Midrange sputter/bog

I’ve been trying to resurrect my old Ruckus, found a good deal on a '16 stock GET. Put a generic PZ16 on it. After swapping the stock 35/75 jets for 38/78, it starts and idles fine, and runs great at full throttle. The only issue I’m having is that, sometimes, at about 1/4 throttle, it sputters and loses power. If I give it more or less throttle, it smooths right out. I’m thinking a needle-clip adjustment might fix this, but I’m not sure if it is more likely caused by being too rich or too lean.

This is kind of embarrassing, at one time I would have known, but old age takes a definite toll on memory (I’m 67 now).

Can ya help a brother out?

I have this exact problem. It might be old gas maybe. It doesn’t exactly bog but it kinda like skips or stutters at mid throttle. If it’s the same exact problem as me then I don’t think it’s a rich or lean condition because it’s never done that before. My scooter was sitting for about 3 years. You may also need to clean the carb too if it’s been sitting too. Make sure the jets are not clogged or anything like that.

I’ve put some seafoam in the tank ( didn’t do anything). rode my scooter until i needed to fill up with gas. I put premium in. It has less of the problem now but perhaps the old gas may need to be completely flushed out . I will report back after my next fill up

Thanks for the reply! It could have been old gas. I drained it and put in fresh gas with a shot of Techron. Haven’t had a chance to ride since then.

I live about a mile down a really rough dirt/gravel road where I have to hold it at 10-15 mph, and that’s when it happens. Once I hit pavement, it accelerates right through that spot and runs really good at full throttle. So it’s not really a problem, more of an annoyance. Still, I’d like to get it figured out.

I’ll have a better idea this week. I’ll be rriding the scooter regularly this week.
But yeah mine has the problem mid throttle only too. If i hold it around 20mph at anywhere close to mid throttle it would do that. However, if I didn’t hold the throttle and just rolled the throttle to wide open it has no problems getting through the speed.

Here is an idea since you mentioned you added an additive. I believe my problem started when I added the seafoam in the gas tank. I’ve ridden it until the light came on and put in fresh gas without any additives and the problem is less noticable now. So maybe it was the additive. Next gas up probably know for sure though. Keep you posted !

Hey Goggles, just wanted to let you know I got my problem solved. Don’t know if it will help you any, I’m running an aftermarket slide-type carb, which has an adjustable needle for the main jet. It has 5 grooves in the top of the needle, with a clip. You move the clip to different grooves to adjust rich/lean at midrange. I first richened it one groove, and that made it worse. So, I leaned it out two grooves past the original position, and now it’s running perfect!

Is your scoot stock, with the factory airbox and exhaust? Have you re-jetted it or anything?

I also have the slide carb installed. I believe it is the shengwey one I bought many years ago from jcracing. I never touched the needle setting before, but I have rejetted the bike according to my conditions when I got the carb which was probably 10 years. It’s been running with no issues until this year. However it’s been sitting for 2-3 years. So that’s why I figured it can’t be a lean rich condition can it? I’m still living int he same area and no changes has not been made in that time.

I only really got a chance to get out once this week since it’s been raining all week. I can say the issue is way less now since i gassed upwith no additives. I also tried to hold that mid throttle problem area to see if it stil was making those sounds. it only does briefly, but before i could hold it and it would stay like that in that range. Perhaps it is just the old gas that’s still in the system and the additive.

I think we may have a little different problem. Mine doesn’t exactly bog or sputter. It’s like a little blip sound. Best i can describe it is that it would sound like it bounced off the rev limit.

Thanks for the suggestion though! I actually tried messing around with the needle clip like 2 weeks ago trying to remedy the problem, but didn’t do anything. I lost that securing clip that secures the needle (not the adjusting needle thank goodness!). I stuck a paper clip in there though:D

I think you’re probably right, it shouldn’t go rich/lean just from sitting, moat likely a combination of old gas and maybe a little too much seafoam.

I was surprised by how much difference moving the needle clip one slot made on mine.