Idling Rich 82 KZ550C LTD

The bike has been stripped down to bare metal and built back up. Carburetors cleaned and rebuilt. Airbox removed and replaced with pods. Slip-on cocktail shaker mufflers with 8" can opener baffles wrapped with fiberglass. Jet kit installed 100 main jets on 1 and 4, 102.5 main jets on 2 and 3.

The bike was running very rich when first ran after the rebuild. After a few test runs I could smell unburnt gas on the exhaust. Spark plugs 1/2 oil fouled and 3/4 carbon fouled. Oil also contaminated with gas. Replaced all spark plugs and changed oil/oil filter. Raised needle to stock postion. Adjusted floats as the we're to high with the rebuild kit needle and seat.

Yesterday started bike to more black smoke. Ran for a while to warm up and black smoke never cleared up but the unburnt gas smell is gone. Another odd thing is that the air mixture screws had very little effect on the idle. To the point I had them all closed and the bike never died. Also after opening up throttle and snapping shut big cloud of black smoke.

Ok so here is my question do you think it just needs a good run to blow out the cob webs ,"carbon build up", or are there some other steps that I should be taking first. Thought about running a Seafoam 50/50 clean out on the engine.

RB

The air screw on your bike actually richens the low speed fuel mixture when it is screwed in clockwise, if you have the stock TK-22 carburetors. Try running it at 1-1/4 turns out to start with. My stock 550 is set at 1-1/8.

For initial test run I started at 1-1/2 turns out. Bike idles fine, no real issue with the idle. But shouldn't bike stall with air mixture screw seated even with pods.

Here are a couple pictures of the progress.

aarb77 wrote: For initial test run I started at 1-1/2 turns out. Bike idles fine, no real issue with the idle. But shouldn't bike stall with air mixture screw seated even with pods.

No, the engine will not die out with the air screw fully seated. The idle and low speed fuel/air mixture is pre-mixed before the air screw. The air screw just fine tunes the final mixture adjustment. On other carburetors with an idle mixture screw, the engine should stall with that screw fully seated, since the air and fuel mixture is shut off from the engine at idle.

Thanks GPz550D1. Was hoping I didn't miss something while cleaning the carbs. Got any ideas on the black smoke? Or should I say steps I should take to resolve this issue.

aarb77 wrote: Thanks GPz550D1. Was hoping I didn't miss something while cleaning the carbs. Got any ideas on the black smoke? Or should I say steps I should take to resolve this issue.

Would say that you are still running too rich. Perhaps the float level is still too high. Maybe a faulty float (filled with gas) or one of the float valve assemblies is not quite right or sticking? Also, if a carburetor vent is plugged up, the carburetor would not run correctly. I am sure you have read how to check float level using the clear tube method?

If the bike is tuned properly, fully seating the air screws will stall the bike. On mine, just fully seating one screw will make it very rough and almost die. Seating a second will kill the idle. When the mixture screws have little to no effect, something else is wrong... like idling on the main circuit, or a bad vac leak, or a sync that is far off.

On the most recent rejet project, on a standard KZ550 (TK22's), running pods and Mac 4-into-1, we ended up using the stock jets, and simply shimmed the needle precisely. We used 0.63mm shims with .028" guitar string spacers. This allowed us to use the stock 92 mains, and the stock 32 pilots, and stock needles.

Have you read my site about the imitation factory needles? They end up way too rich at all clip positions, and are not really usable. My site has details on how to identify them. We initially had them and it was baffling how adjusting the needle to the leanest setting still made everything way too rich. It wasn't until I measured them that is made sense.

home.comcast.net/~loudgpz/GPZweb/TK22mai...K22threeNeedles.html

home.comcast.net/~loudgpz/GPZweb/TK22mai...TK22rebuildKits.html

Looks like you hit the nail on the head. When I purchased this bike the guy gave me these rebuild kits. When I went to rejet the carbs I used the needle, float needle/seat, and gaskets from this kit. Fuel level is good and needle is dropped all the way.
I still have the stock needles and stock jets. I also have the stock size jets from the rebuild kit. Do you have any info on the jets will they be ok to use?

Use the stock Kawasaki jets. Aftermarket parts are not precise. I bought some what I thought were Mikuni main jets and the bike wouldn't run for SHT. I pulled them out and put them side by side with REAL Mikuni jets and the new ones were drilled differently. Just a small thing like that made all the difference. The Yamaha dealer was shocked and gave me a refund.
Steve

loudhvx wrote: If the bike is tuned properly, fully seating the air screws will stall the bike. On mine, just fully seating one screw will make it very rough and almost die. Seating a second will kill the idle. When the mixture screws have little to no effect, something else is wrong... like idling on the main circuit, or a bad vac leak, or a sync that is far off.

My understanding is that the air screw is a fine-tuning adjustment allowing the carburetor to be slightly adjusted for variances in atmospheric conditions. It does not stall out the engine on mine when pilot screws are fully seated and I used Lou's carburetor information page to help set my TK-22's up. The engine runs great and averages 60 miles per gallon.

Put the stock Kawasaki needles back in and overly rich exhaust is gone! Have it shimmed with a nylon spacer and needle shim. Thanks loudhvx!! Also took a look at the off brand pilot jets that were not installed and you can see how bad there drilling is off.