Please I am sure someone has had this issue before, I saw a thread about it a while ago but for the life of me I cannot relocate it! I promise it's a good read because I always try to keep it funny so more ppl respond THANK YOU - Here we go...

So this had happened once before after I ran out of gas (just got the thing and didn't realize how much it sucks it up LOL) where after refilling it would "SPUTTER" while accelerating and sometimes even while holding the throttle steady under a middle gear and not under serious load. I've seen this before on other bikes, and I figured the float bowls were empty and they just needed to refill (my logic was if you are hauling *** it doesn't give them enough time to top off... Me thinks?)

I was ready to take the tank off and go at it with the carbs and ultrasonic cleaner but after a day or two of sitting it just fixed itself! (I think overnight the CARB FAIRY maybe stopped by and sprinkled some "magic dust" on it... not the Cheech and Chong kind though LOL). I mean like PERFECT it was accelerating and pulling like a damn freight train through all 6 gears and I even touched just over 150 MPH once and thought I saw GOD (and almost pissed myself Haha). Was running GREAT for several weeks then I got bogged down with another project, started to paint some of the panels so I had it apart, so it sat for maybe 2-3 weeks but it had 3/4 tank of FRESH GAS in it. I'm in Florida and it's super humid now and I know all about small engines and the EVIL "hygroscopic" (Google it) ALCOHOL and what it can do in these climates. Now I do see a TINY bit of rust scale inside the tank which I plan to CLR shake & bake to remove. I will also try and keep it topped off with gas from now on (all gas tanks take a "deep breath" once a day as the temperature & humidity change, keeping them near 100% full of gas can negate this THX DAD

SO NOW MY ISSUE -> After finally running her after an almost 3 week nap she is SPUTTERING again like crazy but this is where it's weird, I don't think it's a fuel delivery issue because the FIRST THREE GEARS she has INCREDIBLE acceleration (like perfect even under serious load) and only starts sputtering in 4th, 5th and 6th gear. Once it starts sputtering though... It's like she gives up and almost every gear she continues to sputter, even with the throttle at the middle or low position (well maybe not 1st gear but the sputtering is crazy). Has anybody ever seen this before?? I'm pretty handy with tools and have a little side hustle fixing & repairing scooters and other small CC engines (for fun & profit).

I was reading somewhere that you have to adjust the vacuum on all four carburetors so they are the same, and I'm a little bit concerned about taking all the carbs off this beast since I don't want to mess anything up. I would rather have the CARB FAIRY stop by again and fix it for me (dammit I forgot to put a couple dollars under the tires for her last time - maybe that's why?)

I am completely stumped and would love to know why this is happening again! Maybe I can back-flush the carbs and fuel filter with carb cleaner and my air compressor set at low PSI to avoid taking the carbs out and tearing a gasket. I've done this before with scooter carbs after using carb cleaner and it usually works like a charm.

ANY HELP OR INSIGHT TO THIS ISSUE WILL BE GREATLY APPRECIATED

Many thanks!!

 

Hey there,

It does sound like you've got some gunk in there somewhere. The fact that you noted the throttle position is a big help. I've attached a pic of how the different circuits work inside the carb for reference.

About your question about the vacuum, you do not remove the carbs when syncing them. The bike actually has to be running to perform this maintenance action correctly.

 

I'd start with the basics - drain the gas from the tank and make sure it's good - you might just have a bad fill up.