My carb tuning skills is pretty weak. My 1980 KZ1000 LTD was really having problems with the stock carbs. So I upgraded to mikuni RS flat sides. The motor has been gone through top to bottom and I'm really happy with how it turned out. Because I bored it out a bit I went with the 36 mm carbs at the recommendation of KZzone.com. I put them on and the thing idled perfect. But as soon as I apply a little throttle it sputters and dies. I'm a little lost on where to start. Like I said my carb tuning knowledge is a bit limited. The documentation from mikuni both makes it even more confusing and only slightly helpful.
Is anybody willing to give me a little hand-holding advice?
Personally, I would call APE Racing and speak with them. They sold them to you and will/should provide customer support.. They should have "notes" on what jetting should be for your particular motor set up .
So I got out my handheld AFR meter and welded a bung into the 4:1 collector that is on the bike. At idle it was off the chart lean. Like greater than 25:1. I'm surprised it started. I got on the pilot screw and reset them all to the same place. For reference these are the RS36-D3-K's. So starting to back out he pilot screws, it didn't get down into good range until the screws were 3 full turns out. That seems like a lot especially since the documentation seems to suggest it should only be about 1/2 turn. Do I need to be adjusting the pilot screw and the pilot air jet? Is it this just how it is?
Getting the pilot screws down into a good AFR fixed all the reving problems for sure. But now my upper RPM's are super lean. We'll fix that next.
Changed carbs from factory BS34's to a set of RS36's based on the Mikuni sizing chart. But according to fellow member recommendations, the 36's were "too big" for my engine, so I swapped them out for RS34's when prices were right on ebay.
I'm happy with that decision, but the variety of jetting options have nearly driven me cra...Z!
1982 KZ1100A-2 (sort-of)
1135 since 10/25/19
January 2016 BOTM
Hello what size pistons , cams are you running. ? Ported head. ? I'm having the same problem. I have newly built engine , 1075 12.5:1 . Ported head . Oversize intake & exhaust valves. Open Kerker header. Seems have to choke carbs for about minute before engine will idle , then around 4k rpm , engine pops and seems doesn't want to take the gas . Hard to run it over 4k rpm . Did you have to reset your carbs. My engine builder told me the carbs shouldn't need syncing or jetting.