1981 KZ1000J CARB ISSUES NEED ADVICE

I posted this in my other post "2 RUNNING HOT, 2 NOT" but thought it may get more attention in a new post.
OK fellow riders, I installed the new air box to carb boots, filter and cover. The engine starts occasionally but will only stay running for 30 seconds. I have great spark and when it runs the choke has to be on at least 1/2 way. I have tried adjusting the pilot screws without much success. I can't color tune unless it stays running. I believe I have carb issues but I have rebuilt them 2x, checked the float level per the FSM. Here are my questions.
1) What should the pilot screws be set at for the initial starting point ?
2) Where should I go to have the carbs professionally rebuilt and what should I expect to pay ? (I'm willing to send them to someone on this website who can help, I will pay someone).
3) The little bit it did run I still have #1 and #2 exhaust at a much higher temperature than #3 and #4 with more flow through the #1 and #2 side (left) than the other 2.
Help me out please lol. I live near Myrtle Beach if anyone is close by and has the urge to assist. Thanks in advance

Pilot system is partially or fully blocked.

Baldy110, thanks for your reply. Are you talking about the internal pilot or the external pilot ?

Would find and study the pilot circuit in the particular carbs at hand.

In each CV carb, regardless of exact model, there are probably several paths whereby carb cleaner may be force sprayed through the various sections of the pilot circuit.

Try to block the already clear exits before spraying so that full spray pressure will go through the target unclean area.

And be sure to clean the small orifice(s) into the main carb bore.

Here are some examples to help explain the idea.

And also be sure to wear eye protection when spraying carb cleaner, because the spray always backfires. ALWAYS.








Good Fortune!

Patton, thank you for the extensive drawings. Took the carbs apart today and will blast out tomorrow. I had previously (should have mentioned it before) replaced the #4 carb with one that did not have the "Coasting enricher" and I'm not sure if that makes a difference. The other 3 carbs are numbered with "1356". Before removing the carbs from the engine, I set the external Pilot jets to 1-1/4 turns as you suggested. The engine started and ran without the choke on and sounded really nice and even accelerated when the throttle was twisted but I believe only on #1 and #2 as those pipes got hot (500, #1 and 450 #2) and the other 2 didn't (you could hold your hand on them). Definitely NOT GETTING FUEL as the spark is great. Upon disassembly I found that #1 and #4 main jets were labeled "R210" and #2 and #3 were labeled "R217". I do have 2 more spare carbs that have "R210" jets. I have no idea of the difference but think they should all be the same lol. Attached is the picture of the 2 carbs, 1 with the "Coasting enricher and 1 without. I can't thank everyone enough and please keep the info coming. Thanks, jon

The pilot screws should be set to 2.5 turns for a start. Be sure to remove the screws entirely before soaking in carb dip.

And in case you haven't seen this tutorial before, it may help... zeus.mtsac.edu/~cliff/storage/gs/Mikuni_...Rebuild_Tutorial.pdf

Thank you so much for the information you provided. Carbs are back on for a hopefully successful start tomorrow. What should the exhaust pipe temperatures be where the pipes leave the head ? I can't seem to get an answer to that. Thanks Nessism

I wouldn't fixate on header temps. As I said in your other thread fuel air mixture will dictate that. Concentrate on getting the mixture right on all 4 and the header temps will take care of themselves. You probably cant get an answer on your question because its not a way of tuning and no one has taken note of it.

Edited to add
It just occurred to me when you had the carbs apart did you check the floats didn't leak? ie put them in a bowl of fluid, water, fuel whatever and give them a squeeze like looking for a puncture in a tube? I had great head scratching with a similar issue on a gt380 which had brass type floats. Checked them and they had more holes than a sieve. One cylinder ran extremely hotter than the other two, replaced all 3 floats with new plastic ones and immediately solved the problem.

OH HAPPY DAY LOL, got the bike started after 30 years. I haven't color tuned of vacuum checked yet as I was more concerned about getting it to idle off choke. I did accomplish that and let it run for a good 20 minutes +/-. I was concerned about the exhaust temperature because I was convinced one side was plugged due to more flow on one side than the other. You all were correct with your info about the temps evening out BUT I was also correct when I thought one side was plugged. After it started things began to shoot out of the exhaust on that side. As the engine warmed up sparks began to shoot out for about 15 minutes and the engine started to settle in. It was pretty hilarious actually. The paint is baking rather nicely at this point and we moved to the outside while it did. I want to thank everyone who looked, sent information and chimed in with advice. Like I said, this is a memorial budget build for my pseudo son who's dad passed, this was his dads bike. Thanks again, Jon

Pics of the bike?
Steve

Hey Steve, Attached are 2 pictures. One is the bike with the carbs removed while being rebuilt and the other is a picture of SOME of the plugged exhaust debris coming out of the right side. It was about an inch thick where it piled up in the corner lol. Thanks for your interest. Have a great day, Jon

Looks like baffle material. Can you pull the baffle out? I wonder if there's critter in there.
Steve