeds, and I'm sure they are set properly. I've been over them half a dozen times, adjusting them as per wiredgeorge's instructions.

I ordered a manometer today:

cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll...m=&item=330196846109

I'll vacuum-synch the carbs as soon as i get it to eliminate that possibility, but, I just don't think that's the problem.