will not idle need some sugestions

I have a kz750 with a set of Mikuni BS34(they were on the bike when I bought her used) on it. I cleaned the carbs and replaced the jets with new ones (same size and type) that I bought at Z1-enterprise during the downtime of winter. I also had the diaphrams re-done at the place in England. I put the carbs back on and started the old girl up but she will not idle very well. It is not smooth and has a hard time stay running. She runs like a rocket when get her above 2000 rpms. Nice and smooth. But anything below that she is rough almost like a bad spark plug rough. Sometimes the carbs will when idling stay high on the idle 3000 to 3500 rpms.
I have checked my valve clearances and though are good. I changed out my fuel filter, I checked my float levels and they are good (slow to fill the tub to check the levels), I checked voltage at the coils and I have 11.82 volts. I changed the spark plugs just in case. I even sprayed wd 40 around my boots and the idle did not change.
I am not sure what else to check for Please help???
thanks,
Max

Will lob a wild guess. Perhaps ignition advancer unit (if so equipped) is sticking in advanced position and failing to return to retarded idle position at low rpm (where F mark is supposed to align).

On models fitted with the springs/counterweight style automatic advancer unit, cleaning and lubing may return the unit to proper function.

Good Luck!

The mechanical advancer will be under a CD sized cover on the right side of the crankshaft(as you sit on the bike).

Remove the 12 or 13 MM bolt and the advancer should come off the end of the crank after the pick up coil screws are removed.

Clean the advancer and check for binding in the weights that control retard and advance, and lube it with light oil at the places that move. Re-assemble the advancer on the crank and see if the idle is better.

i would make sure the pilot jets and circuit are clean first.

When you sprayed WD-40 around the "boots" do you mean the carb holders where they attach to the cylinder head or the air cleaner side? A small air leak where the carb holders mate up to the cylinder head will cause very rough idle. Ed

sounds like pilot circuits or the pilot jets been thru it many times in the past i have done upwards of a hundred sets of carbs over the course of the spring and early summer it sounds like they need a good cleaning and i don't mean apperance the pilot circuits have to have carb cleaner shot into them and then blown out in a few seconds with compressed air. remember to remove your brand new slides as the carb cleaner will affect your rubber diaphrams.

Follow the link for the Gunson (or similar) Color Tune for Pilot adjustments.... Half way through the clip, listen closely for you can hear the change in idle when adjusting only one carb pilot....

NOTE: This clip was recorded on the first carb only, still had three others to do and guess how she purr's now...

kzrider.com/index.php?option=com_kunena&...ew&catid=3&id=266611

Now I'm no carb Guru nor do I claim to be but I will say this from what I have learned in studying/researching/accomplishing my setup and these are brand spanking new carbs mind you....

In the manuals, they say rotate your pilots out let's say 1.5 turns for a given carb setup.... This is a starting point only.... And I don't give a rats ass who says otherwise, every motor, bike, setup will be slightly different for what worked on my motor will not be 100% effective on yours... And this is with exactly the same motor and carb configuration on any two different bikes...

Well, we do that, does it start, yup, does it run, yup does it run OPTIMALLY... HELL NO it doesn't! There's just no friggin way it ever will be, too many variables effect this especially on a 30 year old motor/carb setup...

Each carb final pilot adjustment will end up slightly different, end of story! Other variables such as air filters, vacuum, compression, valve conditions, timing, exhaust, air leaks etc... all come into effect...

Even in my case, started out at 1.5 turns where I thought wow, cool, should be good to go... Well I was wrong!

Plugs still looked carbonized (firing rich). Hard start, slight miss in the idle, rough idle, hit throttle sounded pretty good but slightly missing just the same etc.... More research was required into learning my carbs and tuning...

Then I was turned onto the Color Tune by a guy (from another KZ site) for who as a living is motorcycle carb tuner/mechanic....

I found in using the color tune where all carbs where slightly different in the final pilot adjustments! Example, carbs 1 & 2 are around 1 5/8 turns out while 3 & 4 are more close two 2 turns out.... :ohmy: :huh:

In speaking with several other members (many years experience in KZ motor rebuilding) here and elsewhere that I queried thinking something was wrong...

All replied the same, this is NORMAL for even new carbs will not be 100% the same due to all the variables associated....

Then throw into the mix a proper carb synch, difference between the analog gauges and a Morgan column gauge for example.... Sorry Jeff....

The Analog gauges will work and get you really close, no doubt... They have been used for 30 years so if your not looking for dead nuts on for OPTIMUM performance, then good to go with these gauges...

Now with ideal and desired Pilot and carb synch accomplished for optimum performance. Even on a cold start (AZ cold mind you) I don't even need choke, one push of the start button and this old girl fires to life and purr's a like a kitten... In riding her where the jetting isn't even completed yet, you'd better be holding on for she accelerates with no lull or hesitations, just pure in your face mean ass adrenalin G-force... Not joking, she actually pulls you off the handle bars, it's whacked!

Actually got my heart pumping on the first twist of the throttle... Almost pissed myself.... :laugh:

Ok, so I've bored you guys enough....

OMR


























:laugh:

Regarding the Colortune product; I see that the offer different kits for different plug diameters (10mm, 12mm, 14mm) but I didn't see how they deal with other differences in spark plugs. For example, the depth that the plug seats isn't the same for every engine, so if the plug they provide is shorter or longer than the one your engine uses wouldn't that effect the way the engine runs because the spark would be higher or lower in the combustion chamber and even the compression ratio may be affected by the difference in plug length? Also, if the heat range of the plug is different that the recommended range, would that have an impact? I don't know much (anything) about the effects of different spark plugs on the idling of an engine, but it seems strange to me that the engine performance wouldn't change if one plug type was used to fine tune an engine and then a different plug type was installed to operate the engine. Maybe the differences are so minor that it doesn't matter. I guess the good news is that it works well. Ed

They offer adaptors for different depth plugs.... The 14mm I have is the same as the NGK B8ES plugs...

Vist their site or I believ it was Mark1122 who found a differnt source, cheaper version of them without the mirrored extension...

Same time, as some of the variables you mentioned for which I'm sure would come into effect, how much unknown to me but if your running rich, lean and just going by ear for pilot adjustments, how much are you gaining...

Sorry but I don't have that type of experience to do so by ear to that level of performance verus being able to see the ignition chamber flame....

As the saying goes, a picture is worth a thousand words...

OMR

the color tune system work quite well and about the only other thing on the market that will do as agood a job or better would be a 5000.00 dollar e.g.a so i think if your really concerned about how your bike is running at low speed this is your best option and the price is definitly right.

I think I found the problem. I went a head and pulled the carbs off and torn them down. I found some stuff on two of the screens for the needle/seat. Knowing I had new fuel line and new fuel filter I was a little puzzled. Well it turned out the new fuel filter did not have its element inside the unit. I went ahead and cleaned the carbs with carb cleaner and put everything back together. It will be monday or tuesday before I can test because I am taking the filter back to the kawaski shop to exchange. Thanks for everyone's help. I hope that was the problem. I will post my results.

thanks,

Max