By all means try with the cut upp lid as that will lean out the mixture a fair amount enough to see if it improves or gets worse.
On my 93 900ss thé CV carbs are an issue cleaned rebuilt but still nothing good. Smart Carb is my next move. Spoke with Scot P with ItalianIron Classics. italianIron.com. Speak with him. Scot from what everyone says in extremely knowledgeable on carbs.I’m at the wit’s end!
I installed the 944 kit on my 900ss sp. I’m still using the original Mikuni CV carbs. It runs really well once it gets going, but right off idle, below 2000rpm at throttle just cracked open, it bogs and stumbles, sometimes even pops in the airbox. I’m guessing it’s where the transition from the pilot circuit to the needle is, am I right? It idles well, and passed that, it’s all fine, just that area is problematic. I tried different pilot jets, I trieD different fuel screw settings, and I can’t dial it in properly. The carbs are synched perfectly. I’m totally lost as to what to do. Could you please help!
What’s smart carb? I know Mikuni cv carbs are low side on iq score, but I’ve never met a carburetor that was particularly smart either.On my 93 900ss thé CV carbs are an issue cleaned rebuilt but still nothing good. Smart Carb is my next move. Spoke with Scot P with ItalianIron Classics. italianIron.com. Speak with him. Scot from what everyone says in extremely knowledgeable on carbs.
What’s smart carb? I know Mikuni cv carbs aren’t is low side on iq score, but I’ve never met a carburetor that was particularly smart either.
“The SmartCarb is a precision air and fuel metering instrument designed to push the limits of mechanical fuel atomization. Ultra-fine fuel atomization occurs via proprietary venturi features that concentrate and accelerate airflow past a precision ground metering rod.Feb 19, 2021” Lectron carbs are designed by the same man. There are several YouTube videos on them, check out Scots website. His blogs should be far more informative.
i was hot to trot for FCR’s but a friend in Australia who sells the “hand held dyno’s” he mentioned to me that I need to contact Scot in Tucson AZ. A former UK native. I was even looking at flat slides by Mikuni as a backup to the Keihin’s however I’m at 5200’ above sea level, elevation as high as 7200’ & ride at sea level every now & then with levels in between 0-7200’.
something to look at.
Really interesting, in my case the open airbox really leaned the mixture as ducvet mentioned, and 99% removed the stumble (yes it is loud and I love it!!). I will keep following this thread and see what else you come up with. I want to mention one more thing I did, which definitely helped: I moved the clip on the main jets up by one notch (from 5 from the top to 4 from the top). That made the transition from idle to the primary circuit way smoother. Good luck with your troubleshooting!I finally got to ride it properly today. First of all, i really needed it! It was fun! 944 basically still has the same characteristics, just pulls a bit harder and a bit punchier.
Let’s see…ridden and warmed up, it does not pop or bang, so that is good, a huge improvement. It still stumbles as pulling away from dead stop, especially if you roll on slowly, and the transition is still abrupt, BUT it’s a lot more predictable and basically I can ride around it. I still have no idea what’s causing it, but I’m pretty sure that it’s right where the slides start to open, and vibrate as if there isn’t quite enough vacuum to open them. So I’m pinning my hope on the new diaphragm, and maybe swapping the springs with the one from Dynojet (it’s the softest, and longest of the bunch).
I also tried the open airbox. It distinctively improves throttle response, didn’t make ‘stumbling’ any worse, just more noticeable (so it’s worse then), and higher rpm a bit crisper, so I may still be a bit rich in general. I have to say though, it’s so loud! Can’t say I’m a huge fan.
Boy I needed that ride, it felt really good to do that.