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Theory on a rough idle/bogging problem.

Posted: Fri Jul 27, 2012 12:51 am
by JBenjimin
Does this sound reasonable or am I out in left field?

I've had my Stella 2T since the beginning of April, I had 1200 miles on it Saturday when I ran out of fuel for the first time and had to switch to reserve. I made it to the gas station (I was only 3 miles when I ran out) I refueled and switched off of reserve. I continued my ride home 6 or 7 miles. I didn't ride Sunday, then on Monday took it for a ride to Buffalo about 15 miles or so, all was fine until I was on some really rough road, then it started to idle really rough and when I would start from a stop it would want to die (I stalled it 3 times that way) then it would be fine for a bit and then idle rough again, the third or forth time it was idling rough lasted for a long time. Then it cleared up on the way home and has been fine since.

On Tuesday I took out the jets and cleaned them, checked the plug, and put everything back together. It was fine yesterday on a nice 45 minute ride.

My theory is that since I had never used reserve before there was some gunk that I pulled into the fuel line and or carb, and once I hit the bumpy road I dislodged it, and it clogged the idle jet. On the ride home if finally passed through the jet which is why I didn't see any clogs and it has been fine since.

Does my theory make sense or should I be concerned that I haven't yet found the cause of the problem?

Posted: Fri Jul 27, 2012 12:54 am
by gitsum79
Your theory sounds right to me :wink:

Posted: Fri Jul 27, 2012 2:28 am
by talindsay
Wow, that kind of rational analysis doesn't typically happen in a scooter forum, I'm impressed. Yes, that sounds about right. I like to run my bikes onto reserve fairly regularly to avoid the bottom of the tank getting too sludgy, and I've never had trouble with it, but of course correlation doesn't imply causality so it might just be that I haven't gotten sludgy gas.

Posted: Fri Jul 27, 2012 2:00 pm
by psssniper
So what about an inline fuel filter? Seems like it would be a good idea or is the fuel flow on these Stellas too sensitive for a filter?

Posted: Fri Jul 27, 2012 3:40 pm
by JohnKiniston
psssniper wrote:So what about an inline fuel filter? Seems like it would be a good idea or is the fuel flow on these Stellas too sensitive for a filter?
Stella's have a fuel filter. Well at least the 2-T bikes do, I've not taken apart the carburetor on my 4T yet to see if it's got one but I think it's got an inline.

In the carb the upper most assembly that looks kinda like a pot lid for lack of better words, it's got a single screw through it. Unscrew it and pull off the lid and you'll see the filter.

Posted: Fri Jul 27, 2012 5:45 pm
by Gobigblue
Right below letter "E"

Posted: Fri Jul 27, 2012 5:47 pm
by JohnKiniston
Gobigblue wrote:Right below letter "E"
Thanks! Yep that's what I was trying to describe exactly.

On my bike I'm running without a filter for a higher flow-rate.

Posted: Fri Jul 27, 2012 11:16 pm
by psssniper
Ah thanks for that info on the filter. I have an '09 2T that I just picked up here in southern calif and it had 262 miles on it. Orig owner had a shop put a Sito+, a P200 air filter and also rejetted When I got it, after it had sat forever, it ran terrible, had to choke it forever and keep the choke partially on just to get it to run at all, also had to stay on the throttle as it would bog and die at "idle". Used some seafoam and then after that didn't help too much I blew out the jets, voila. Runs like a champ, set the idle and she's happy now. Still running a little seafoam in each tank. Ill take a look at that filter just for fun.

Posted: Mon Jul 30, 2012 6:14 pm
by jmer1234
talindsay wrote:Wow, that kind of rational analysis doesn't typically happen in a scooter forum, I'm impressed. Yes, that sounds about right. I like to run my bikes onto reserve fairly regularly to avoid the bottom of the tank getting too sludgy, and I've never had trouble with it, but of course correlation doesn't imply causality so it might just be that I haven't gotten sludgy gas.
I have heard the postulation of not wanting to get into the bottom of a tank because of particulates that may have settled out. I can understand that possibility in a stationary field tank that you may use to refuel a farm truck or tractor, but scooter gas tanks are in constant motion. The contents are continually stirred, keeping everything in solution. When would you form a sludge that does not immediately dissolve in the solvent gasoline the minute you start moving?

My theory is that the OP just got some particulates or a little water in the tank of gas that was purchased.

Posted: Tue Jul 31, 2012 8:10 am
by BuddyRaton
JohnKiniston wrote:
Gobigblue wrote:Right below letter "E"
Thanks! Yep that's what I was trying to describe exactly.

On my bike I'm running without a filter for a higher flow-rate.
I've done that too. You just have to accept that you may get some junk in your jets. That being said I only pull the filter when running a high flow fuel tap.

Posted: Tue Jul 31, 2012 8:23 am
by BuddyRaton
jmer1234 wrote:When would you form a sludge that does not immediately dissolve in the solvent gasoline the minute you start moving?
When the cap or top of the tank starts to rust and flakes off for example. You wouldn't believe the kind of stuff I've seen in tanks. Rust, washers, screws, leaves, etc etc. When you need to go to reserve all the junk is in a pretty small volume of fuel and tends to settle at the low point...the tap intake.

I remember one guy that posted a photo of his sight glass with a stick in it. He had no idea how it got there!